# Models for grinding HSS Lathe Tools



## mikey

In a recent thread by @Darkbluesky, http://www.hobby-machinist.com/thre...tools-ideas-of-what-to-buy.62043/#post-511618, @ttabbal joked about sending me blanks to be ground into lathe tools ... he was joking! But it got me to thinking ... yeah, I know it's not a good thing when Mikey gets to thinking ... but it got me thinking that reading about how a tool is ground and having a decent tool in your hands that you can see and touch are two different things. 

So, what if I ground a set of tools from 3/8" mild steel keystock (just to discourage some bozo from actually trying to cut something with the models) so people could hold it in their hands to look at. You could use them to plop onto your tool rest to see what the rest angles should be and maybe how your hands have to align to grind the tool. You could also buy some keystock and duplicate them for a permanent reference, and then pass them on to the next guy who wants to have a look.

I'm thinking of making *THREE* sets of these model tools and mailing them out to guys who are interested. We would need to figure out a list if there are more than three guys interested in seeing them, and YOU GUYS need to sort out how to keep track of these things. I would guess one to two weeks of holding time per person would be reasonable and the guy who has them would pay to flat rate ship it to the next guy on the list. Naturally, the only guys who can get on the list would be members of the HM forum.

As to which tools to include in the set, I'll leave that to you guys. We can discuss it here and see if we can come to some consensus. I will probably write a set of notes with details on how each tool is ground and why the angles are what they are and how you can modify them to better suit your needs; these notes would be posted to this thread.

I don't know if this is of interest to anyone but on the off chance that it is, let's talk about this and see if we can make it real. I'll spring for the keystock, grind the models and send them out. After that, you guys need to sort out how to get them distributed. The last guy on the list can hang onto them until some other HM member contacts them or you can send it back to me so I can do the same.

Let me be very clear about one more thing. The models will be of tools as *I* grind them for use in *my* shop on my lathe(s). It is one way, not necessarily the right way or the only way. My hope is that it will help you to find your own way of grinding tools that work for you.

Thoughts?

Mikey


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## Aukai




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## tweinke

I think that would be an awesome idea. Possibly grind a standard LH, RH, threading tool, and ??? I for one would be very interested in actually being able to touch a tool that has the potential to work instead of guessing from pictures.


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## mikey

tweinke said:


> I think that would be an awesome idea. Possibly grind a standard LH, RH, threading tool, and ??? I for one would be very interested in actually being able to touch a tool that has the potential to work instead of guessing from pictures.



Okay, thanks, Todd. Are you thinking a general purpose RH tool, a roughing tool or ... ? I was thinking maybe a RH general purpose tool, a RH knife (facing) tool and a threading tool. A LH version is just a mirror image that you can sort out easily. I'm okay with whatever you guys feel the need for.


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## tweinke

I like your thinking, much better then my newbie thoughts. only reason I mentioned a LH tool was for some it may be hard to grasp the mirror image thing. I really have enjoyed your posts on tool grinding and can grind a tool that will cut but to be able to touch a proper tool and see it in my own hands would just be cool. I am in the process of getting ready to build a belt grinder with tool sharpening as the primary reason. I hope more guys chime in on this soon!


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## Ulma Doctor

great idea Mikey. 
if you see and know what a good example of a hand sharpened tool is, it is much easier to reproduce one


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## mikey

tweinke said:


> I like your thinking, much better then my newbie thoughts. only reason I mentioned a LH tool was for some it may be hard to grasp the mirror image thing. I really have enjoyed your posts on tool grinding and can grind a tool that will cut but to be able to touch a proper tool and see it in my own hands would just be cool. I am in the process of getting ready to build a belt grinder with tool sharpening as the primary reason. I hope more guys chime in on this soon!



Thanks, Todd. Yeah, I think it might be helpful to actually hold a tool in your hand that, if reproduced in HSS, will actually work the way it is intended to work. All of us, to some extent, are visual learners and if we do this then I hope it works out okay.

As for the mirror image thing, I'll write it up so that you can't possibly misunderstand how it is done. I'm listening, Todd and will do what I can to make this work for you.


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## Ken from ontario

Mike, the idea is great , I would love to own a RH  facing/turning bit that you have ground but I'll be honest with you, for a newbie like myself , this bit will be something to look at and compare other bits with periodically   as a reference piece, it is not something I could let go after a short while. if you remember I bought a "training set" from LMS but it is a basic set and I still would like to have a single bit made by you for my own personal use. 
I know it may sound selfish but that's how I feel about it.


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## Groundhog

I think that is a great idea. I've been grinding my tools for some time but have fallen into bad habits resulting in non-standard tools (my own special misshapen grinds). They seem to work, but I'm not sure why.
It would be nice to compare those to a properly ground tool.


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## mikey

Ulma Doctor said:


> great idea Mikey.
> if you see and know what a good example of a hand sharpened tool is, it is much easier to reproduce one



Thanks, Mike! For you experienced guys, this may not be of interest but I remember all too well what my tools looked like when I started - they were pretty bad!!! 

I actually had a set of pre-ground tools from Sherline and it helped but what I didn't know was that those tools were ground to the typical geometry found in a tool angle table and I couldn't take a decent cut with them on my Sherline lathe. A 0.020" deep cut in 12L14 steel resulted in chatter and it took a long time, experimentation and frustration to figure out how a tool cuts. Now I can triple that 0.020" deep cut in 12L14 mild steel with my Square Tool and have no chatter on a Sherline lathe; the only thing that changed is the geometry of the tool. I will say that those original Sherline tools allowed me to hone my profanity skills, though!


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## mikey

Ken from ontario said:


> Mike, the idea is great , I would love to own a RH  facing/turning bit that you have ground but I'll be honest with you, for a newbie like myself , this bit will be something to look at and compare other bits with periodically   as a reference piece, it is not something I could let go after a short while. if you remember I bought a "training set" from LMS but it is a basic set and I still would like to have a single bit made by you for my own personal use.
> I know it may sound selfish but that's how I feel about it.



Ken, thanks for being honest. Let's you and I discuss this in a PM - contact me when you have time. I'm partly responsible for egging you on about being lathe-less so I feel some responsibility ...


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## mikey

Groundhog said:


> I think that is a great idea. I've been grinding my tools for some time but have fallen into bad habits resulting in non-standard tools (my own special misshapen grinds). They seem to work, but I'm not sure why.
> It would be nice to compare those to a properly ground tool.



Thanks for your input, Groundhog. I plan to grind modified tools that work for me. They will not be standard tools that you can grind from the data found in any tool grinding table. The models I have in mind should work better than a standard geometry tool but whether they are "proper", I don't know.


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## thomas s

Mikey, Thank for taking the time to do this. I think it is a great idea count me in. Thomas S.


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## DHarris

Brilliant idea Mikey!!!  and your write-up of the tools / grinds will be invaluable to close the loop for all of us newbies!!

Well done Sir!

Dave Harris


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## ttabbal

I think this is a great idea! Thanks for offering to do something like this. I may have to order some blanks even without yet having a lathe just to have some grinding time with a reference in hand. 

I may have to start a thread about grinder upgrades. My HF grinder is kinda crappy.. But with some work on the rest it might be usable to start with.


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## mikey

Okay, there seems to be some interest. Now we need to decide which tools to include in the set. I agree with Todd that a RH turning tool and threading tool would be a good idea but I'm not married to the idea. What do you guys think?

I think a knife tool would be a good addition but since you can face with a turning tool, it might not be what you want. Just know that a knife tool will face better than a turning tool and is excellent for thin work sizing cuts. It will take a whisper-thin cut on a small diameter work piece and it also works pretty good for chamfering. Since facing is a basic lathe operation it is a good tool to know how to grind but its up to you guys. Let me know.


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## Groundhog

mikey said:


> Thanks for your input, Groundhog. I plan to grind modified tools that work for me. They will not be standard tools that you can grind from the data found in any tool grinding table. The models I have in mind should work better than a standard geometry tool but whether they are "proper", I don't know.


Actually I was being sarcastic. I have been grinding my tools improperly (although they seem to work most times!) and would like properly ground tools to compare my poorly ground tools with. I need to break my bad habits.


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## mikey

Groundhog said:


> Actually I was being sarcastic. I have been grinding my tools improperly (although they seem to work most times!) and would like properly ground tools to compare my poorly ground tools with. I need to break my bad habits.



Mike, I hope my models meet your expectations. If they help you in any way then I'll be happy but don't expect too much - they're just turning tools.

I keep saying this but nobody can possibly make an uglier tool with more facets than I did as a beginner. I thought I tossed those early tools but I may have some of my early efforts somewhere in this shop; if I can find them I will show them so you know I'm not kidding.


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## ttabbal

Obviously, I'm coming at this with little practical knowledge... I would like to have an example of at least the most common tools. Turning, threading, and facing being the most obvious. The knife tool sounds useful.

One thing that comes to mind is surface finish. It sounds like a tool with a larger radius gives a better finish. Rough and finish versions of one of the tools might be useful. 

Perhaps number them with matching examples from written info or times in the video? So we can read/watch while looking at the tool? I don't want to make a lot of work for you, so feel free to do whatever. Just thinking out loud as a beginner.


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## Rockytime

mikey said:


> Thanks, Mike! For you experienced guys, this may not be of interest but I remember all too well what my tools looked like when I started - they were pretty bad!!!
> 
> <SNIP> Now I can triple that 0.020" deep cut in 12L14 mild steel with my Square Tool and have no chatter on a Sherline lathe; <SNIP>
> 
> I've used my Sherline for 20 years and can't even imagine a .060 depth even in brass. How do you do that?


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## mikey

Rockytime, just my general purpose square tool will take a 0.050" deep roughing cut in 12L14 on my Sherline lathe as shown below:




My tool for mild steel has a bit more side rake and will take 0.060" in a single pass without chattering.

EDIT: I should answer your question as to how I do that. I increase the relief and side rake angles but keep the back rake angle near baseline. This reduces cutting forces significantly while also focusing those cutting forces at the forward area of the side cutting edge. A Sherline lathe is pretty light and cannot handle the cutting forces a standard geometry tool produces but give it a little help with the geometry and it becomes capable of much more. The same is true for all lathes, not just a little Sherline.


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## mikey

ttabbal said:


> Obviously, I'm coming at this with little practical knowledge... I would like to have an example of at least the most common tools. Turning, threading, and facing being the most obvious. The knife tool sounds useful.
> 
> One thing that comes to mind is surface finish. It sounds like a tool with a larger radius gives a better finish. Rough and finish versions of one of the tools might be useful.
> 
> Perhaps number them with matching examples from written info or times in the video? So we can read/watch while looking at the tool? I don't want to make a lot of work for you, so feel free to do whatever. Just thinking out loud as a beginner.



Okay, a turning tool, facing tool and threading tool. This covers most general lathe operations. Anything else?

By the way, finishes are affected by the nose radius, relief angles and back rake. We'll make that clearer as we go along.

I never made a video, although I've thought about it.


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## Z2V

Mikey, 
Very generous of you to offer to do this. I'm very interested in seeing your tools so count me in. Do you use a jig or do you grind free hand? Do you use a bench grinder or belt? I have an 8" bench grinder and I'm also in the process of building a belt grinder.
Great idea, thank you


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## mikey

Z2V said:


> Mikey,
> Very generous of you to offer to do this. I'm very interested in seeing your tools so count me in. Do you use a jig or do you grind free hand? Do you use a bench grinder or belt? I have an 8" bench grinder and I'm also in the process of building a belt grinder.
> Great idea, thank you



I use a belt sander but I cheat - I have a really good tool rest. The tool is otherwise ground "free hand" without a jig of any kind. You can do the same thing on a bench grinder provided you can get the tool rest at the right angles. That's why I thought models might help folks see the rest angles a bit better.


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## Aukai

I always thought I was born too late, looks like I have good timing for this opportunity. This is an awesome offer, I will donate blanks. I would like to take part, I have a new grinder, and some new AL wheels I'd like to break in, not wear out on the first try. LOL


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## mikey

Aukai said:


> I always thought I was born too late, looks like I have good timing for this opportunity. This is an awesome offer, I will donate blanks. I would like to take part, I have a new grinder, and some new AL wheels I'd like to break in, not wear out on the first try. LOL



No need to donate anything. I already have the 3/8" keyway stock so it's no problem. I will order some new belts for my sander and get them done once we figure out which tools the guys want to see.


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## Z2V

I would be particularly interested in the knife for facing and a threading tool in addition to general turning. Could you possibly show the difference between a roughing and finishing tool also. 
Would also like to see your tool rest if you would care to share a pic or two. I'm looking for ideas for my own belt grinder.
Again, thank you


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## mikey

Z2V said:


> I would be particularly interested in the knife for facing and a threading tool in addition to general turning. Could you possibly show the difference between a roughing and finishing tool also.
> Would also like to see your tool rest if you would care to share a pic or two. I'm looking for ideas for my own belt grinder.
> Again, thank you



You can see my grinder and tool rest here: http://www.machinistblog.com/modifying-a-craftsman-2-x-42-inch-belt-sander-for-tool-grinding/#more-5349. 

You should also look at the thread by @Alan H on his tool rest: http://www.hobby-machinist.com/thre...and-work-table-upgrades-lots-of-photos.61968/

@ddickey also has a 2x72 grinder he is setting up for tool grinding; you can PM him.

As for roughing and finishing tools, if you intend to use separate tools for all three common lathe operations (roughing, finishing and facing) then we can do that. Having separate tools was popular before we had quick change tool posts and all three types were used with the tool shanks perpendicular to the work. The advent of the quick change post changed that and now most guys prefer to use a general purpose tool to rough and finish. 

The relief and rake angles are different on a general purpose tool vs the older style tools and you have to understand how they differ because general purpose tools are a compromise. In order for a single tool to handle heavy cutting loads and then turn around and take fine sizing cuts with a fine finish is a tall order. And yet, we can come pretty close if we add a little more side and end relief, add in a bit more back rake and increase our nose radius just a little bit. These changes are subtle but make a huge difference in how the tool performs. 

You also have to bear in mind that no tool cuts all materials equally well. A general purpose tool is really a shape, not a designated tool with specific angles. You can use the same shape but have relief and rake angles that are optimized for a given material class and that tool will work better for that material class. 

Rather than grind a tool for every material class, I'll grind a Square Tool. This is a general purpose tool that will work pretty well with most materials commonly used in a hobby shop. If you work with a particular kind of material a lot then it will be better to change the angles on the tool to better suit that material. For example, a general purpose tool for aluminum will have larger relief angles, more side rake and way more back rake than a Square Tool will have but the overall shape of the tool will be the same. The aluminum tool will typically have a slightly larger nose radius than one for say, steel; this gives us a mirror finish that a smaller nose radius would not do as well. 

As you can see, there is a lot to grinding a good tool. The thing is, once you see how the table angle is set to grind a relief angle on my model then it is a simple step to know that increasing that angle a degree or two more will reduce cutting forces further and allow the tool to cut with greater ease. Similarly, once you have a solid idea of how the side rake is ground then that really opens the door to changing how your tool can cut with lower cutting forces and cutting temperatures. I can tell you how to do it but if you also see the model so you can set the actual table angle then that makes it simpler to understand. I think that's been the missing link for a lot of guys and is the key reason for doing this model tool thing.

What I intend is to write an article that goes with the model tools. I will show how each is ground and why each angle is chosen. I will also tell you when to change the angles, how to change them and why. Once you are clear on this stuff it is a simple step to deciding how to grind a tool that will do exactly what you want it to do. 

I don't know how much you know about tool geometry or tool grinding, Jeff, so pardon me if I'm insulting you by referring you to an article that I wrote that might make all of this clearer. You can see it here:
http://www.machinistblog.com/?s=belt+sander&submit=Search. Its in three parts but all the articles are on that page. Look it over and we can go further if you need to.


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## .LMS.

Mikey - Please count me in, and thank you for doing this!


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## dlane

a shear tool , acme thread,


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## Glenn Brooks

Mikey,  you might consider making your models with wood blanks. You can even make,them 2x or 3x larger than standard tooling.  Our instructor in trade school used large wooden tools for instructional,purposes, and they were very helpful to,see and handle.  Regular size works also, and no one can mistake wood for HSS.

Glenn


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## Rockytime

mikey said:


> Rockytime, just my general purpose square tool will take a 0.050" deep roughing cut in 12L14 on my Sherline lathe as shown below:
> 
> View attachment 241311
> 
> 
> My tool for mild steel has a bit more side rake and will take 0.060" in a single pass without chattering.
> 
> EDIT: I should answer your question as to how I do that. I increase the relief and side rake angles but keep the back rake angle near baseline. This reduces cutting forces significantly while also focusing those cutting forces at the forward area of the side cutting edge. A Sherline lathe is pretty light and cannot handle the cutting forces a standard geometry tool produces but give it a little help with the geometry and it becomes capable of much more. The same is true for all lathes, not just a little Sherline.



Thanks Mikey,
Appreciate the reply and the photo. I am strictly a visual learner. If you can give the angles I can grind it. After over 20 years as a hobby machinist I never did grind proper angles. Since my work is mostly for clock repair and small engine building my tools worked ok. Most used is brass and aluminum but I have a large stash of 12L14. My neighbor had a shop and whenever he ordered steel he would a couple of 12' lengths for me. Over a period of time I ended up with an assortment from 1/4" to 1". Since selling my BP and 12" lathe I only use up to 1/2". Though my projects now are small it would be nice to occasionally take deeper cuts. Very impressed with your belt sander conversion.
Regards, Less


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## mikey

dlane said:


> a shear tool , acme thread,



Morning Derrick. I actually have never ground a shear tool, although I probably will one day just to see how it works. I have read it works well on 1018 and if it does then it would be worth grinding one because nothing else I know of will finish 1018 nicely. 

An Acme thread tool might be something we should discuss at a later time. It isn't something we use every day and I wanted to grind tools that the majority of us might find useful on a daily basis. So far, most of the guys seem to like the idea of tools for the basic lathe operations - facing, turning and threading. What do you think?


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## mikey

Glenn Brooks said:


> Mikey,  you might consider making your models with wood blanks. You can even make,them 2x or 3x larger than standard tooling.  Our instructor in trade school used large wooden tools for instructional,purposes, and they were very helpful to,see and handle.  Regular size works also, and no one can mistake wood for HSS.
> 
> Glenn



Thanks, Glenn. Yeah, wood would be sooo much easier to grind and I actually considered it. But then I thought is would be better to have a tool that you can set on the tool rest and actually move your hands around to see how you would need to hold the bit to get the right angle to cut a particular face. That is what I think is hard for guys to visualize. My hope is that if I tell them how I ground that particular feature and they can match what I'm saying in real time, with the tool on the rest, then it might just click.

I also wanted to show them tools that I know, without a doubt, will cut as intended. If I were giving a class on this subject, for sure a wooden model would be far more useful.

Thanks for the suggestion, Glenn!


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## dlane

Yup just the basic turning tools for everyday turning should be helpful for many people.


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## mikey

Rockytime said:


> Thanks Mikey,
> Appreciate the reply and the photo. I am strictly a visual learner. If you can give the angles I can grind it. After over 20 years as a hobby machinist I never did grind proper angles. Since my work is mostly for clock repair and small engine building my tools worked ok. Most used is brass and aluminum but I have a large stash of 12L14. My neighbor had a shop and whenever he ordered steel he would a couple of 12' lengths for me. Over a period of time I ended up with an assortment from 1/4" to 1". Since selling my BP and 12" lathe I only use up to 1/2". Though my projects now are small it would be nice to occasionally take deeper cuts. Very impressed with your belt sander conversion.
> Regards, Less



Good Morning, Less. I had a chuckle about the tool angles - who knows what proper angles are? We use what works for us, right? Still, I can tell you how I grind tools for mild steel, brass and aluminum and you can give them a try to see if it improves your current tool's performance. All tools have a general purpose shape.

Mild steel: 15 degree of side and end relief, 18 degrees side rake, 12-15 degrees of back rake. The back rake depends on where I want the cutting forces concentrated; less angle focuses the forces more toward the side cutting edge so it roughs better, more angle focuses them at the tip so it finishes better. The back rake is sufficient to augment side rake for efficient chip clearance in either case. Note that the relief angles are only moderately increased, while side rake is more than a mild steel tool will normally have; this is to reduce cutting forces primarily and cutting temps secondarily. This tool will take a 0.060" deep roughing cut on a little Sherline lathe. The lathe will moan but it won't groan or chatter, which is exactly what we should see when the lathe is used at max capacity. This same tool, when used on your Maximat 7, will walk through the same cut in mild steel without even slowing it down.
Brass: Side and end relief of 15 - 17 degrees, zero side and back rake. I have found that brass likes fairly large relief angles. I've gone up to 20 degrees of relief but found that the edge started to wear a bit too fast - brass is hard! I've also tried some rake on these tools and while 5 degrees of side rake seems to help a little, it isn't enough to spend the time to grind it. I do hone my brass tools often; sharp is good for brass. This tool will easily take a 0.050" deep cut on a Sherline lathe in brass. I tend to use smaller nose radii for my brass tools. I know that most guys use a large nose radius to improve the finish but I find 1/32 more than adequate for my needs.
Aluminum: Side and end relief = 15 degrees, side rake 18 degrees, back rake 40 degrees. Yeah, I know, 40 degrees of back rake! This produces a very positive rake cutter that will take a 0.100" deep cut in 6061-T6 on a Sherline lathe. Of course, very few of us waste material like that but it will make the cut. It will also give superb finishes because the back rake focuses all the cutting forces at the tip; all you need is a nose radius of 1/64 to 1/32" and it will produce a near mirror finish with a roughing cut and a mirror finish with a sizing cut and lubricant. I also find the back rake reduces or eliminates a built up edge; the chip is moving so fast and with so little heat that it just doesn't stick as long as I use some WD-40 on it. Give it a try and watch the chip flow right off the tip of the cutter.
I use 3/8" bits and use the same cutters on my Sherline and my Emco Super 11. They work well on either lathe. The mild steel and aluminum bits will easily take a 0.250" depth of cut on my 11" lathe and while I know they can go deeper, I don't need to waste material to find out how much deeper they will go.

Play with your lead angle with these cutters; there is a sweet spot for turning, roughing, finishing and facing.

I hope this helps, Less. It is always difficult to give hard numbers for things like a cutting tool. Wear, tool posts, usage differs from user to user but I hope these tools work as well for you.

Oh, and thanks for the compliment re the belt sander!


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## mikey

Okay, it sounds like we seem to agree that basic tools for lathe operations will work for most folks - a general purpose tool for turning/facing, a knife tool for facing and thin work and a standard 60 degree threading tool. For the general purpose tool, I am going to grind my Square Tool because it just works for most stuff we turn; you can easily modify the angles if that better suits your needs. 

I have the keystock in hand and have ordered some new belts so I'm ready to go. Now I need a volunteer to handle the distribution of these models. There will be three sets and there seems to be more than three guys who want to see them. Our volunteer would compile and track a list of folks to make sure nobody is missed and that the sets move along on a timely basis. I should think a week or two is enough for each guy; what do you think? So, if we can find a volunteer coordinator, everyone who wants to look at these things can PM him and he will keep track of things. As the maker, I would like to choose who gets the sets first. 

Anybody willing to step up?


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## Aukai

I do not have any blanks, or a lathe in hand, and will not be first on the list for sure. A PM list might get bulky, but doable. Another thread where the list can be discussed about who has the samples, and would be a head count. Then PM the address to who currently has it for next in line. Not sure how choosing where it goes next would be done. Thinking out loud.


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## Rockytime

mikey said:


> Good Morning, Less. I had a chuckle about the tool angles - who knows what proper angles are? We use what works for us, right? Still, I can tell you how I grind tools for mild steel, brass and aluminum and you can give them a try to see if it improves your current tool's performance. All tools have a general purpose shape.
> 
> Hi Mikey, WOW! Great dissertation! I am surprised at the severe angles. I printed it and am posting it in my shop. I use 1/4" on the Sherline and 3/8" on the seven inch. Gonna have fun trying these. BTW I covet your 11". I have a couple of friends with the MaxiMat11. Dynamite lathe. My 7" has the mid bed milling column but I don't use it as it is inconvenient. Again thank you so very much for your Information.
> Regards, Les


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## Z2V

Hi Mike 
If you are going to the trouble to make the tools I'd be more that happy to help if needed. 
Im very new to hobby machining and tool grinding so I'll take all the guidance I can get. Absolutely no offense taken.


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## mikey

Rockytime said:


> Hi Mikey, WOW! Great dissertation! I am surprised at the severe angles. I printed it and am posting it in my shop. I use 1/4" on the Sherline and 3/8" on the seven inch. Gonna have fun trying these. BTW I covet your 11". I have a couple of friends with the MaxiMat11. Dynamite lathe. My 7" has the mid bed milling column but I don't use it as it is inconvenient. Again thank you so very much for your Information.
> Regards, Les



You're welcome, Les. Let me know if I can help and I would love to hear how those tools work for you. I know the angles are different from what you're used to but its worth a try, right?

Yup, love my little Emco lathe. There are 11" lathes, and then there are 11" lathes!


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## mikey

Z2V said:


> Hi Mike
> If you are going to the trouble to make the tools I'd be more that happy to help if needed.
> Im very new to hobby machining and tool grinding so I'll take all the guidance I can get. Absolutely no offense taken.



Thanks for stepping up, Jeff, and welcome to the HM forum! You will like it here and we're happy to have you.

Okay, so Jeff will be the contact guy to get on the list to receive the tool sets. Please PM him to be included. First come, first served except I will choose who gets the sets first. From there, they will go out according to the order on the list. Just to be clear, the guy who has the set has to pay for flat rate USPS Priority Mail shipping to the next guy on the list. 

Let's decide how long each guy can keep the set. One week, two, more?

Jeff, I consider the names and addresses of the guys on the list to be private and privileged information and I'm sure you will agree that it should be kept on your computer and not remain on the HM server for all to see. When we have a list, send it to me via PM and I'll choose the first three.

Thanks for stepping up, Jeff, I appreciate your help.

Mike


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## Z2V

I'll populate the three lists in the order that I receive the PM request. 1st, 4th,7th go on list A, 2nd, 5th, 8th go on list B, 
3rd, 6th, 9th go on list C, you get the idea. After Mike chooses the first three recipients then  I will make the list in order received. I think a week would be long enough to study the tools and duplicate a set of your own. Let us know what you think. 
Mike, thanks again for doing this for all of us new to tool grinding and those who are not.
Let the PM's begin.


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## ttabbal

Thanks for coordinating! I'll have to get some stuff ordered so I can copy them.


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## ttabbal

So, to practice and copy these, I would want to get some 3/8" square keystock? I know I need real HSS to cut with eventually, but it sounds like the keystock is better for practice and cheaper as well.


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## Z2V

Key stock is most definitely cheaper and much easier to get.


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## Z2V

Guys, when you PM to get on the list please include an address. I will PM each of you when you will be receiving the models and I will include a name and address of who you will be forwarding them to when you are done. This should go  smoothly once we get rolling.
Thanks


----------



## mikey

ttabbal said:


> So, to practice and copy these, I would want to get some 3/8" square keystock? I know I need real HSS to cut with eventually, but it sounds like the keystock is better for practice and cheaper as well.



Mild steel keystock can be found in the hardware store. It is best to get the size closest to the tool bits you intend to work with on your lathe. Cut them into 3" long pieces so you get used to working with bit-sized pieces. Use some of them to reproduce the models but stick with them to practice grinding lathe tools until you can grind it exactly the way you want it. It takes a little while for your brain and hands to coordinate and keystock is much easier to grind than HSS and way easier to grind than cobalt. If you want your lathe tools to actually look like lathe tools, keystock is how you learn to do that.


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## Z2V

I have six members signed up already. Room for many more so spread the word.


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## Aukai

PM sent...


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## Z2V

Got you down Aukai


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## mikey

*HUMBLE PIE
*
I looked all over my shop and couldn't find my early lathe tools. I wanted to show them to you guys so you know that we all start at the same place and that there is a good chance that I hold the title for THE worst lathe tools ever ground. Anyway, I finally remembered (Oh yeah? Wait until you pass 65 years of age) that I might have given them to a friend who was going to grind over them and use them on his little Sherline lathe. This must have been over 20 years ago. It was a long shot but I called and asked if he still had any of them and he said he did. I arranged to pick them up tonight. He wasn't home (went out for dinner) but he did leave me this note:

*Mike, I never re-ground these tools (so don't blame me). I kept them to cheer me up whenever things got really bad in life; every time I looked at them they reminded me that things can always be worse! I have to admit that you really, really, really sucked at tool grinding back then and I cannot believe you would willingly show these tools to people on an international forum. Have you no pride? On the other hand, it may be useful to show them that one really can rise from the depths of total suckage so they shouldn't quit. Yeah, encourage them, okay? Just remember to take responsibility for these things now; DO NOT BLAME ME FOR THIS. 

Your lovingly kind, supportive and gentle friend,
Bonehead (not his real name but appropriately descriptive)
*
This is his actual note, verbatim! I swear, even I can't make up that kind of crap ... the depths of total suckage must be his idea of waxing poetic or something. Sheesh! In his defense, Bonehead grinds nice tools (but only because he learned from me in case he reads this).

Anyway, here are my earliest tools. I was trying to duplicate some tools from Sherline and not surprisingly, they caused severe chatter at small depths of cut (0.020" deep or less). You can see two brass tools with flat tops that were the beginnings of my general purpose shape and a knife tool before I knew such things existed.







I was really, really bad back then and I didn't understand a thing about tool geometry. What followed was over 5 long years of experimental tool grinding, reading and cutting trials. I made changes to each tool angle one at a time, measured the amperage changes to see if the changes I made in the grind reduced the power draw and logged everything on a floppy disc (subsequently lost when I moved to my current home). I know I ground nearly 300 experimental tools and somewhere in the process, I learned to grind a tool. I think I also began to understand tool geometry but I'm still working on that.

I am humbling myself here to show you that nobody enters this hobby with grinding skills. They develop over time and with a lot of practice. I can grind a really good tool in less than 5 minutes now but in the beginning, no, it took a lot of time and effort. 

Our little experiment here with the models will hopefully cut the learning curve down a bit. I'll share how the tools are ground and anything else I can think of to help you new guys learn to grind tools. It's worth the effort if it helps just one of you. I think Bonehead would agree that you cannot possibly suck at it worse than I did.


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## Aaron_W

This is a really nice gesture and a neat idea.

While having a physical piece to hold and look at is helpful I think just having good photos and explanations of the how and why would still go a long way towards learning how to grind these tools and come up with new tools as well. It will also remain available long after the models have been dispersed to whereabouts unknown.

Honestly I'm lost beyond LH and RH tools at this point, so I do hope you explain the other tools strengths and weaknesses. I haven't had any trouble with the included Sherline set, but I've only been working with aluminum to this point. I have ordered 10 or 20 tool (memory can be an issue for those of us under 65 too  ) blanks though to give me lots to practice with, so this is good timing.

Thank you


----------



## Aukai

I think this is a great opportunity, and very grateful to Mike for doing it. My plan is to get the key way material, and hopefully be able to make a very close copy of the examples to keep on hand. When I start having any issues from touching up, or a slight change in shape, I can see where I went wrong. And when I get old enough, maybe I'll get good at it.


----------



## mikey

Aaron_W said:


> This is a really nice gesture and a neat idea.
> 
> While having a physical piece to hold and look at is helpful I think just having good photos and explanations of the how and why would still go a long way towards learning how to grind these tools and come up with new tools as well. It will also remain available long after the models have been dispersed to whereabouts unknown.
> 
> Honestly I'm lost beyond LH and RH tools at this point, so I do hope you explain the other tools strengths and weaknesses. I haven't had any trouble with the included Sherline set, but I've only been working with aluminum to this point. I have ordered 10 or 20 tool (memory can be an issue for those of us under 65 too  ) blanks though to give me lots to practice with, so this is good timing.
> 
> Thank you



Thanks for the kind words and I'll be glad if the models and discussion here help you. 

You are right, Aaron. The "what, why and how" part of our discussions is what really matters. As we go along, if you are not clear on something then please ask. It is really easy for me to blow right past something basic without realizing it and unless you tell me that I did it, I won't know. My intent here is to clarify and I'm counting on you and the other guys to help me do that. 

As for being lost beyond RH and LH, I'm attaching some info that can actually be found elsewhere but I'll put it here for you so you can read it at your leisure. It will give you a basic understanding and we can fill in the blanks as we go along.

Stick with us. We are going to wake that little Sherline lathe up!


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## mikey

Aukai said:


> I think this is a great opportunity, and very grateful to Mike for doing it. My plan is to get the key way material, and hopefully be able to make a very close copy of the examples to keep on hand. When I start having any issues from touching up, or a slight change in shape, I can see where I went wrong. And when I get old enough, maybe I'll get good at it.



I'm sure the other guys on the forum will agree with me that it ain't the age, it's the mileage!


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## Aukai

HAHA I feel like this horse has been ridden pretty hard. OK back to our programing....


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## q20v

Hey Mike,

I'm in Canada and would love to take part in this, is that possible considering my location? I would happily reimburse the shipper some of the shipping costs, considering it would likely be more due to the border crossing. If not, I completely understand.

Many thanks,

Barry


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## Z2V

Good morning Barry

I'm going to be at the end of the list so if you don't mind the wait I'll send a set up to you and you can return them to me when you are done with them. That will be no problem. 
Send me a PM and I'll get them to you in time.

Jeff


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## q20v

Thanks Jeff, PM sent.

Barry


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## DHarris

Hey Jeff & Barry,

I would be happy to send a set up to Barry - Son and Daughter-in-law & grandkids there so used to the experience/costs involved.

No problems!

Dave Harris


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## Z2V

Dave

Sounds good to me. I'll send you PM and put Barry after you on the list.
Thanks

Barry
I'll PM you contact info that you can forward to when you are done.


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## Metal

As dumb as it sounds, I wouldn't mind some 3d models

I could 3d print them and send them out to new machinists for next to nothing, sure they won't be 100% accurate once printed but it should give people grinding their first tools a good idea of what kind of shape they are looking for in 3 dimensions


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## q20v

Dave,

Thank you very much! Please let me know if there's anything I can do to reimburse some of the extra expense you may incur.

Jeff,

Sounds good!

Barry


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## mikey

Metal said:


> As dumb as it sounds, I wouldn't mind some 3d models
> 
> I could 3d print them and send them out to new machinists for next to nothing, sure they won't be 100% accurate once printed but it should give people grinding their first tools a good idea of what kind of shape they are looking for in 3 dimensions



That would be awesome! Can you get on the list and model the tools? If there is a demand, you could send them out for a fee to cover all your costs and maybe a little bit for yourself. If I was a new guy and could buy something to keep, I would do it.


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## mikey

@Z2V, @DHarris , thank you for helping Barry out. I just love this place!


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## mikey

I just got notified that my new ceramic belts are shipping - finally. I get to review them for you here and that will be cool. Sorry it's taking so long but if you've ever had an old belt snap on you when your hands are next to them then you understand why I ordered new belts. 

I was speaking to Bonehead last night and he cracked up when I told him I posted a picture of my early tools and his note. In his typical sensitive manner, he said, "You mean that even after they saw how you grind tools, there is still interest?"


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## Dhector

Any chance a newbie guy on here that noone knows can get in on this? I'd even help out if possible. I have some unground tools that I could send out to someone for the cause. Thank you all.


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## Aukai

Metal, if you go through with the idea of 3D printing I would like to be on that list also. Let me know the costs associated when you are ready.


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## mikey

Dhector said:


> Any chance a newbie guy on here that noone knows can get in on this? I'd even help out if possible. I have some unground tools that I could send out to someone for the cause. Thank you all.



Heck yeah, you can get in on this. PM @Z2V and ask him to put you on the list.

Love your avatar pic, by the way!


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## Dhector

mikey said:


> Heck yeah, you can get in on this. PM @Z2V and ask him to put you on the list.
> 
> Love your avatar pic, by the way!



Cant remember where I robbed the pic on the net from but I couldn't pass it up!!!! I love it!!!!

I did PM him right before the post. He hasn't even had time to reply to me honestly before my post here. I just wanted to throw out there that Id be willing to donate some tools if it would help the cause. This machining stuff is cool and I tend to purchase for the future(to an extent) in case I ever figure out how I need to do things. Probably spend more that I should but why do I have a job in the first place, right!!  I also got a box of stuff from the estate where my lathe came from and it got all sorts of tools already ground so i may not need the uncut ones I bought for several years honestly. Anyway without writing a book the offer is open if it appeals! Thanks.


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## darkzero

This is a great thread to help beginner grinders! I sure could use the guidance as well! Thanks to Mikey & all those who are participating in this!

I'll make this thread a sticky for a while.


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## Z2V

Dhector

You are on the list. PM sent with info

Jeff


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## Metal

I am absolutely game with putting you guys on "a list"  I can probably do it for like 5-10 bucks tops as long as USPS will take them in a normal envelope.

However Ive started turning "parts" as of... like 2 weeks ago, so I wouldn't be a good person to 3d model these since I've only ground one tool poorly so far, lol 
If anyone wants to send me a set of properly ground tools I could model them and send them back though.


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## Z2V

Metal
i will be glad to add you to the list if you PM me contact info.

Jeff


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## dlane

metal , Do What, I'll pass


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## Randall Marx

I would love to get on the list, but I want to get my grinder set up with decent rests first.
Metal: What type of 3D models can you use? I have access to Solidworks and could model them for you, based on Mike's pictures and descriptions, if that would help.
-Randall


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## Metal

Randall Marx said:


> I would love to get on the list, but I want to get my grinder set up with decent rests first.
> Metal: What type of 3D models can you use? I have access to Solidworks and could model them for you, based on Mike's pictures and descriptions, if that would help.
> -Randall



Yeah solidworks, fusion, really any format would work that is object based


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## mikey

I finally got my ceramic belts in and gave it a try on mild steel keystock and ... it ate my keystock! I bought the coarsest grit, 36 grit, and 80 grit belts from Red Label Abrasives: https://www.amazon.com/gp/product/B00H8YWLNU/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

These ceramic belts are stearate-coated to reduce material build up and this allows it to run cooler. I applied some stick wax anyway and proceeded to grind the keystock. The 36 grit cuts very aggressively for the first few passes across the face and then it settled down and felt smoother. I assume I am knocking the tops off the ceramic crystals and when they're sort of level, the grind settles down to a smoother cut. I am used to using a 24 grit Alum. Oxide belt and this 36 grit belt is way more aggressive than the AO. It chewed through the mild steel like it was aluminum, and I cannot see any evidence of wear after grinding one bit. 

I switched to the 80 grit belt for a second pass to clean up the coarse grind marks left by the 36 grit belt and the finish left by the 80 grit belt looks like the finish left by my 24 grit AO belt. This ceramic stuff cuts faster and much more aggressively than AO and now I realize that I should have ordered 60 grit for shaping and 120 or finer grit for finishing. I will re-order new belts later but will make do with what I have so I can get the model tools done. I have to say that I am impressed!

I will need to grind some HSS with this belt to see what that is like but I suspect these ceramic belts will very likely become my preferred belts once I figure out the grits. They cut fast, cool and are pretty economical for what they are. I am anxious to grind a tool for aluminum to see if this belt will cut the back rake angle better than my AO belts do. My aluminum tool has 40 degrees of back rake and this tends to push the belt back onto the platen, leaving a curve on top of the tool. While the tool works well, the back rake looks funny. If these belts cut instead of push on the belt then I may just be able to grind a more accurate tool after all. We'll see. 

I'll do a follow up report on these belts after I have a chance to grind a HSS tool. I'll start work on the model tools tomorrow and then they'll be on the way - hang on, guys!


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## Z2V

Thanks for sharing that with us Mike. I'll give he's strong consideration for the 2x72 I'm making.


----------



## mikey

Z2V said:


> Thanks for sharing that with us Mike. I'll give he's strong consideration for the 2x72 I'm making.



It cuts like crazy on my little 2x42. I can only imagine what it would be like using a 1-2hp motor and having 72" of ceramic belt running around. It would probably take you just a few minutes to crank out a lathe tool.


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## Aukai

Sounds impressive.....


----------



## mikey

Aukai said:


> Sounds impressive.....



The belts can handle mild steel, which isn't saying that much. We'll see how they do with a Rex 95 blank. If they eat that, too, then I'll really be impressed. I'm liking them so far, though.


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## Randall Marx

Sorry I've been away for a few days, but will start on solid models soon...possibly at lunch today. I think this is a GREAT idea for all that are involved and thank all who are helping!


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## Metal

Randall Marx said:


> Sorry I've been away for a few days, but will start on solid models soon...possibly at lunch today. I think this is a GREAT idea for all that are involved and thank all who are helping!


I ordered some filament for this on monday
All proceeds beyond costs will be donated to HM


----------



## Randall Marx

Update: I think I got the Square tool done, but will attempt to include a picture to make sure it conforms to Mike's design. I included no dimensions, but gave the classic 3-view drawing. All relief and rake angles are 15 degrees and both radii are 1/64". Mike, please let me know if this is right. If so, I'll get the other two done and models sent to Metal so he can try the 3-D printing.


----------



## mikey

Randall Marx said:


> Update: I think I got the Square tool done, but will attempt to include a picture to make sure it conforms to Mike's design. I included no dimensions, but gave the classic 3-view drawing. All relief and rake angles are 15 degrees and both radii are 1/64". Mike, please let me know if this is right. If so, I'll get the other two done and models sent to Metal so he can try the 3-D printing.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> View attachment 242086



Looks good to me, Randall. It might be an idea to wait until you get the model because for this project I made the side cutting edge angle a bit smaller to give more mass at the tip. The reason is that I don't know who will use it and how they'll use it. This small change of a few degrees will add a lot more strength to the tip.

I am done with the models ... almost. I was done but then I tried to make the square tools look pretty by honing off the grinding marks with a diamond stone. The material is so soft that this changed the geometry of the tool! I had to go to the hardware store for more keystock and should be able to get the square tools done today. I'll just deburr them and then I can get them in the mail. Sorry this is taking so long, guys.


----------



## Randall Marx

Hi Mike
Do you mean that the first grind is less than 60% or that the relief angle is less? If I have a good description, I can work from that unless you _really_ think I need to wait. I put this one together from your article that you wrote on machinistblog (which I found to be quite informative and gave me a better idea of what the angles all do).
Thanks for the input and thank you VERY much for the great idea and effort.
Randall


----------



## mikey

Randall Marx said:


> Hi Mike
> Do you mean that the first grind is less than 60% or that the relief angle is less? If I have a good description, I can work from that unless you _really_ think I need to wait. I put this one together from your article that you wrote on machinistblog (which I found to be quite informative and gave me a better idea of what the angles all do).
> Thanks for the input and thank you VERY much for the great idea and effort.
> Randall



The side cutting edge angle is slightly less than I normally make it. The tool will look very much like the one in the How to grind a HSS tool article on HM. In fact, it will be almost identical to that one. My best advice? Wait for the tool or wait until you see the write up so you don't have to do it twice. I would hate to have you and Metal go through the trouble, only to have it not be the way the models are.

I think this project has to potential to help more people and if it does then its worth the effort. Grinding the tools is no effort. Writing them up is where the work is and I'm getting to that.


----------



## mikey

Well, I got the models done and they are ready to ship tomorrow. From left to right, a general purpose Square Tool, a general purpose Knife Tool and a 60 degree threading tool:










I am going to write these tools up but it is going to take me some time to do that. I ask for your patience as I do this. I will try to post my comments as I complete them in parts. You can follow along, correct me, ask questions and I'll do my best to keep up. By the time we're done, you should have what you need to reproduce these tools in HSS. 

Each tool is proven to work as intended. None of them are ground to conventional angles. Instead, they are ground to cut with lower cutting forces and temperatures, which should allow them to cut deeper, size more accurately and finish finer on a smaller hobby class lathe. If you would prefer using conventional tool angles then just use the values found in the typical angle table. In fact, it would be a good idea at some point to grind a tool with conventional angles and compare it to a modified tool like those above and see what the differences are. Do the same with those tools and your carbide tools. You will quickly find which tool works best in the different materials you work with and will then know which tool is the best one for the job at hand. Personally, I don't believe that you should use only HSS or only carbide; I think you should use the right tool for the job and you cannot do that unless you can grind a good HSS tool. Then you have options, right?

Anyway, the tools will go out as soon as I can post them and then I'll get to writing.


----------



## Aukai

Thank you for all of the effort, in my humble opinion this is huge.


----------



## mikey

Aukai said:


> Thank you for all of the effort, in my humble opinion this is huge.



Thanks for the kind words, Aukai. You guys are worth the effort.


----------



## Z2V

Heads up to all you guys and gals in Canada, we have a set of model tools headed up your way so get your name on the list!!!
Send me a PM with your contact info and I'll get a set coming your way.

Jeff


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## q20v

Jeff, I'm assuming you got my PM last week? Just don't want to miss out on this opportunity!

Thanks Mike and Jeff for setting this up for everyone. It is greatly appreciated!


----------



## Metal

Hey mikey, can I have a picture of what your jig setup looks like to grind these?


----------



## burtonbr

I would be very interested too. I would be in on "borrowong" them for inspection if that is they only way but if I could buy a set to keep for reference that would be even better .


----------



## Z2V

Good morning burtonbr
Get yourself some cheap key stock from the hardware store and make yourself copies to keep the send the models on to the next person on the list.


----------



## Z2V

Q20v
Yes, I have you on the list and that is why I made the above post. They will be coming your way shortly!!!


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## q20v

Great, thanks Jeff!


----------



## Metal

Made a quick jig to go with the 3dp examples, what other angles do we need?


----------



## mikey

Metal said:


> Hey mikey, can I have a picture of what your jig setup looks like to grind these?



I don't use any jigs. I don't need them and neither do you. I'll show you exactly how these are ground and you'll see why I say that. In fact, if you can draw a line and grind to that line then you'll be fine.

These tools are simple turning tools that are very, very easy to grind. Don't worry, you can do this.


----------



## mikey

The models are done and will be on their way to the first three recipients shortly. I just wanted to give a preliminary explanation of what each tool is and does. We will go into each tool in much more depth very shortly.

They are made of mild steel keystock and I was reminded how soft this stuff is when I tried to hone the faces of the square tool. I was able to remove all the grind marks but I totally changed the geometry of the tool in the process! So, out those went and I ground new square tools. This time, I merely deburred each tool and put a nose radius on them so expect to see grind marks and bare keystock surfaces but at least the geometry will be accurate. When you grind one of these tools from HSS you can hone the faces without altering the geometry much at all. Please note that while the models are not honed, the edges are quite sharp so handle them carefully.

*NOTE:* Tool grinding can be dangerous and I encourage you to use eye, lung and hearing protection. Grinders, both wheel and belt, can eat your hands in an instant so stay focused and know where your hands are at all times. Inspect your grinding tools and be sure they are in good and safe working order. Do this at your own risk and please don’t blame me if you get hurt in the process.

Okay, let me tell you about the model tools in the set. There are four basic lathe operations: turning, facing, threading, and making holes (drilling/boring). Of course, there are many variations of these basic tasks but the point is that your tools will allow you to do most basic lathe work.

From left to right we have a general purpose right hand Square Tool, a general purpose RH Knife Tool and a 60° threading tool. All these tools are proven to work as intended and all are simple to grind. We’ll discuss each of these tools in more detail as we go along.




·      *Square Tool:* I call it “square” because the two relief and two rake angles are the same - 15°. You can just call it a right hand turning tool, meaning it cuts toward the chuck. A left hand tool will be a mirror image of this tool and will cut toward the tailstock.

I made this model tool with a 2° smaller angle at the side cutting edge than my usual square tool has (ie; 7° on the model vs 9° on my usual tool). Below is my tool on the left, your tool on the right.





This is because many of you will use this tool to rough with and this smaller angle provides more mass at the tip to handle higher cutting loads. This does not alter the performance of the tool. You simply need to alter your lead angle a bit more in use and it will work exactly the same as my tool. If you insist on making yours the same as mine, I will tell you how to do it when we discuss grinding it.

I put a ~1/64” nose radius on this model. That is usually sufficient for most work but if you prefer, you can enlarge your nose radius to whatever you like. For roughing, however, a smaller nose radius is preferred. Besides, this thing has 15 degrees of back rake and that helps produce a nicer finish so don’t go overboard with large nose radii. Large nose radii increase radial cutting forces (we'll go into cutting forces superficially at a later date) and increase deflection. On a 3/8" turning tool, Machinery Handbook recommends a 1/64" radius Max. I listen to that, mostly, but do go up to 1/32" when I feel I need it.

This tool will turn, face and chamfer. The 80° angle at the tip will allow the tool to turn into a shoulder without rubbing and then face out without rubbing, all without changing the lead angle of the tool.

o  When facing the end of a work piece, the tool is angled so the cutting point of contact is just aft of the tip, at the forward area of the side cutting edge.

o  When turning, the angle of the tool will vary with the operation; more perpendicular to the work for roughing and slightly angled toward the tailstock for finishing. This is called changing the lead angle of the tool and has been discussed elsewhere. If we need to clarify it further, please comment so we can do that. You need to try different angles until you find what works for you; there is a sweet spot for turning but it depends on the operation – roughing, sizing or finishing.

o  When chamfering, use the edges near the tip of the tool to chamfer outside corners or inside a bore; just angle the tool to cut with the side or end and slow your speed a little because you’re using it as a form tool so cutting forces are higher. Bring the tool into contact and gently feed it into the work with your cross slide and it will chamfer as well as a purpose ground chamfering tool.

The relief and rake angles on the tool are a compromise that allows it to work with multiple materials; mild and medium carbon steels, stainless steel, aluminum, brass and most plastics. While the tool is not optimized for these materials it will cut all of them rather well. This tool will also cut harder materials like tool steels (O-1, etc.) and harder steels (1144, 4140, etc.) but it is better to alter the tool angles to optimize the tool for these materials and use a cobalt or tungsten bit, or use carbide if that is available. Don’t worry; I’ll tell you how to alter the angles.

The angles on this tool allow it to cut with significantly lower cutting forces and temperatures than a standard tool. This means that it will allow a light lathe to rough deeper, size more accurately and finish finer (than it would when using a conventional tool) before running into the power and rigidity limits of your lathe. It also means the tool will deflect less; if you can dial in a 0.0005” deep cut, the tool will usually cut it.

This tool will be used for most work on your lathe. If you choose, you can optimize the angles on the tool to work with a specific material group but the overall shape of the tool can remain the same.

·      *Right Hand Knife Tool:* This is a kick ass facing tool. Like all facing tools, this one cuts at the side cutting edge up close to the tip. Because all the cutting is at the side edge, the nose radius does not participate much at all and can be small; this allows you to go into the corner of a shoulder and face out without leaving a huge radius at the root/corner. The side relief angle is 15° so it takes light or heavy facing cuts easily. The back rake is more conservative and this focuses the cutting forces toward the side cutting edge, which is what we want with a facing tool.

This tool will also work as a thin work finishing tool. All turning tools will deflect thin work pieces and that makes turning a consistent diameter a challenge. This tool is ground to a somewhat delicate tip and is able to take whisper-thin sizing cuts with minimal deflection. I have turned a taper-free piece of brass that was 1” long and only 0.050” OD and cut it without a taper over the full length with this tool. Although the tip seems delicate, this tool is very stiff and will face accurately.

This is also a really good chamfering tool for both inside and outside edges.

Note that due to the conservative rake angles, pointed tip and small nose radius (~1/64”), this tool does not turn well on longer work. It tends to inscribe a spiral pattern in the work surface so don’t use it for general turning unless you enlarge the nose radius.

My personal knife tools are made of cobalt steel because it holds an edge for a very long time. My tool for steels is about 15 years old as of this writing and it is as good as the day it was ground. It is gently honed after each use. Try one; you will like it.

·      *60° Threading Tool:* This is just a normal threading tool except it is ground with 15° relief angles on each side. The top is flat (zero rake) but is honed. There is a tiny flat stoned into the tip; this prevents breakage of the tip and flattens the root of the thread a tiny bit.

The cutting tip is offset to the left to allow the tool to thread up close to a shoulder. When you grind your threading tools, use a fishtail gauge like a Starrett C391 or similar tool as an angle template. You must have a 60° included angle at the tip, not more, not less; precisely 60°. Then stone a tiny flat at the tip and hone the tool so it is razor sharp.

The model’s shape allows it to cut threads fairly close to a shoulder. If you need to cut even closer, grind the left side tip angle closer to the tip of the tool; this moves the tip further to the left. The tool, as is, will cut a 4-40 thread on up to ¾-16 and any 60° thread in between. It may go smaller or larger but I haven’t done that yet so I cannot say for sure.

I have found that a 15° relief angle cuts really accurate threads because it lowers cutting forces. Standard relief angles are in the 10-12° range or less and when cutting coarse, deep threads I can hear the tool cut. This tool just hisses and produces threads with almost no fuzz or burrs. It works for me; you might give it a try.

So, these are your tools. I will tell you how to grind and modify each tool in sequence as I write them up. Don't worry; all are really simple to grind. The shape of the tool is what you see but the angles of the tool faces are what really matters. I will show you how to grind the shape but what I really want you to understand is the *what* and *why* behind the angles on each face. Get that, understand that, and you will be able to make your tool do almost anything you want the tool to do.

Before I forget, each tool is meant to be used at center height. Make yourself a height gauge and use it whenever you use a tool, even if it is already in a quick change tool post holder. If you want your tools to work as they should, get them at center height.


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## Aukai

Awesome read, thanks for taking the time.


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## mikey

I just realized that the guys who get the model tools first may need to know how they are ground in order to reproduce them. I’m going to cover that as we go along but they will need the grinding info first, so here it is.

*Turning Tool*

First, align your tool rest to 15°. You can use the angle on the side of the tool to get this angle. If you have one, you can set it more accurately with a digital angle gauge. Measure ¾” down on the left side of the blank and put a mark. Then measure 1/8” across the tip and mark. Now connect the dots with a line. (If you want your model to match my HSS tool, mark it at 3/16” across the tip, mark it and then grind it.)






Now just grind to the line. This produces the side cutting edge angle. If this were a left hand tool, you would do the same on the right side of the bit.

Once the side angle is ground, use a protractor set to 10 degrees and put the base of the protractor on the side cutting edge and mark the angle.





Then grind to the line and you’ll have this.




Next, we need to grind the rake angles. Measure ½” from the tip and mark the side of the tool. Then put a line on your tool rest, up near the belt or wheel, with a 15° angle like this:




Keep the shank of the tool aligned with the line on the rest and the back of the blank flat on the rest at all times. Now bring your push block into contact with the tool and just push the tool straight into the belt/wheel. It will cut the rake angles all at once. Watch the contact point on the tool and as it just reaches the tip, stop. You should have this:






*Knife Tool*

You are going to grind the side relief angle on the side of the tool first. It is 15° so you don’t need to change your table angle. Mark ¾” down from the tip (you can actually measure ½”; you don’t need so much cutting surface) and place the side of the tool parallel to your belt/wheel. Bring your block into contact with the blank and do a straight steady push into the grinder until the grind reaches the top edge of the tool and stop.




Use your protractor and set it at 60-70°. I set mine to 65° and made a mark from the tip:




Now just grind to the line. The table angle stays the same. You should have this:




Now you need to do the rake angles. On this tool, the side rake remains at 15° so the table angle remains the same but the back rake is reduced to 10° so re-draw the line on your tool rest at 10°. Mark the side of the tool at ½” from the tip and align the tool shank with your mark on the rest and push straight in to cut the rake angles. You should have this:






*Threading Tool*

Set your protractor to exactly 30°. On my Starrett protractor, exactly 30° means I need to split the 30° line with the side of the moveable arm. Mark the blank somewhere up near the tip and grind it to the line.





Re-set the protractor to exactly 30° the opposite way, align the arm to the tip end of the first cut and mark. Then grind to the line:





This should give you an accurate 60° included angle at the tip of the tool and it should align exactly to your fishtail:




Note: if you wish the point of the threading tool to be closer to the left side, do it by aligning the protractor arm lower than the tip of the tool. When you grind to that lower line, it will produce a pointed tip closer to the left side. You might be able to get 0.050” closer this way so keep it in mind if you need to get up close to a shoulder.

That’s it, you’re done. See? It’s easy! But don’t get cocky. Mild steel keystock grinds like butter; HSS does not, and cobalt and tungsten are worse. Just kidding; tool steel does take more effort to grind accurately but the process is basically the same. Follow these instructions to reproduce the models but you can change the shape in any way you choose, provided you know why you’re changing it and understand what the result will be.


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## Z2V

Great write up Mike, this is going to be a great learning experience, thanks for your interest in sharing this with us.


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## mikey

Z2V said:


> Great write up Mike, this is going to be a great learning experience, thanks for your interest in sharing this with us.



Thank you, Jeff. Yeah, I hope this helps. We're going to discuss each tool in detail next. How to grind it in more detail but also why we're grinding it the way we are, and how we can change the angles we grind to achieve the results we want. By the time we're done you should have what you need to make a lathe tool cut just the way you want it to.

By the way, I know I'm making this whole grinding thing look easy and simple. If you follow the instructions above, it is pretty easy but it's going to challenge some of you. Take your time and grind on keystock until you can get every angle exactly the way you want it. Then, when you grind a HSS tool bit, it WILL be easy.


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## mikey

I was asked by one of the guys to clarify "lead angle". While this is a really basic thing, I remember being concerned/confused when I started so let's see if we can make it clear.

The lead angle of a tool is an actual physical feature on the tool. When the tool bit is perpendicular to the work piece, the lead angle is equal to the side cutting edge angle. The side cutting edge angle is the first face you grind on a tool, on the left side; it holds the cutting edge. This angle is not random. Old style turning tools had different angles to suit their purpose. Roughers had less angle, finishers had more angle and facing tools were somewhere in the middle. On a newer style general purpose tool like our Square Tool, the side cutting edge angle is greater than a rougher but less than a finishing tool; it can actually be anywhere between these two but it will be closer to a rougher for general use because the tool will be subjected to high cutting loads.

Lead angle is also variable on the general purpose tool because we can easily position it wherever we like. You will find that the tool roughs better when the shank of the tool is perpendicular to the work:




It sizes better (on the left) and finishes better (as on the right) when the side cutting edge is angled toward the tailstock.





So, when roughing you would turn the side edge more towards the chuck and when finishing you would turn it towards the tailstock. When you face, you would angle the tool just like a facing tool would be:




When you cut into a shoulder, the clearance angles ground into the tool allow it to turn into the shoulder and then face out:




Why does lead angle matter? Because it alters cutting forces. As the tool turns toward the chuck, forces decrease. As the tool turns toward the tailstock, forces increase. This happens because more of the side cutting edge comes into contact with the work as you turn the tool toward the tailstock. Turn it enough and the tool can chatter. If this happens, reduce the angle of the tool and chatter will resolve.

Similarly, when making heavy roughing cuts it helps to reduce the lead angle. Start with the tool shank perpendicular to the work but if it chatters, turn the cutting edge a bit more toward the chuck.

So, why should you even bother turning the tool towards the tailstock if it just increases cutting forces? Because it significantly improves finishes.

Can you use a negative lead angle? Yes, you can, and you will when you turn into a shoulder and face out. You are cutting with the nose radius but the tool will cut fine as long as you go at least 1/2 the nose radius or more for your depth of cut.

The bottom line is that each function - roughing, finishing and facing has it's sweet spot or angle; you need to find it. Play with the angle of your tool and when it cuts easily and smoothly, you've got it. I almost always start roughing with the shank of the tool angled just slightly back toward the tailstock and reduce the angle if it chatters, which it rarely does. When sizing or finishing, I angle it back toward the tailstock and if it chatters, I reduce the angle. I pretty much know which angle I need so I rarely get any chatter; you will get to this point, too.

PS: by the way, the threads on this 1144 Stressproof tool post stud was cut with a threading tool exactly like the model tool you will have.


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## Aukai

mikey said:


> I was asked by one of the guys to clarify "lead angle". While this is a really basic thing, I remember being concerned/confused when I started so let's see if we can make it clear.
> 
> The lead angle of a tool is an actual physical feature on the tool. When the tool bit is perpendicular to the work piece, the lead angle is equal to the side cutting edge angle. The side cutting edge angle is the first face you grind on a tool, on the left side; it holds the cutting edge. This angle is not random. Old style turning tools had different angles to suit their purpose. Roughers had less angle, finishers had more angle and facing tools were somewhere in the middle. On a newer style general purpose tool like our Square Tool, the side cutting edge angle is greater than a rougher but less than a finishing tool; it can actually be anywhere between these two but it will be closer to a rougher for general use because the tool will be subjected to high cutting loads.
> 
> Lead angle is also variable on the general purpose tool because we can easily position it wherever we like. You will find that the tool roughs better when the shank of the tool is perpendicular to the work:
> 
> View attachment 242223
> 
> 
> It sizes better (on the left) and finishes better (as on the right) when the side cutting edge is angled toward the tailstock.
> 
> View attachment 242226
> View attachment 242227
> 
> 
> So, when roughing you would turn the side edge more towards the chuck and when finishing you would turn it towards the tailstock. When you face, you would angle the tool just like a facing tool would be:
> 
> View attachment 242224
> 
> 
> When you cut into a shoulder, the clearance angles ground into the tool allow it to turn into the shoulder and then face out:
> 
> View attachment 242225
> 
> 
> Why does lead angle matter? Because it alters cutting forces. As the tool turns toward the chuck, forces decrease. As the tool turns toward the tailstock, forces decrease. This happens because more of the side cutting edge comes into contact with the work as you turn the tool toward the tailstock. Turn it enough and the tool can chatter. If this happens, reduce the angle of the tool and chatter will resolve.
> 
> Similarly, when making heavy roughing cuts it helps to reduce the lead angle. Start with the tool shank perpendicular to the work but if it chatters, turn the cutting edge a bit more toward the chuck.
> 
> So, why should you even bother turning the tool towards the tailstock if it just increases cutting forces? Because it significantly improves finishes.
> 
> Can you use a negative lead angle? Yes, you can, and you will when you turn into a shoulder and face out. You are cutting with the nose radius but the tool will cut fine as long as you go at least 1/2 the nose radius or more for your depth of cut.
> 
> The bottom line is that each function - roughing, finishing and facing has it's sweet spot or angle; you need to find it. Play with the angle of your tool and when it cuts easily and smoothly, you've got it. I almost always start roughing with the shank of the tool angled just slightly back toward the tailstock and reduce the angle if it chatters, which it rarely does. When sizing or finishing, I angle it back toward the tailstock and if it chatters, I reduce the angle. I pretty much know which angle I need so I rarely get any chatter; you will get to this point, too.
> 
> PS: by the way, the threads on this 1144 Stressproof tool post stud was cut with a threading tool exactly like the model tool you will have.



Just as good as community college, or at least a good prep for it maybe.


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## Aaron_W

In some places you use firm measurements, 1/2", 3/4". You are working with 3/8" stock, will these measurements need to be adjusted if I am reproducing these with 1/4" stock?


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## mikey

Aaron_W said:


> In some places you use firm measurements, 1/2", 3/4". You are working with 3/8" stock, will these measurements need to be adjusted if I am reproducing these with 1/4" stock?



Good question, Aaron. Just scale it down proportionally. The side and end cutting edge angles do not need to be precise. When I grind tools, I don't measure anything or use lines. I used them here so other folks are able to reproduce the models. It isn't that shape is not important; it is. But you do not need to be precise about the shape. The angles are another thing and that you do need to get right.


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## Dhector

This is a very good read!!! Thank you for all of this!!!!


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## Randall Marx

Thank you for the write-up on grinding these tools, Mike. Your articles and long posts are always informative and written in an easy-to-follow format, which I appreciate very much. 
I can use this info to accurately model the samples you have ground for us so I can get the models to Metal for 3D printing.
Thanks again for all your work done for our benefit!
Randall


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## Fallriverbryan

I have been reading but not contributing.  Could we get an update on the length of the waiting list? If it would be possible to add inside and outside radius tools, that would be great. Thank you for all the effort and great information. 

Sent from my SM-G950U using Tapatalk


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## mikey

At this point, I realize I’m doing a complete brain dump on tool grinding. By the time I’m done with this you guys will know what I know about the subject. Some of you may be wondering what brought this on. 

I suddenly lost my best friend a few years ago and it broke my heart. We were supposed to grow old together, going fishing and telling each other lies. He was a master cabinetmaker with so much to give, so much to teach but he never got the chance. Now I realize that none of us knows how much time we have; I’m not that old yet but my friend was 12 days younger than me so you never know. So I am passing on the information I have while I have the chance. I truly do appreciate the HM community and I cannot think of a better bunch of guys to pass this stuff to. If it helps you then I’ll be happy but I also hope it makes my friend happy to know that I did what he could not.


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## mikey

Fallriverbryan said:


> I have been reading but not contributing.  Could we get an update on the length of the waiting list? If it would be possible to add inside and outside radius tools, that would be great. Thank you for all the effort and great information.
> 
> Sent from my SM-G950U using Tapatalk



Bryan, I'm sure @Z2V will be able to update you on the list. I don't know what you mean by inside and outside radius tools. Can you give us more info?


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## Z2V

I currently have fifteen people signed up. Mikey is making three sets so I have five names on each list. We are looking at probably about a week per person.

Bryan, send me PM and I'll get you added to to list.

Joe P, I have you down, I forgot to PM you confirmation,

Thanks to all
Jeff


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## Joe P.

Z2V said:


> I currently have fifteen people signed up. Mikey is making three sets so I have five names on search list. We are looking at probably about a week per person.
> 
> Bryan, send me PM and I'll get you added to to list.
> 
> Joe P, I have you down, I forgot to PM you confirmation,
> 
> Thanks to all
> Jeff



Yep I got it, looking forward to it. Thanks. 


Sent from my iPhone using Tapatalk


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## Fallriverbryan

mikey said:


> Bryan, I'm sure @Z2V will be able to update you on the list. I don't know what you mean by inside and outside radius tools. Can you give us more info?


I work in stainless. USDA requires 1/4 inch radius on machined parts for cleaning purposes. That requires a round headed cutter to eliminate 90 degree angles in cut. I grind the profiles off hand but suck at it. Hope the pics work out.
	

	
	
		
		

		
			











Sent from my SM-G950U using Tapatalk


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## Metal

Got the 3d models, labeled the angles (because why not?) and will print a test part in a few hours
if the lettering comes out well which they should, i'll put some further instructions on the sides so after you do a few you dont have to keep looking up the exact distances and angles


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## mikey

Fallriverbryan said:


> I work in stainless. USDA requires 1/4 inch radius on machined parts for cleaning purposes. That requires a round headed cutter to eliminate 90 degree angles in cut. I grind the profiles off hand but suck at it. Hope the pics work out.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Sent from my SM-G950U using Tapatalk



I can see the pics but only by replying. There is some info somewhere on the board that helps when posting pics with Tapatalk. Maybe they'll show up in this reply when I post it.

You are talking about form tools and the one you want has a huge contact point. In addition, you are working with stainless steel that is not particularly hard but can quickly become so when its worked. The problem we have here is that a form tool has no rake angles so we can't make it cut easier or reduce cutting temperatures. About all you have left are to try increasing the relief angle and maybe add back rake.

Here is what I would try. I would use a cobalt tool blank. Grind the tool to the shape you need but use a relief angle of about 13-15 degrees all around the tool's edge. I would give it about 10 degrees of back rake to start and see how it works. Keep your cutting speed low and keep the tool cutting continuously with a positive feed. If you're allowed, use sulfur-based cutting oil. I will admit that I haven't made a tool like this before but if I had to, this is where I would start.


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## Z2V

Hey Guys
I just went in the garage and made a tool based off what Mike has already posted and I can say this tool cuts better than anything I have used on my little Craftsman lathe. I was able to make deeper cuts than before and with a much better finish. And this was my first try at doing it Mikes way!! I might try his knife tool latter this evening also.
Thanks Mike!!


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## mikey

Z2V said:


> Hey Guys
> I just went in the garage and made a tool based off what Mike has already posted and I can say this tool cuts better than anything I have used on my little Craftsman lathe. I was able to make deeper cuts than before and with a much better finish. And this was my first try at doing it Mikes way!! I might try his knife tool latter this evening also.
> Thanks Mike!!



Impressive, Jeff! Most guys have trouble grinding rake angles but you did it perfectly. I wonder if I could have done a better job myself!

Glad the tool works for you. Interesting what a few more degrees of angle can do, eh?


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## Aaron_W

mikey said:


> Good question, Aaron. Just scale it down proportionally. The side and end cutting edge angles do not need to be precise. When I grind tools, I don't measure anything or use lines. I used them here so other folks are able to reproduce the models. It isn't that shape is not important; it is. But you do not need to be precise about the shape. The angles are another thing and that you do need to get right.



Thank you, it just had me wondering since the pre-made tools I have don't go much beyond 1/4" of cut away except for the boring bar.

Trying to absorb your instructions, there is a lot there. You are doing a good job explaining though, I think when I finally have the chance to try this myself in a month or two it will make even more sense to me.


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## Metal

3dp examples came out good, they aren't 100% accurate but the labels turned out readable and give a good idea of what the finished product should look like

well they would be at least if I didnt print them in black, hah.


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## Z2V

I was able to make the knife tool tonight and I can say it delivered as promised. These tools have both been really easy to grind.  Following Mikes directions, I don't see how I could screw it up. I wanted to make the threading tool also but just as I was finishing the knife tool a bearing in my bench grinder started raising all kinds of hell. I'll fix that Monday. 
I'm supposed to be selling my lathe in the morning and was wanting to provide the new owner with a set of these tools. I guess two out of three will have to work for him. 
I've tried a few times to grind tools freehand with miserable results. I made myself a good adjustable tool rest for my grinder and that made all the difference.


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## mikey

Z2V said:


> I was able to make the knife tool tonight and I can say it delivered as promised. These tools have both been really easy to grind.  Following Mikes directions, I don't see how I could screw it up. I wanted to make the threading tool also but just as I was finishing the knife tool a bearing in my bench grinder started raising all kinds of hell. I'll fix that Monday.
> I'm supposed to be selling my lathe in the morning and was wanting to provide the new owner with a set of these tools. I guess two out of three will have to work for him.
> I've tried a few times to grind tools freehand with miserable results. I made myself a good adjustable tool rest for my grinder and that made all the difference.



Jeff, I have to show Bonehead your post. He told me that, "... suck is contagious, you know ..." but now I have proof that isn't! Glad it worked out. 

Please keep us posted.


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## Aukai

mikey said:


> Jeff, I have to show Bonehead your post. He told me that, "... suck is contagious, you know ..." but now I have proof that isn't! Glad it worked out.
> 
> Please keep us posted.


Good job, hope to be able to do as well. Yeah, yeah, OK what else is on the lift, besides the tool?


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## Z2V

14 CTS-V on top and 13 ATS on bottom. Only way I can get two cars in a less than two car garage with a beer box, tool box, knee mill, lathe, 7-1/2 hp/ 80 gal air comp.,water softener,  treadmill transformed into metal buffing/grinding table, lawn mower, etc, every square foot has purpose .
The tools are EASY to grind, get the angles right and just take it slow and easy. The suggested wood stick works well also. I used a piece of plywood I had close but I will dig around in my pile and find some oak when I have time.


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## mikey

*General Purpose Turning Tool*

I’ve already discussed what this tool does and pretty much how to grind it. With all we’ve discussed and my other articles, grinding a tool should be pretty old hat by now. In deference to Tweinke, I will just show how a left hand turning tool would be laid out. The grinding is the same – just grind to the lines. The rake angles would be the same but ground on the other side of the belt or wheel vs a RH tool. So, a mirror image of a RH tool.




Before I can explain why the Square Tool is ground the way it is, I have to briefly discuss cutting forces and how an angle table is used so that it makes sense.

*Cutting Forces*
There are actually three cutting forces in play whenever a tool comes in contact with a work piece. They are Tangential forces, Radial forces and Axial or Feed forces. I blatantly stole an image off the net because I’m too lazy to draw my own:




*
Tangential* forces (Fc in the pic) push down on your lathe tool when the tool is buried in the cut. They comprise about 75% of the sum of all the forces your tool experiences so anything that reduces or mitigates this force is a good thing.

*Radial* forces (Fr in the pic) push the tool out of the cut at a 90° angle. They are about 1/3 – ¼ the magnitude of Tangential forces but they matter because this is what causes deflection. Since the turning tool is somewhat rigidly mounted and is mostly non-compressible, Radial forces will cause the work piece to flex away from the tool instead. Our goal is to reduce this force to the extent we can to improve accuracy.

*Axial* forces are feed forces (Ft in the pic). In general, axial forces do not directly affect the cut. As the tool moves toward the chuck, the forces it encounters are these feed forces.

Each cutting force can actually be measured with strain gauges attached to the tool but I don’t own any. When I experimented with this stuff over 20 years ago, all I had was an ammeter hooked up to the motor of my lathe. My theory was that as I altered each angle of a turning tool, it would alter the cumulative cutting forces and I would be able to see a change in the motor load. I admit this is a really crude and insensitive set up but it was all I had at the time. Sadly, I lost the numerical data but I remember the results and here is what I think I know:

Cutting conditions matter. Assuming that motor load implies a change in cutting forces, as depth of cut and feed rate increase, cutting forces go up. As cutting speed increases, forces actually go down.
Increasing the relief angles reduces cutting forces. The more relief angles increase, the lower the forces. However, this also weakens the cutting edge so changes here must be conservative.
Increasing side rake reduces cutting forces more than increasing relief angles does. [It does this by shortening the Shear Plane length. The Shear Plane is an actual plane that extends at a 90° angle from the cutting tip through the thickness of the chip. As the Shear Plane length gets shorter, cutting forces go down, and vice versa.]
Increasing back rake reduces cutting forces (same Shear Plane nonsense) but less than increasing side rake does.
o  Back rake has more of an impact than you might think. If you look at the tool from the front you can see that the included angle at the side cutting edge is comprised of the side relief and the side rake angles. If you look at the tool from side you can see that the end relief and the back rake form another cutting edge, the end cutting edge. Alterations to either rake angle alters Shear Plane length so both impact on cutting forces.
o  Back rake also shifts the focus of cutting force concentration. In general, cutting forces will run perpendicular to the side cutting edge. This is reflected by the direction of chip flow. If you look at a tool ground with relief and side rake angles only, the chips will flow perpendicular to the side cutting edge. Now, when you add back rake you are adding that second included angle at the front end of the tool and that changes the focus of the forces. Now the chip flow direction is no longer perpendicular to the side cutting edge; it angles down and away from the tip of the tool. As back rake increases, the point where the chip leaves the work piece shifts closer and closer to the tip of the tool and when that happens the finish improves. Moreover, if you look carefully, you’ll see that chip flow rate actually increases and the chip thins out.
So, let’s summarize this into something useful:
1.   *Increasing the relief angles reduces cutting forces*. It also improves finishes because it reduces rubbing under the side cutting edge. Increasing relief angles removes support under the cutting edge; use restraint when the tool will see high cutting loads.

2.   *Increasing side rake reduces cutting forces more than increasing relief angles*. As side rake increases, chip flow accelerates. Since much of the heat in a cutting operation is retained in the chip, increasing side rake also reduces cutting temperatures.

3.   *Increasing back rake reduces cutting forces but less than changes in side rake does*. It accelerates chip flow so it also contributes to cutting temperature reduction. It also changes the focus of cutting force concentration and improves finishes.

4.   *As cutting speed increases, cutting force magnitude decreases*. This is useful, especially in harder materials. When you’re trying to come in on size, take a lighter depth of cut and increase speed and this will reduce Radial forces so there is less deflection. The tool cuts with greater ease and more accuracy.

You can use this information to modify any turning tool should you decide to do so. I’ll show you how to apply it shortly.

*The Angle Table*
In general, what defines the function of a lathe tool is its shape. How well it works and the material it works with is dependent on the angles the tool is ground with. If you look at a lathe tool angle table, you will see that the angles are material-specific.




The table angles define the tip geometry of a conventional lathe tool. You would choose a shape for your tool and then set your tool rest to grind the side and end (front) relief, then re-set the table for your side rake and angle the tool at your back rake angle and then grind both features at the same time. Each angle would change as you grind tools for each material type. The table is simple and easy to use.

When these tools are used on a larger lathe as they were intended, they work well. Unfortunately, when the same tool is used on a smaller, lighter, less rigid and less powerful lathe, they can produce cutting forces that may be excessive. If this is an issue for you then you might consider altering the geometry of your tools.

There is nothing sacred about these tables and there are no rules or laws that say you must grind your tools to these parameters. I don’t, and I don’t think you have to, either. However, the table is still useful because it gives us baseline values that we can modify to create a tip geometry that is more useful to us. We’ll get to this shortly but let me explain why the Square Tool is designed the way it is.

The design of the Square Tool is a compromise that allows it to work with multiple materials and with the lowest cutting force production I could manage. If you look at the angle table above, you will see that, on average, side relief is around 10-12°, end relief is 8-10° but the rake angles are all over the place. In order to reduce cutting forces, I increased the side and end relief angles to 15°; this is enough to lower forces but not enough to significantly reduce edge life. I settled on 15° of side rake because my tests showed that it resulted in a significant reduction in cutting forces but going beyond 20° seemed to increase edge wear more than I wanted, especially in medium carbon steels. I settled on 15° of back rake because this also reduced forces but more importantly, it shifted those forces just to the left of the tool tip. If you take a big cut with this tool, you’ll see the chip curling just to the left of the nose radius. This matters because this tool must be able to rough well but the tool also finishes pretty nicely. Placing the cutting force focus near the tip also allows the tool to face well because this is where a facing tool cuts.

Fooled you, eh? I bet you thought the 15° angle thing was just so I could give it a snazzy name like Square Tool – nope, not the case. It does work well with most common shop materials, so much so that I use it for most things except harder materials and stainless steel. This tool reduces cutting forces enough to enable my little Sherline lathe to at least double its depth of cut when compared to a conventionally ground tool so it does what it is designed to do. If you choose to reproduce it, I hope it works as well for you.
*
 Modifying Your Tools*
I’ve already written most of this stuff elsewhere but I’ll try to solidify it with a few examples. Say we want a general purpose turning tool for stainless steel. Whenever you need to cut something, you have to know the general machining properties of that something because this influences your tool angles. There are many formulations of stainless steel and I’ve only worked with 303, 304, 316L and 416. None of these is especially hard as supplied but they do work harden readily; dwell in a cut for too long and it gets hard enough to make you wish you were using a carbide tool.

Let’s decide that we’ll use our general purpose shape and that we want to accomplish two major things with our angles. First, we want to reduce cutting forces so that the tool cuts more freely, and secondly we want to prioritize cutting temperature reduction. Both goals are aimed at minimizing work hardening so we can come in on size. Having a nice finish would be nice as well.

The standard relief angle for SS is 10° but 12-13° would reduce cutting forces without affecting edge life too much. Standard side rake is 15-20° but I would take it up to 25° to reduce cutting forces, improve chip evacuation and keep cutting temps low. Standard back rake is 8° and here we need to make a choice. If we leave back rake at baseline then the tool will focus the cut at the side cutting edge. If we increase it, the tool will cut more freely and may finish better but may not be able to rough as well. In cases where I need to push the tool fairly hard, I try not to boost back rake too much so I would opt to increase back rake only a few degrees – maybe 10° max. You might think this won’t do anything but remember that the effect of these angle changes is cumulative; it will make a difference.

I would also keep the nose radius on the smaller side – 1/64” or so. The reason is to minimize radial forces. Why is it important for this tool? Because high radial forces will increase deflection and when the tool deflects it doesn’t cut and when it doesn’t cut, it builds heat.

You should know that the nose radius on any cutting tool has a big influence on radial forces; the larger the radius, the larger the radial forces. In general, radial forces will increase until the depth of cut exceeds the nose radius. Once the nose is buried in the cut where it is fully supported then radial forces tend to stabilize. It follows that the smaller the nose radius, the sooner it gets buried and supported so try to keep your nose radii on the smaller side when cutting hard stuff or stuff that work hardens.

This is getting to be a long post but let’s quickly look at a general purpose tool for aluminum. The Square Tool will work but not as well as a tool optimized for the material.

We can see that standard relief angles are 12 and 8 for the side and end. Since aluminum is fairly soft, we can easily increase both to 15° without endangering the edges. Side rake is already at 18°, which is a pretty healthy amount so I would leave it as is and boost back rake. Standard back rake is already huge at 35° but by increasing it to 40° we do several things: we reduce cutting forces, we focus all the cutting at the very tip of the tool to enhance finishes and we greatly accelerate chip flow to reduce cutting temperatures (because aluminum gets gummy when it heats up). Nose radius can be a bit larger, no more than 1/32”, and it will finish very well.

I have a tool ground exactly like this, with the same reasoning, and it will easily take a 0.25” deep cut on my 11” lathe. I know for sure it will go a lot deeper but I haven’t needed to waste material or prove the tool; it works for me. It has never developed a built up edge if I use WD-40 to lube the cut and the chips flow right off the tip as you would expect. It produces a near mirror finish when roughing and a mirror finish when finishing. It cuts with very little radial deflection so what you dial in is usually what you get. If you must take a lot off the diameter of a work piece, dial in a heavy cut and increase feed. This tool will create chips, not stringers, under those conditions and the tool will cut with minimal effort. You might give this one a try.

Okay, so that is the “how” of tool mods. Learn about your material then choose which angles to change to accommodate it. How much to change an angle is a guess but I try to keep them conservative, about 25-40% more than the baseline angle. In most cases, this only amounts to between 2-5° per angle but the changes are cumulative and a little bit can go a long way. You need to try this process to get a feel for it.

How do you tell if your geometry changes actually do something? What I do is grind a tool to the standard angles and see how it works. Then I grind a second tool to standard angles and then I modify one angle and assess. Then I change another angle and reassess. I keep this up until I’ve modified all the angles I want and then I focus on optimizing the amount of angle change. Maybe a degree more side rake will help, or a bit more back rake may improve the finish. The only way to know is to try it and see. When I have the tool cutting exactly the way I want it, I grind a keeper from a blank I trust.

This is already incredibly long and I’m repeating what I’ve said elsewhere but of all the tools you will grind, your general purpose tools will be the most useful. Now you know how to grind it, how to modify it, how much to change it and how to assess it.

You can take it from here.


*








*


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## Fallriverbryan

One of my concern is where our relief angles meet. Actually, I have started using Fusion 360 so hopefully I will be able to include a diagram to illustrate my point but I will try and explain. I work with stainless, I grind to hold the edge, I don't grind my side rake all the way to the cutting edge. I leave 1/32 inch of 0 degree side rake angle. Is that the proper way or is that a mistake?

Sent from my SM-G950U using Tapatalk


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## T Bredehoft

Z2V said:


> I just went in the garage and made a tool based off what Mike has already posted and I can say this tool cuts better than anything I have used on my little Craftsman lathe. I was able to make deeper cuts than before and with a much better finish. And this was my first try at doing it Mikes way!! I might try his knife tool latter this evening also.
> Thanks Mike!!



Jeff, and Mike, I had exactly the same experience. I worked as a  tool & die maker for 29 years, always used carbide tooling. Mike's explanations are the first real inkling I had as to tool geometry. 
Thanks, Mike for the lessons, thank's Jeff for sharing your experience with us.


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## mikey

Fallriverbryan said:


> One of my concern is where our relief angles meet. Actually, I have started using Fusion 360 so hopefully I will be able to include a diagram to illustrate my point but I will try and explain. I work with stainless, I grind to hold the edge, I don't grind my side rake all the way to the cutting edge. I leave 1/32 inch of 0 degree side rake angle. Is that the proper way or is that a mistake?
> 
> Sent from my SM-G950U using Tapatalk



As you know, the thing with stainless is that it hardens with heat. It likes slightly larger relief angles so it doesn't rub and build heat. Side rake channels the chips out of the cut and the more side rake you have, the faster the chips leave. Since most of the heat in a cutting operation is carried out by the chip, you want the side rake angle to be as efficient as possible. Leaving a land between the cutting edge and side rake angle will reduce the cutting action of the tool, slow the chip flow and you'll build heat faster and the part will harden.

My suggestion is to increase relief by a few degrees, boost side rake a few more degrees and make them meet at the edge. It has been shown that tool life increases as side rake increases so boost side rake and create a sharp cutting edge.


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## mikey

T Bredehoft said:


> Jeff, and Mike, I had exactly the same experience. I worked as a  tool & die maker for 29 years, always used carbide tooling. Mike's explanations are the first real inkling I had as to tool geometry.
> Thanks, Mike for the lessons, thank's Jeff for sharing your experience with us.



Thank you for your kind words, Tom. It's exciting to me that you guys are taking mere words and pictures and turning them into tools that help you in your work. It will be interesting when you start to design your own tools so they work the way you need them to. When that happens then you know you have it.


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## Fallriverbryan

mikey said:


> As you know, the thing with stainless is that it hardens with heat. It likes slightly larger relief angles so it doesn't rub and build heat. Side rake channels the chips out of the cut and the more side rake you have, the faster the chips leave. Since most of the heat in a cutting operation is carried out by the chip, you want the side rake angle to be as efficient as possible. Leaving a land between the cutting edge and side rake angle will reduce the cutting action of the tool, slow the chip flow and you'll build heat faster and the part will harden.
> 
> My suggestion is to increase relief by a few degrees, boost side rake a few more degrees and make them meet at the edge. It has been shown that tool life increases as side rake increases so boost side rake and create a sharp cutting edge.


Thanks. I think it works for me at work with heavy cut and flood coolant. Definitely will try these adjustments on my Atlas in the garage.

Sent from my SM-G950U using Tapatalk


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## mikey

*The Knife Tool*

The knife tool is a simple facing tool and it does that job extremely well. I made one many years ago and thought I invented something but then I read an article by Ian Kirby of the UK and discovered that it had been in use for some time … nothing new under the sun, I guess.

It turns out that our British cousins use the knife tool for a lot more than just facing; they turn and finish with it, too. You need a larger nose radius to turn with this tool. To finish, a small (1/32”) flat across the nose will create a nice finish. I tried knife tools configured this way but I prefer the Square Tool myself. Try it and see how you like it.

The knife tool is really stiff but also has a rather delicate tip that allows it to get into a tight corner and face out. The tip also allows you to chamfer inside or outside corners and grooves. But what the knife tool excels at is facing. It has a long, sharp edge that allows you to skim cut a face and leave a beautiful finish, better than any other tool I’ve seen. All you need to do is get the cutting edge just off parallel with the work, come into contact and face out.

When I need the work piece to have a shoulder that is a precise distance from the end of the work, this is the tool I use to face the shoulder to give me that distance. It will take a 0.0002” depth of cut and actually cut it. Most facing jobs are not precise but when you need precision, this tool will work for you.

The geometry of this tool is really simple. It has a 15° side and end relief angle; this greatly reduces rubbing and allows the tool to cut with very low cutting forces. It has 15° of side rake to enhance chip clearance; I chose this so it would work well with most materials, including Stainless Steel, and it does. Back rake is only 10° because I wanted the cutting forces focused at the side cutting edge, up close to the tip. If you take a light turning cut with this tool, you will see the chip come off near the tip of the tool as intended.

The nose radius on my personal tool is really small; I can see it but only if I look hard. I wanted a small nose radius so I could cut a corner with the smallest radius I could manage and it works well for that. Another reason for a small nose radius is to reduce radial cutting forces so that I can take really tiny sizing cuts on a thin work piece. As we all know, thin work pieces tend to deflect due to radial forces and a small nose radius really helps to reduce those forces. With this tool, I can take cuts small enough that the chips float away when the wind from my fan hits them. Your tool must be very sharp to do this but when I have to size a really small work piece, the knife tool is what I use.

My knife tools are made from cobalt HSS because it retains an edge longer. The one described above is for most stuff and I have another one for harder stuff; that one has 13° of side and end relief and 18° of side rake and 10° of back rake. The difference is to allow it to cut harder stuff and clear the chips faster to reduce work hardening. It doesn’t get used often.

Take the time to hone this tool well initially, then do this after every use and it will be ready when you need it. My tool will slice curlicues in newsprint.

There isn’t much more to say about this tool. You can also make a traditional facing tool. If you look closely at the traditional shape it is almost exactly like a knife tool without the bulk. The knife tool is much easier to grind so try one and see how you like it.


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## mikey

*60° Threading Tool*

My personal threading tools, a 3/8" Super-Mo-Max tool for larger threads on the left, a Rex AAA tool for smaller threads on the right.




This is just a standard threading tool, ground to an accurate 60° included angle at the tip. As noted, the tip is moved over to the left of the blank to allow you to get closer to a shoulder or thread relief before the shank of the tool hits it. You can grind it even closer by making the left side angle smaller.

This tool has 15° relief angles. It isn’t that I have a love affair with 15°; I actually ground tools with different relief angles to find one that cut clean threads without leaving all sorts of burrs or defects in the threads; 15° just happened to be the best of the lot, that’s all. This is a zero-rake form tool (just a fancy way of saying the top is flat) so it cuts with higher cutting forces but since we cut threads at low speed, it isn’t a hindrance. I grind a 1/64” flat at the tip; this is to keep the tip from cracking right off, which it will do if you don’t include it. This also forms a flat at the bottom of the thread, which is desirable.

When you grind this tool, grind it precisely and hone it just as precisely. Don’t forget to hone the top, too. You will be amazed at how much better your threads will look when the tool is razor-sharp.

If you only cut threads with the compound and do not feed straight in with the cross slide then you can grind 5° of side rake into the tool and it will cut easier, clear chips better and will be just as accurate.

Not much more to say about this simple but essential tool.


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## Rockytime

mikey said:


> You can see my grinder and tool rest here: http://www.machinistblog.com/modifying-a-craftsman-2-x-42-inch-belt-sander-for-tool-grinding/#more-5349.
> 
> Hi Mikey, FYI I just purchased the Craftsman 6" disk and 1x72 belt 1/2 hp sander. I think I paid a little more than I should have on fleabay but it is certainly sturdy and runs well. Only modification will be a new table. I grind nothing over 1/4" and quire a bit smaller. Wood gouges sharpen on a 4" sander. Now for new belts. Thanks for showing your mods.
> 
> Regards, Les


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## mikey

Awesome, Les! The 1/2hp models are rare, even the 1" belt models. I hope it works as well for you as mine does for me. Keep us posted!


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## mikey

*Model Tools – End Notes*

Guys, I’ve given you just about everything I know about tool grinding. I’m sure I didn’t catch it all so if I missed something, please tell me so I can fix it. Some of what is in this thread may differ from what I’ve written in the past; this is because like you, I am still learning and still trying to improve. What I posted in this thread is my current practice, for whatever that is worth.

I want to briefly mention the various kinds of tool blanks available. I’m including this because when I started, I had no idea what was what, which was better for a given application or if cheap Chinese stuff was okay.

My personal practice is to use 3/8” blanks for everything. Keep in mind that I only have a Sherline and an Emco 11” lathe. I would use 3/8” tools up to a 13” lathe, then step up to ½” tooling on larger lathes. This has less to do with stiffness; these tools are damned stiff. It has to do with grinding times. ½” tools take me twice as long to grind and they aren’t any better performance wise; call me lazy.

For a budding tool grinder, I believe the first and best steel to learn with is mild steel *keystock* from the hardware store that is cut to the length of a tool bit. It is going to take a while for your brain and hands to coordinate their efforts to produce a lathe tool shape that actually looks like a lathe tool. My advice is to stay with keystock until you are totally comfortable that you can grind the shape and angles you want without any problems, then move on to M2 HSS. HSS requires more pressure to grind, and cobalt or tungsten steels will be even harder so don’t be in a rush. Grinding keystock will pay dividends, believe me. Okay, let’s move on to HSS.

I think of HSS as M2 or cobalt. M2 is your basic HSS without cobalt in the alloy. It is the cheapest tool steel, easiest to find and to grind and is the most impact resistant of the tool steels. M2 will handle almost all the common materials we use in the hobby shop – mild and medium carbon steels, aluminum, brass, plastics or wood. It is fairly abrasion-resistant and holds a keen edge. This should be your daily driver unless you're working with hard stuff.

When working with higher carbon steels, semi-hardened steels, stainless steels and other more unusual materials (Titanium), cobalt or tungsten HSS may be a better choice. I say “may” because most of these harder turning materials are usually machined with deep cuts at higher speeds and feeds. While these alloyed steel tool bits retain their hardness and edges at the higher temperatures these cutting conditions impose, whether your small hobby lathe has the power or rigidity to make the cuts required is another thing. Moreover, the higher temperatures that result from machining these materials can, and often does, result in work hardening and this can make taking accurate sizing or finishing cuts a challenge. This is why inserted carbide tooling is usually chosen when working with harder materials. So, why not just use carbide tooling for these materials? You can, if you have the speed and rigidity those tools require.

This is where being able to grind a custom tool comes into play. If you run a small lathe, the cutting forces and cutting temperatures will be quite high when machining harder materials if you use standard tip geometry, but if you were to grind a tool that reduces those forces and temperatures then your lathe will often perform much better. So, when we think of working with harder materials we do need to think about which tool material to use but we must also attend to the tip geometry of that tool; the smaller the lathe, the more important this becomes. Moving on …

In the non-M2 class, we have the Tungsten steels (the T-series of HSS) and the Molybdenum steels (the M-series HSS). Note that beyond the M2 steels, cobalt is added to the M-series alloys to provide its heat and abrasion resistant properties, while Tungsten is the key alloying material in Tungsten bits (they also have cobalt in them). There are actually 7 tungsten steels and 17 molybdenum/cobalt steels but most of them are specialty steels that you won’t see in the form of a square lathe tool bit. Between the two, the M-series is far more available.

*Tungsten*

The common grades you will see will be T4, T8 and T15 but rather than the alloy, they are usually labelled with some catchy name. Crucible was the main supplier of Tungsten HSS:

·      Rex AAA = T4

·      Rex 95 = T8

·      CPM Rex T15 = T15

·      Teledyne used to make the Vasco Supreme = T15; this is an outstanding tool bit if you can find them.

·      I’m sure there are others that I don’t know about.

*Molybdenum and Cobalt*

·      Cleveland Mo-max = M2. This is the highest quality M2 tool bit I know of. Most are made in Mexico now but older stock was made in the US and can still be found on eBay. The country of origin is printed on these bits and both work well.

·      ETM HSS – M2 of consistent high quality. One of my favorites.

·      Armstrong, Morse, Chicago-Latrobe are all good M2 HSS.

·      Cleveland Mo-max cobalt = M35 cobalt or 5% cobalt

·      Cleveland Super-Mo-Max = M42 cobalt or 8% cobalt

Some generic bits will be labelled “HSS-Co”. I do not know the content of these bits but they contain cobalt; could be 5%, 8%, whatever. I have used all those mentioned above and all are high quality. If I had to choose only one, I would choose the USA-made Mo-max M2 HSS for its consistent quality. For cobalt bits, I prefer the Super-Mo-Max bits but also like the tungsten-bearing Vasco Supreme and anything from Crucible.

So, what about tool bits from China, India, Poland, Japan or Israel? I have used some very high quality bits from Japan and Israel (TTC, the house brand from Travers) and they work great. Chinese bits vary in quality and most of them are not labelled; this makes it difficult to assess them. However, if I was a budding tool modifying monster, I would use Chinese import bits until I hit on a winner design, then make it from a known high quality blank.

*Honing*

I suggest using diamond stones to hone your tools with. I prefer the mono-crystalline stones from DMT but the poly-crystalline stones from EZ-Lap are okay. For most honing, I use the credit card sized stones in coarse, fine and extra-fine grits. You can use water as a lubricant. I recently discovered the wetting agent from Accu-finish and it works really well and stays on the stone longer.

I hone my tools after every use and oil them before storing. Sharp is good for turning tools and its nice when I pull a tool out and know that is honed and ready to go. Treated this way, a good HSS tool will last for well over a decade.

Let me end this by saying that a well-ground HSS tool is a joy to use. However, it is not the only tool to use. There are times when a brazed or inserted carbide tool will be better and you need to find out when that is. I would encourage you to grind conventional tools and then compare it to your carbide tooling and your modified HSS tools to see which are better for your needs. Keep an open mind about tooling; all are useful but only one will be the best for the job at hand – use that one.

Thanks for following along. I hope the model tools and the information in this thread is useful to you. Please post to this thread about your models or your own tools and experiences. I, for one, would like to see them. Again, if I missed anything or glossed over something that needs clarification, please let me know.

EDIT: I forgot to mention that when stoning on your nose radius, be sure you maintain the angle of the tool at the front. Stone a flat from top to bottom, then carefully round and  blend it into the side and end faces. For your threading tools, you only need a flat; you do not need to round it. When deciding on nose radii, it is better to go small unless you need a better surface finish; don't forget that the bigger the nose radius, the higher the radial forces and deflection will be. By small, I mean 1/64" to 1/32". Look at a radius gauge in these sizes to get an idea of what you need and then just estimate it as you stone it on. You do not need to be precise in this but try to get close.

Mike


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## tweinke

I just thought of one more tool that may be of interest to others and my self. how about a tool for a fly cutter? While not necessarily a lathe bit it could be useful information in the hobby shop if you have any insights on one. Seems about all the info I find is just a hint to grind as a left turning tool, how about how to make it better? This whole thread has been awesome and hopefully will be made into a sticky on here somewhere.


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## mikey

I don't know what the other guys think but I can give you my take on a flycutter tool. I used to grind a left hand roughing shape with a fairly generous nose radius - slightly larger than 1/32". I wasn't too deep into tool modifying back then but I wasn't too thrilled about tool life, although the finish was really good. When doing harder materials, I could go through three tool bits just squaring a work piece made of stainless steel. Then I discovered Sherline's inserted carbide flycutter that had a much longer work life and never looked back.

Knowing what I know now, here is what I would try if I were to grind a flycutter bit:

Almost every cut will be an interrupted cut so I would only use M2 HSS; cheaper, more impact-resistant, fast to grind. 

For a shape, I would grind a roughing tool shape or possibly a general purpose shape like our square tool. Depending on depth of cut, cutting loads may be very high.

Flycutters run at high speed, which lowers cutting forces so we can afford to keep relief angles near baseline levels for strength. 

Since the relief angles are stronger, we could afford to increase side rake to boost chip clearance and lower forces more so I would go maybe 4 degrees above baseline. 

Almost all cutting is at the tip so I would boost back rake by 5 degrees and this will put all the cutting action at the tip. 

Then I would grind a nose radius just a tad bigger than 1/32".
I'm pretty convinced that a LH Square tool would work pretty good if you gave it a slightly larger nose radius. The only way to know is to try it. Of course, you would change the side cutting edge angle of the tool to be sure the nose was the contact point but that's pretty simple to do.

Dunno' ... what do you think? Why not make a LH square tool and try it, then report back and we can brainstorm on it.


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## tweinke

Next time I'm in the shop with a fly cutting tool job I will definitely give that a try!


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## IanT

Hi Mikey,

A very interesting set of posts but I do have a question about 'relief' angles (I tend to call them clearance). My understanding has always been that the relief angles are exactly that - they provide sufficient 'clearance' to stop the tool rubbing on the work. I also understand that if the relief angle is increased the 'lip' angle is decreased and the cutting edge thereby weakened. But I'm not sure how changing the relief angle improves the 'sharpness' of the tool - that to my mind is a matter of the amount of rake applied (be that side and/or back).

I routinely use the wheel periphery to give clearance to my tools - and the slight curve imparted also helps when stoning the top edge. I do vary the rake(s) used, dependant on material to be cut but not the clearances. I have a mental picture of how this all works but cannot quite see how more relief makes for better cutting? Surely there is either sufficient clearance  or there is not?

Regards,

IanT


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## mikey

IanT said:


> Hi Mikey,
> 
> A very interesting set of posts but I do have a question about 'relief' angles (I tend to call them clearance). My understanding has always been that the relief angles are exactly that - they provide sufficient 'clearance' to stop the tool rubbing on the work. I also understand that if the relief angle is increased the 'lip' angle is decreased and the cutting edge thereby weakened. But I'm not sure how changing the relief angle improves the 'sharpness' of the tool - that to my mind is a matter of the amount of rake applied (be that side and/or back).
> 
> I routinely use the wheel periphery to give clearance to my tools - and the slight curve imparted also helps when stoning the top edge. I do vary the rake(s) used, dependant on material to be cut but not the clearances. I have a mental picture of how this all works but cannot quite see how more relief makes for better cutting? Surely there is either sufficient clearance  or there is not?
> 
> Regards,
> 
> IanT



The side cutting edge is an intersection between two planes, the relief angle and the side rake angle. This forms an included angle defined by those two planes, right? You can reduce the included angle by increasing either the rake or relief angles and the result would be the same; I assume this is what you mean by "sharpness". The downside to increasing the relief angles is that you lose some support under the cutting edge so tool life tends to go down but a little bit goes a long way.

But here's the thing. I used to think that once you have clearance then you have it. That was until I measured motor load and varied the relief angles and found a reduction in motor load as the relief angles increased. This can be due to a reduction in cutting forces (can't tell without a strain gauge) or that there is more rubbing than the published angles would lead us to believe or both. Regardless of which it is, a small increase in relief angle does reduce motor load and, by inference, cutting forces. 

Hope that helps.


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## mikey

Wanted to post a follow up on the ceramic belts that ate my keystock. They are _*excellent*_ for grinding HSS and cobalt HSS. I used a 35 grit ceramic belt that shaped a tool about twice as fast as an Aluminum Oxide 24 grit belt. It also cuts much cooler. Normally, an AO belt turns the HSS a straw color due to the heat but the ceramic belt cut it faster and with no color change to the steel. The ceramic is a finer grit so I expected it to grind with finer grind marks but it is much finer than I thought it would be.

The 80 grit ceramic belt cuts much faster than its AO counterpart but cooler and faster, too.

Bottom line - I found a new kind of belt. Bye bye, AO! Amazon carries them for a good price.


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## Fallriverbryan

mikey said:


> Wanted to post a follow up on the ceramic belts that ate my keystock. They are _*excellent*_ for grinding HSS and cobalt HSS. I used a 35 grit ceramic belt that shaped a tool about twice as fast as an Aluminum Oxide 24 grit belt. It also cuts much cooler. Normally, an AO belt turns the HSS a straw color due to the heat but the ceramic belt cut it faster and with no color change to the steel. The ceramic is a finer grit so I expected it to grind with finer grind marks but it is much finer than I thought it would be.
> 
> The 80 grit ceramic belt cuts much faster than its AO counterpart but cooler and faster, too.
> 
> Bottom line - I found a new kind of belt. Bye bye, AO! Amazon carries them for a good price.


Hey Mikey
I have a medium coarse diamond wheel for sharpening carbide. Have you even used one to sharpen HSS? I've heard it is not advisable but I have done it while applying coolant during the sharpening process.

Sent from my SM-G950U using Tapatalk


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## mikey

Fallriverbryan said:


> Hey Mikey
> I have a medium coarse diamond wheel for sharpening carbide. Have you even used one to sharpen HSS? I've heard it is not advisable but I have done it while applying coolant during the sharpening process.
> 
> Sent from my SM-G950U using Tapatalk



No, I don't have any experience with that kind of wheel. I do have an Accu-finish that turns at 300 rpm and at that speed, finish grinding HSS is no problem. Using diamonds for steel is only an issue at high speeds; my limited understanding is that the heat can weaken the bonding agent that holds the diamonds on. I guess using coolant like you're doing would keep the heat down nicely, Bryan, so I'm not surprised it works.


----------



## mikey

I forgot to mention that these ceramic belts seem to last longer than the AO belts. I ground 9 model tools, a HSS tool and two Rex AAA (5% cobalt) and the belt seems to be as sharp after all of that as it was in the beginning. It took me just a few seconds longer to grind each face of a cobalt tool than it did to grind them on mild steel keystock. 

I am really impressed with these belts!


----------



## ttabbal

Metal said:


> 3dp examples came out good, they aren't 100% accurate but the labels turned out readable and give a good idea of what the finished product should look like
> 
> well they would be at least if I didnt print them in black, hah.




That's great! I have a 3D printer and would be willing to print some up for group members when the models are ready. 

Been on vacation and catching up with the thread. Great stuff mikey! Thanks! Now I need to come up with something to grind them with.


----------



## DHarris

OK all, I just received Mikey's model tool in the mail (Monday @ 12:00 noon Calif. time).  Started to run right out to the garage when wife grabbed me by the ear and said "eat lunch first because I know I won't see you till after dinner time".  So, dutifully obeying - I choked down lunch and THEN ran out to the garage!

Note - I'm a complete newbie on lathe tool grinding! 

First thing I did was to cut and pasted all of Mikey's write-ups into one single MS Word document (all 23 pages of write ups!  Hell of a task and job well done by Mikey, I might add!).  Printed it out and into the garage I went.  Started with the basic RH cutting tool.  Followed the instructions step - by - step and compared my tool to the Sample Tool.  It was amazing, even on my old rickety belt sander it took less than 20 minutes to grind.  And, this is with me going from 36 grit, to polish with 80, and then just for S%its & Giggle's 220 grit.  finished off with honing it.  IT CAME OUT GREAT!!!!! and the bloody thing is SHARP!

 Apparently, for me at least, what has been missing was a simple step - by - step walk thru to make it clear and easy to do!

Other things i discovered while grinding the 3 sample tools - - 
1) the platen on my belt grinder is not rigid enough.
2) Belt grinder motor is a wimp - it's 30 years old & from harbor freight
3) Table is definitely not rigid enough - flexes down from left to right under pressure (is
      only held on left side by one bolt.
4) No easy, accurate & repeatable way to place angles on table

So, basically, belt sander is crap - - good for general roughing & / or wood sanding in garage.  OH BOY, VALID EXCUSE TO BUY A NEW TOOL!!

Attached is a photo of the tool model (bright shiny tool on right) and my grind (dull color on left).  Note: I had not put the slight rounding of the nose on my tool when this photo was taken.




A final note - - after grinding the 3 samples tools in key stock - I duplicated this RH tool in a cheap Chicom metal HSS tool blank I had laying around.  Put it in the tool holder in my Sherline lathe & started making cuts I never would have thought possible on this small lathe.

THANK YOU MIKEY FOR TAKING THE TIME & PUTTING IN THE EFFORT TO HELP US NEWBIE'S LEARN & GROW IN THIS HOBBY!   (and yes, I did blame you for needing the new belt sander when I told the wife!)

Dave Harris

ps,  It's now 2:30 Calif. time & I'm prepping the 3 sample tools to send up to Canada tomorrow!  So, in roughly 2 hours I cut the 3 sample tools, one HSS tool and made some cuts!


----------



## Z2V

You didn't waste any time jumping right in. Looks good!


----------



## Ken from ontario

DHarris said:


> Other things i discovered while grinding the 3 sample tools - -
> 1) the platen on my belt grinder is not rigid enough.
> 2) Belt grinder motor is a wimp - it's 30 years old & from harbor freight
> 3) Table is definitely not rigid enough - flexes down from left to right under pressure (is
> only held on left side by one bolt.
> 4) No easy, accurate & repeatable way to place angles on table
> 
> So, basically, belt sander is crap - - good for general roughing & / or wood sanding in garage. OH BOY, VALID EXCUSE TO BUY A NEW TOOL!!




I'm also convinced you need a new grinder.


----------



## tweinke

Received the models today at noon in the mail, looked at them ate lunch, then had to go back to work.   Will have time to try tomorrow to grind my own unless the wife goes to bed early then tonight is the night! Thoughts of sleeping pills come to mind though, not for me but someone else.   Cant wait to try but I really need to finish the rush project I started yesterday for a coworker or maybe not,


----------



## mikey

DHarris said:


> OK all, I just received Mikey's model tool in the mail (Monday @ 12:00 noon Calif. time).  Started to run right out to the garage when wife grabbed me by the ear and said "eat lunch first because I know I won't see you till after dinner time".  So, dutifully obeying - I choked down lunch and THEN ran out to the garage!
> 
> Note - I'm a complete newbie on lathe tool grinding!
> 
> First thing I did was to cut and pasted all of Mikey's write-ups into one single MS Word document (all 23 pages of write ups!  Hell of a task and job well done by Mikey, I might add!).  Printed it out and into the garage I went.  Started with the basic RH cutting tool.  Followed the instructions step - by - step and compared my tool to the Sample Tool.  It was amazing, even on my old rickety belt sander it took less than 20 minutes to grind.  And, this is with me going from 36 grit, to polish with 80, and then just for S%its & Giggle's 220 grit.  finished off with honing it.  IT CAME OUT GREAT!!!!! and the bloody thing is SHARP!
> 
> Apparently, for me at least, what has been missing was a simple step - by - step walk thru to make it clear and easy to do!
> 
> Other things i discovered while grinding the 3 sample tools - -
> 1) the platen on my belt grinder is not rigid enough.
> 2) Belt grinder motor is a wimp - it's 30 years old & from harbor freight
> 3) Table is definitely not rigid enough - flexes down from left to right under pressure (is
> only held on left side by one bolt.
> 4) No easy, accurate & repeatable way to place angles on table
> 
> So, basically, belt sander is crap - - good for general roughing & / or wood sanding in garage.  OH BOY, VALID EXCUSE TO BUY A NEW TOOL!!
> 
> Attached is a photo of the tool model (bright shiny tool on right) and my grind (dull color on left).  Note: I had not put the slight rounding of the nose on my tool when this photo was taken.
> 
> View attachment 242582
> 
> 
> A final note - - after grinding the 3 samples tools in key stock - I duplicated this RH tool in a cheap Chicom metal HSS tool blank I had laying around.  Put it in the tool holder in my Sherline lathe & started making cuts I never would have thought possible on this small lathe.
> 
> THANK YOU MIKEY FOR TAKING THE TIME & PUTTING IN THE EFFORT TO HELP US NEWBIE'S LEARN & GROW IN THIS HOBBY!   (and yes, I did blame you for needing the new belt sander when I told the wife!)
> 
> Dave Harris
> 
> ps,  It's now 2:30 Calif. time & I'm prepping the 3 sample tools to send up to Canada tomorrow!  So, in roughly 2 hours I cut the 3 sample tools, one HSS tool and made some cuts!



Glad you got the models done without too much trouble, Dave. Your tool came out really nice so obviously something is clicking for you guys here. Is it the model or the description or both? In the past, I've tried to make it simple but failed so something we're doing is different. Anyway, congratulations, Sir!

23 pages? Not from this thread, right? Actually, it takes a lot of words to convey understanding. Would that I could just talk to you guys and show you first hand but that isn't going to happen so this is the next best thing.

Anyway, now you know how easy it is to grind a tool. Now you need to try making some material-specific tools and then you'll be on your way. 

Good for you, Dave. Now we have you, Jeff and Tom grinding better tools. That's a win in my book.


----------



## tweinke

Ground all three models in keystock because all I have on hand is Stellite or mo-max bits. Belt grinder needs new belts after the last project and of course no one in town carries 1x42 belts. now I have samples so that's a good thing. I have ground Mikey's bits from a posting he had elsewhere but the models helped me understand better. The models are off to the next recipient as of about 30 minutes ago.  Thanks Mikey!!!!


----------



## ddickey

I could've just drove over and picked them up.


----------



## tweinke

Wish we could have done that. To top it off I will be in Rochester this weekend for a wedding.


----------



## Z2V

Sorry guys, I missed that you were that close together.


----------



## mikey

tweinke said:


> ... the models helped me understand better.



Then they were worth making. Thanks, Todd.


----------



## Doubleeboy

I got the models from Mike a few days ago, they were as expected, my young friend who is starting out will get a copy that I make for him.  Been grinding tools a long time, but seeing Mike's first hand was helpful.  Anyone who wants to learn how to grind HSS would be well advised to take part in this generous offer to have the tools for a few days for the cost of shipping.

michael


----------



## mikey

Doubleeboy said:


> I got the models from Mike a few days ago, they were as expected, my young friend who is starting out will get a copy that I make for him.  Been grinding tools a long time, but seeing Mike's first hand was helpful.  Anyone who wants to learn how to grind HSS would be well advised to take part in this generous offer to have the tools for a few days for the cost of shipping.
> 
> michael



Thanks, Mike. With your guidance, he'll be an Ace in no time!


----------



## tweinke

Z2V said:


> Sorry guys, I missed that you were that close together.



I'm sure you have your hands full just handling the logistics of this fine endeavor!


----------



## mikey

Bonehead just left my house - came over for a visit, which means his wife allowed him to go out in public; this is a rare thing because he is ugly enough to frighten women and small children. He doesn't own a computer and only has a dumb phone so if he wants to see something on the net, he comes here. Anyway, he actually read this entire thread after I showed him how to scroll with the mouse wheel and he said that while I mentioned the push block a few times, he felt it is important enough to make an issue of it. 

Bonehead doesn't just use the block to apply force into the belt. He steers the tool with it and he feels it is a key to grinding accurately, especially if you're a newbie and are grinding to a line. He is adamant that only plywood will do; something about the different layers grabbing the edge of the bit better.

His physical repulsiveness aside, Bonehead is probably one of the most intelligent men I know. He only has a high school education but he is an amazing engineer, the best I've ever seen. He grinds tool bits that are works of art and hones them to a mirror finish so despite the fact that he is coarser than a 24 grit belt in his speech, he does know what he's talking about. You might want to listen to him.

His parting shots to me: " You're too wordy and repetitious, and you write like a girl. "

Le Sigh ...


----------



## Aukai

LOL


----------



## ddickey

Get Bonehead on the forum.


----------



## mikey

ddickey said:


> Get Bonehead on the forum.



I tried, I honestly did. I even offered to buy him a laptop. I swear, he just looked at me like I smelled bad and said, "NO!". When Bonehead says no, nothing on this earth will change his mind. I even appealed to his wife and she literally looked alarmed. She said, "Why would you want to do that? He pisses people off just being alive!" They must have a really interesting and colorful marriage.

Bonehead once made a 3D archery target. It was a moving platform with a foam Javelina archery target mounted on it. He used a wireless remote control and could make the target turn on a dime instantly and run at realistic pig speeds. He made the whole thing (except for the electronics) with a hacksaw, files and a few screws. And this was 20 years ago. When every archer on the field complained that he cheated and turned the target just as they were ready to shoot, he said, "It's not my fault that you guys suck; get better instead of complaining."

Now you begin to understand his wife's sentiments ...


----------



## tennsmith

I think it is a great idea and would be interested in getting on whatever mailing list that is formed to distribute the patterns.


----------



## mikey

Please send a PM to @Z2V and he'll put you on the list.


----------



## bigbull

Thank You For Sharing mikey
bb


----------



## Z2V

tennsmith
I'll be glad to add you to the list, all I need is an address in a PM

Jeff


----------



## Randall Marx

Bonehead sounds very much like me! Except for the being great at grinding lathe tool bits.


----------



## mikey

Randall Marx said:


> Bonehead sounds very much like me! Except for the being great at grinding lathe tool bits.



I know it looks like I'm making stuff up about Bonehead but I'm being quite honest. He really exists, everything I quote is real (including his wife's statements) and he really is unfortunate-looking. A more obstinate curmudgeon is unlikely to exist but he is also the most brilliant natural engineer I have ever seen. He has been my friend, hunting and fishing partner and collaborator for almost 40 years and I know no other human who lacks as many social skills. He keeps life interesting, that's for sure.

From what I have seen, Randall, you aren't even close to being like Bonehead - you're too normal!


----------



## tweinke

So just wondering, how are you guys doing with the models? For me the models and Mikey's write up together made all this angle stuff add up in my head. I had read about two years ago his write up on a different site one night and attempted his way of grinding tools and did have some success because I did end up with tools that worked, as a mater of fact I reground those tools with the models in hand and I think they work better now. I will keep those as standards and still use them but if I need or want to grind different angles I will grind new tools. A big thank you to Mikey and Jeff for there efforts to teach us because I do understand the time and effort to make this happen.


----------



## ddickey

I have them now and will make some tomorrow and over the weekend. 
Yes, big thanks to them for taking time out of their schedules for this.


----------



## mikey

tweinke said:


> For me the models and Mikey's write up together made all this angle stuff add up in my head; ... if I need or want to grind different angles I will grind new tools.



Todd, Duane, thank you for your kind words. This is what I had hoped to see - clarity, and the ability to make tools that do what you need them to do.


----------



## tweinke

I'm sure more questions will pop up from me, Most of my work is just for repair or fun no real extreme accuracy required which has been nice because that way I set the bar as to how accurate things are. The bar is usually very high and you will never imagine how long it will take to do simple things. If the part is for someone else I always ask them for tolerances then do my best to exceed what they ask for. If they knew the quality of some of my measuring tools or the lack thereof  they might think twice. I have noticed that at least on the lathe with my "new" tools accuracy seems easier to hold. As far as Bonehead goes he sounds like a good guy to know even if he is a bit hard to get along with, lucky he isn't a practical joker.  Something I remember that was funny from about a year ago a friend of the family asked if I could drill a hole through a pin for him I told him sure draw me a picture with dimensions and what not and drop it off which he did promptly. Did you guys know you can drill a .750 hole through a .500 piece of shaft, I handed him a baggie full of chips the next day and he asked what that was all about. We got a big laugh when I showed him the "blueprint" he gave me and then I gave him the .750 shaft with a .500 hole.


----------



## mikey

Cracked me up! I have to remember that "bag of chips" trick when someone gives me a drawing with stupid dimensions on it. Most of my friends tell me they want it exactly something and then give me measurements in 32nds of an inch. They do not speak machinist.

You guys would actually really like Bonehead. He is a no-nonsense kind of guy with a low BS-tolerance but once you get to know him he sort of grows on you ... like a fungus. Everyone who does know him well respects him, as do I.


----------



## tweinke

My son who knows better and does CAD work for a living gave me a really nice set of drawings one night drawn on scrap paper with a grocery list on the other side and said make these parts. Asked what the tolerance level was he replied +or- 1/4 inch I'll make them fit. Parts were plates to tie construction lumber together for a hog barn repair. Honestly that's even a bit loose tolerance wise for me


----------



## q20v

Hey guys,

Just got the tool bits in the mail today. I picked up some key stock last week and the grinder is ready to go, so I'll get started on my copies soon and have them out on Tuesday (Monday is Thanksgiving).

Dave, thanks for volunteering to send them up north! It is greatly appreciated.

I'll post pics up once I get some grinding done.

Mike's grind:



Barry


----------



## Z2V

Glad to hear that you received them


----------



## ddickey

I'll be forwarding the ones I have on Monday.


----------



## DHarris

Hey Barry,  Glad they showed up - - finally - - 10 days to get to you!

Now that you have them in hand & mike's write-ups it's going to be a piece of cake!

Glad I could help!

Dave


----------



## q20v

Tell me about it, my wife normally checks the mail during the day and I was often going in the evening in case stuff got delivered late for some reason. Just the other day she asked what I was all excited about and when I told her (tried my best to explain) what I was expecting she rolled her eyes and shook her head. Today I showed her the tools and she had a good laugh "You've been waiting for those three little things?!?!"
Some people just don't get it!


----------



## Z2V

Well, tonight I ground a left hand square tool to put in my small flycutter. It cut great and the finish was more than acceptable. I started with a small nose radius and will add to that tomorrow to see that what effect it will have. The tool is about 2" diameter and I was spinning it at 400 rpm cutting mild steel. I will also try different spindle speeds while I'm at it tomorrow  just ran out of time tonight.


----------



## mikey

Keep us posted on your LH tool, Jeff. A square tool should work, especially since the relief angles are increased. It may help to increase your back rake to focus the forces at the tip; I would try 18 degrees and see if it helps. In fact, I would try increasing back rake and see if it alters the finish. Then try increasing the nose radius after that. I will bet that increasing the back rake will do more than increasing the radius will.


----------



## Z2V

Will do Mike, I'm thinking of trying different spindle speeds then going to the tool. I'll grind the 18* and give it a shot, then adjust the nose radius.


----------



## q20v

Hey guys,

I finished my copies of the turning and knife tools today. Gotta say, Mike's instructions were pretty clear and easy to follow. While the process was simple, it still took me a bit of time to get the setup correct on my grinder. I have a small 6" grinder with basic tool rest, which I modified slightly to make work. There are locking teeth on the rest which secure it at ~15* increments, but using Mike's tool as a reference I found it wasn't close enough. So I put a washer between the teeth to allow for unlimited adjustment.

I also used a ball point pen for layout lines on the tool rest surface, which cleaned up nice using Dykem fluid remover.

Having Mike's tools in hand made replicating them very easy. I used them to compare side by side with my tools as I progressed, and to setup the tool rest angle (15*). Also, for getting the layout lines established.

The next steps for me are to replicate the grind using HSS, which I may try tonight after the kids go to bed, and then try it out on various materials. I have some DMT credit card sized diamond sharpeners on order from Amazon, based on Mike's recommendation. 

Mike, thank you very much for taking the time to make these tools for us to look at. As mentioned, having them in hand was extremely valuable and educational! Thank you thank you thank you!

Jeff, thank you very much for organizing the distribution of the tools! I'll package Mike's tools up and have them out tomorrow. I'll drop you a PM once they're gone.

Dave, thanks again for sending them to me!







Knife tool: Mike's on the left, mine on the right. I don't have a radius on the nose yet.



Turning tool: Mike's on the left, mine on the right.



Another angle of the turning tool. Mike's on top.



Turning tool, Mike's on the left.



Knife tool, Mike's on the left.



Barry


----------



## Z2V

Great job Barry, I can't tell the difference in the two
I agree, Mikey's write up is so easy to follow


----------



## mikey

I agree, Barry, its hard to tell which one is mine - you did a great job! It took me a long, long, long time to get my tools to look like yours and I am totally stoked that you guys are able to do this so fast. I've written a lot of stuff about tool grinding but it wasn't enough; it took the models to make it gel, or at least it looks that way.

Thank you for your kind words, Barry and Jeff, but more than that, I am thrilled with your success!


----------



## bfk

After some time off to deal with a nasty allergy, I tore open the package of the sample tools last night and decided to try my (totally inexperienced) hand at grinding some tools. It didn't take long to realize that I need a much more stable and secure grinding situation. Resting the grinder on my lap was apparently a bad idea. Just kidding.

The rest on the grinder only adjusts in one direction, so setting it to 15 degrees was impossible. I have another grinder that does adjust in two planes, but the wheel on it is the one that was there when it came from craigslist. It seems to be made of uncuttium.

So as a mature adult I decided to wait until I could get my setup fixed. Yeah, right. Tonight I went back down and cut the right hand tool using both grinders. It was  a pain, but the alternative was waiting, and where's the fun in that? Anyway, I got it done. It's not nearly as pretty as Mikey's or Barry's, but I thought I'd give it a try. I had made a 1/4" version for use on my Sherline. All I can say is WOW! Either this really works or someone  snuck into the basement softened the piece of aluminum I grabbed out of the pile.

As a total newbie I had bought a cheap set of indexable tools from eBay or Amazon, or wherever, thinking that this is the newer technology---it must be better. (I should know better at my age.) They work, I've made a few things successfully and learned to live within the limits of the machine and my lack of skill. Cutting 6061 T6, I could reliably take .020 cuts and get a decent finish. With my first attempt at Mikey's HSS tool I can take .050 cuts in the same material. Colour me amazed. And very grateful.

Now to get some grinding wheels of a known quality. I think my Santa is list is already full, so I don't think CBN is in my near future, but probably some Norton AO wheels will make this much easier. And a proper adjustable tool rest. Maybe I'll try making one, I know I saw some plans on this site somewhere.

Huge thanks to Mikey for a major chunk of my machining education.


----------



## Z2V

BFK
I put this tool rest together after Mikey started this project so that I could get full benefit from it. Real simple and fully adjustable. It's aluminum except for the table that is steel. 

Bf


----------



## mikey

bfk, thank you for your kind words. I really appreciate the sentiments from you and all the other guys. 

May I suggest you change from 1/4" tool bits to 3/8"? I think you will find that the Sherline lathe responds very well to a stiffer bit, and you will see this when you take fine finishing cuts; your accuracy goes way up. 

The maximum depth of cut a tool will produce is great but quite honestly, I don't often cut that deep. I know the tool can handle it but why waste material? What really matters to me is how accurately I can turn with that tool. If you keep the nose radius down to about 1/64" or so, the square tool will size accurately enough to come in dead on size most of the time. The cool thing is that when you have a half-thou to take off, it will take that much off, too. Try interpolating your depth of cut to 0.00025 and, if the tool is sharp, it will take that off the diameter. 

Cutting force reduction isn't just about how deep you can go; it is also very much about how that reduction enables very fine cuts. This is why I keep saying that for a small lathe, HSS is often the better option - accuracy!

Anyway, good for you, bfk! Keep grinding, experimenting and enjoying your lathe. 

Mike


----------



## mikey

I was corresponding with one of the guys tonight and mentioned how to hone a tool. I am reproducing that advice here. Please don't be insulted by this; it is simply my way and I thought you might find it useful:

Use an extra-fine diamond stone and water to lube it. Be sure the stone is clean; wash with Ajax or similar first and get it clean and flat.
If you can, submerge the stone in water and then place it on a solid surface.
Bring the side cutting flat into contact with the stone and make sure it sits dead flat, no rocking. Gently stroke towards you. Going back and forth will make you rock the tool and you will round the flat. Just pull and apply gentle even pressure. You are not trying to grind the surface; you are simply honing it.
Do the same to the end cutting face. Be careful not to tip the tool; just keep it flat and pull lightly. EDIT: I should tell you that your goal is to raise a burr at the top of the face you're honing. You will remove this burr in the next step.

Finally, hone the top of the tool. You MUST keep this flat. It usually only takes a few strokes per face to hone (EDIT: to remove the burr) the tool.
Do not touch the nose radius unless it is getting too small. If you need to recut it, go easy and try to keep the radius even from top to bottom and side to side.
You can cut all kinds of facets if you are careless in how you hone your tools. It doesn't take a lot of pressure to hone HSS. More strokes is better than heavy pressure. When an edge is sharp it will not reflect light. If you look at the side cutting edge and see a band of bright reflected light then your tool is not sharp; hone it until the light is gone.

Remember that it is easier to hone a tool at the end of the day than it is to let it get dull and have to regrind it.


----------



## q20v

Thanks guys. I've ground a few tools in the past using the SB "How to Run a Lathe" for guidance, but I never put that much time or effort into the grinder setup. I also used to just guess at the angles. I didn't get a chance to grind HSS last night but am excited to do so.

Mike, thanks for the honing tips. I've always dragged the tools across the abrasive so that a burr would be left on the dull end, i.e. the sharp edge leading the drag across the stone, if that makes sense.. No rhyme or reason for this, just what I thought was right. Should I drag the opposite way? Or does it matter?

Barry


----------



## Z2V

I still have a set of Mikey's tool models in Canada. If there are any of you guys in Canada that would like to get in on this shoot me a PM. 
Thanks 
Jeff


----------



## mikey

q20v said:


> Thanks guys. I've ground a few tools in the past using the SB "How to Run a Lathe" for guidance, but I never put that much time or effort into the grinder setup. I also used to just guess at the angles. I didn't get a chance to grind HSS last night but am excited to do so.
> 
> Mike, thanks for the honing tips. I've always dragged the tools across the abrasive so that a burr would be left on the dull end, i.e. the sharp edge leading the drag across the stone, if that makes sense.. No rhyme or reason for this, just what I thought was right. Should I drag the opposite way? Or does it matter?
> 
> Barry



I try to raise a burr on the top of the tool, Barry. That way, when I hone the top surface I take that burr off, leaving a sharp edge behind. After shaping the tool on the belt sander, I hone really carefully with the coarse stone. I am looking to get the coarse grind marks off without changing the angles of the face, creating facets or grinding down an edge. When I go to the fine stone, all I want to do is remove the marks from the coarse stone. Same with the extra-fine stone, but here I am making sure that I have zero light reflecting off the cutting edges. Once I get that, I stone the nose radius on and hone the top surface again and the tool is ready for use. It normally takes me far longer to hone a tool than to shape a tool.

A tool sharpened this way will shave hair, cut meat and will definitely cut metal. If I shaped the tool with the right angles, it will stay sharp for a long time. As I work, I keep an eye on the edges. If I see reflected light (which I rarely ever do), I stop and hone it with a few strokes; takes all of 15 seconds to do. Most guys don't pay much attention to their edges but once you see how a sharp tool cuts you will begin to. When you're trying to come in on size on a critical part take the time to sight your edges because a dull edge will deflect and this affects your accuracy.


----------



## Bamban

In support of the Junior shooting program Mike donated a couple of Rex AAA cutters he made, one knife and the standard turning to cuts 416R SS specifically. Following Mike's instruction on angle of attack of the turning tool, made turning 20 inch barrels a lot easier, played with the angle till i got the results. Pointing the cutter towards the chuck when roughing and the other way finishing is the key, which I never practiced before with indeaxble carbide bits.

The knife tool is excellent in cutting or finishing the tenon shoulder. I needed to adjust the headspace on one barrel 0.0005, decided to use the knife tool, touch off the tenon, monitoring the tool post with 0.0005 indicator, moved the carriage and cut. And it indeed shaved off 0.0005 on the tenon shoulder.

On Mike's suggestion I will grind my own and duplicate and save his for models to copy.  The first one I will duplicate is the knife tool specifically for cutting crown 


Mike, thank you.


----------



## mikey

Bamban said:


> In support of the Junior shooting program Mike donated a couple of Rex AAA cutters he made, one knife and the standard turning to cuts 416R SS specifically. Following Mike's instruction on angle of attack of the turning tool, made turning 20 inch barrels a lot easier, played with the angle till i got the results. Pointing the cutter towards the chuck when roughing and the other way finishing is the key, which I never practiced before with indeaxble carbide bits.
> 
> The knife tool is excellent in cutting or finishing the tenon shoulder. I needed to adjust the headspace on one barrel 0.0005, decided to use the knife tool, touch off the tenon, monitoring the tool post with 0.0005 indicator, moved the carriage and cut. And it indeed shaved off 0.0005 on the tenon shoulder.
> 
> On Mike's suggestion I will grind my own and duplicate and save his for models to copy.  The first one I will duplicate is the knife tool specifically for cutting crown
> 
> 
> Mike, thank you.



Thank you, Bamban. With your consent, can I post the angles for the tools so others can duplicate them for working 416R? It will be a good exercise to show how we chose the angles we chose and thanks to you we know we have a working tool that others can duplicate for their work. What do you think?


----------



## Bamban

Go for it.

Thanks


----------



## mikey

Okay, Bamban and I discussed his work before deciding on what tool geometry to use. He is turning 416R stainless steel rifle barrels. (I have not turned 416R before.) It comes prehardened to somewhere between Rc 24 to 36 so maybe semi-hard. Like all stainless steels, 416R will work harden so we needed a tool that would cut with lower forces to keep the tool from bogging down in the cut and producing heat. We also needed to clear the chips out fast to keep cutting temps low. Most of the work is general turning and facing but rather than just make a turning tool, we chose to make a general purpose tool and a knife tool.

HSS can cut 416 but a tungsten cobalt tool would handle the heat and abrasion better. We chose a Rex AAA bit because it has 5% cobalt but 18% Tungsten, the highest tungsten content of any bit made by Crucible. This would allow the tool to handle high heat and abrasion.

Here are the specs we chose:

Side and end relief = 15 degrees
Side rake = 25 degrees
Back rake = 10 degrees
The relief angle of 15 degrees is about 50% more than called for in this material. I chose this to reduce cutting forces but also to improve the finishes. By lowering forces, the tool should cut more freely and this should reduce heat.

The side rake is 7 degrees more than the angle table calls for. The goal is to greatly improve chip clearance while also reducing cutting forces. Given that the relief angles are increased and side rake is also boosted, the risk of reducing edge life is a real thing so I encouraged Bamban not to hog with this tool.

Back rake is increased by only a few degrees. This is intended to keep the cutting forces focused juuust to the side of the nose radius. It would have been nice to increase back rake more but then we would need a larger nose radius to finish well and this would lead to deflection, less cutting action and more heat production so I opted for more side rake and kept back rake reasonable. Focusing the forces here will enable the tool to rough well and face very accurately.

We chose a general purpose shape and a typical knife tool shape but used the angles above for both tools. The nose radius on the turning tool was held at about 1/64", while the knife tool radius is smaller than that. The reasons for these radii are to reduce radial forces to improve accuracy first; finish is a secondary consideration. If a better finish is required, the nose radius can be increased.

This is an example of how we can take a general purpose turning tool shape and alter its geometry to accommodate the peculiarities of the material. I will admit that since I haven't turned this material myself, the angles chosen were a guess ... but it was an educated guess. We chose a tool blank with the desired properties so it should hold up under frequent use; I think we chose well. Here are the tools right off the belt sander:




My thanks to Bamban for allowing me to share the specs on his tools. I wanted to show you how a tool blank was selected and how the angles were chosen. Bamban already told you how he altered lead angle to both rough and finish, which is helpful.

Now we have a tool that is proven to work with 416R. If you have a tool geometry you would like to share, please feel free.


----------



## q20v

Hey guys,

I had a bit of time tonight to try the RH turning tool on a piece of Cleveland Mo-Max HSS that I had. I copied my copy of Mike's turning tool pretty much exactly, which took some time to accomplish considering my small grinder and Mo-Max is a tad harder than key stock... anyway, got it done and spent a decent amount of time honing, first by practicing on my key stock bit, then carefully on the HSS. Mike, I tried both honing techniques we discussed above and I felt I had better control doing it the way you suggested, basically piling up the burr (even though none really built up) on the cutting edge, then taking it off by honing the top.

The DMT plates I ordered arrived today and worked very well. (don't mind the shape of the back of the bit, I bought it used at a second hand store)



This is the new grind next to my previous attempt, using the South Bend manual as a rough guide. It worked with mixed results.



Please let me know if anything can be improved, particularly with the honing. I'm using a 6" grinding wheel so the hone is only really touching the edges.



Looking at this picture now, I kind of see a band of reflected light on the top edge. Is this what you're talking about trying to avoid, Mike?




I was almost going to stop there and go to bed, but I had to give it a try. The deeper cut is with very little lead angle (~10*) and the 1.25" piece of 6061T6 sticking out way too far. There are chatter marks on the surface as a result. Second cut (shiny one) is with a greater lead angle (as pictured) and the bar pulled into the chuck. Very very nice finish!!



Then I tried a piece of 1.5" mild steel. Same increased lead angle as before. Same impressive result on the surface finish. Then I put it to the test and successfully took less than .0005 off the diameter. Barely a hair of material came off the bar. Wow! Can't say I've ever done that before.




Maybe tomorrow I'll give the knife tool a try on some HSS. Gotta say I never thought I'd be putting so much time into grinding HSS, but I'm having a great time doing it now that I have some good direction!

Barry


----------



## mikey

Grinding HSS is a bit different than keystock, isn't it? There will be a tendency to push harder and grind faster but I suggest you not do that with a wheel. Take your time, dip the tool in water to keep it cool and it will get there eventually. 

You need a larger nose radius on the tool, Barry. Try for a 1/64" to 1/32" radius and the tool will finish much better for you. 

As for honing, yeah, when you grind with a small wheel it will tend to create a scallop on the flat. A belt will not do that. You need to flatten the entire side cutting edge, from the tip back to where the back rake curves up. This will give you the entire side cutting edge to work with. Same for the end face; you should catch the entire edge. The top should be honed so that the side and end edges are clean, sharp and do not reflect light. 

The reflected light I was referring to will be on the edge created by two planes as they intersect, both the side and end. 

Try honing the tool well, then align the shank of the tool perpendicular to the work to rough. If it chatters, which it won't, then turn it slightly more toward the chuck. If you want to size the work then turn it more toward the tailstock. You have to mess with it but the tool will tell you when its right; it will cut smooth and clean with a good finish. 

As for taking a fine cut, yeah, this tool can take a very fine cut. I've dialed in a 0.0001" depth of cut (using a dial indicator) and cut it with the square tool so I know it can be done. 

Good work, Barry! You went from newbie guy to tool grinder in a matter of days. It takes time to hone your skills so be patient and it will come.


----------



## mikey

I just re-read my post above and it is unclear. Barry, you need to hone the faces but you do not need to flatten the face with the hone. Only the upper and lower edges will be honed and that is just fine but try to catch the entire cutting edge. Sorry, Barry.


----------



## mikey

I was queried tonight about how a square tool cuts as you turn into a shoulder. As I stated before, most of the cut is made with the nose radius but the end cutting edge is also involved.

The tip geometry of a turning tool is actually rather complex but basically you have two cutting edges joined by a nose radius. You have the side cutting edge, which is comprised primarily of the side relief and side rake angles, and you have the end cutting edge that is comprised primarily of the end relief and back rake angles.

When turning normally, the side cutting edge is the primary edge used. However, when turning into a shoulder, the end cutting edge is primary. You can see this in the pic below; the side of the nose radius and the adjacent end cutting edge is in contact with the work:




What actually happens is that the end cutting edge cuts like a facing tool and this has the potential to produce very good finishes. However, there is also a fair amount of edge in contact with the work so cutting forces increase. Therefore, when turning into a shoulder, lighten up on your depth of cut and you will retain your accuracy and finish. Go too deep and you get deflection and can produce chatter due to the edge contact. What I do is rough until I am about 0.005 - 0.010" from final size and then change my lead angle like in the picture so I can get into that corner. Then I can reduce depth of cut and sneak up on the final diameter; works good.

This is one reason why I recommend you make the side and end relief angles the same; doing this reduces cutting forces and it makes a difference when taking light cuts into a shoulder. While this is yet another thing to remember, you will eventually learn to reduce your depth of cut in this situation without even thinking about it. At least now you know why you're doing it.

Edit: the work piece in the pic is a prop and was not being turned. An actual cut would produce a mirror finish.


----------



## q20v

Mike,

Thanks for the feedback!

Nose rad: Definitely agree with you. It was awkward trying to put the small radius I have on the tool, as I'm essentially freehanding it on the grinding wheel. Although the surface finish is pretty good in the pictures, that was at the slowest feed rate and there is still a discernible line around the work piece (more evident in person). Embarrassingly, I never thought to re-adjust my grinder tool rest angle so that I don't have to freehand the initial cut (small flat) for the nose rad. I'll try that tonight and carefully round the cut with the DMT plates.

Honing: I think I'm honing just the point of the side cutting edge because that surface may not be perfectly flat (not talking about the grinding wheel scallop, but the length from the tip of the tool, back), the pressure I was putting on the tool while grinding was likely inconsistent as I moved across that surface (grinder wheel is about 3/4" thick). I'll put a straight edge across it tonight to see how flat it is.

I'll try again tonight and report back with the results.

Barry


----------



## mikey

q20v said:


> Mike,
> 
> Thanks for the feedback!
> 
> Nose rad: Definitely agree with you. It was awkward trying to put the small radius I have on the tool, as I'm essentially freehanding it on the grinding wheel. Although the surface finish is pretty good in the pictures, that was at the slowest feed rate and there is still a discernible line around the work piece (more evident in person). Embarrassingly, I never thought to re-adjust my grinder tool rest angle so that I don't have to freehand the initial cut (small flat) for the nose rad. I'll try that tonight and carefully round the cut with the DMT plates.
> 
> Honing: I think I'm honing just the point of the side cutting edge because that surface may not be perfectly flat (not talking about the grinding wheel scallop, but the length from the tip of the tool, back), the pressure I was putting on the tool while grinding was likely inconsistent as I moved across that surface (grinder wheel is about 3/4" thick). I'll put a straight edge across it tonight to see how flat it is.
> 
> I'll try again tonight and report back with the results.
> 
> Barry



Barry, I suggest you not use your grinder to put a nose radius on your tools; it is very difficult to do this under power. Use your fine or extra-fine diamond stone to do it manually. Just grind an even flat at the nose that extends from the top of the tool to the bottom, making it just slightly narrower than the nose radius you want. Then gently round the sides of the flat and blend it into the side and end faces. 

Maybe consider using a belt sander as a tool grinder. I will try to find the time to use ceramic belts on my 1/3HP Craftsman belt sander to see if they will allow that machine to grind tools. If it does then we have a cheap and readily available option for a machine that will work. I'll get on it soon.


----------



## q20v

Hey Mike,

Okay, I follow you now. I'll give it a go manually. That edge is tricky to radius because it's curved (end and side faces are scalloped from the grinding wheel). And I hear ya about the belt sander. I will have to keep my eye out for one.

Barry


----------



## Bamban

Mike,

I have to admit, I learned from your posts and the personal messages you sent me. In the past I always use the indexable carbide bits with the holder just butted up against the inside of the wall of the cut out, basically straight forward into the workpiece and just let the holder and the bit design do their thing.

I have a barrel in one of the lathes, the 1236, that has been sitting there since I encountered the anomoly of the QCGB. Just out of curiosity I played with the bit angle of attack. Here is a short video as I made the finishing pass, cleaning up the previous roughing cut. Notice the bit holder is kicked back towards the TS side. Did not move the QCTP, just adjusted the angle of the bit holder. Notice the finish.

Thank you for all the tutorials.


Nez

Watch "Finishing Pass Cutter Towards TS" on YouTube


----------



## Randall Marx

Hi Mike
Thanks again for taking the time and putting forth the effort to help all of us with this endeavor! I have a question regarding the grinding tool. I am currently stuck with a bench grinder to use for grinding my tools. Using the periphery of the wheel to grind, where do I need to set the angle in relation to the tool? Does the 15-degree tangent need to fall at the top, middle, or bottom of the tool? In other words, If I match your example to my grinder, would I set the table angle with the wheel _actually_ touching the ground face on the top or what? I ask because the tangent location will change the apparent angle of the ground face as seen by the workpiece being cut in the lathe.
Thanks again for your guidance.
Randall


----------



## mikey

Bamban said:


> Mike,
> 
> I have to admit, I learned from your posts and the personal messages you sent me. In the past I always use the indexable carbide bits with the holder just butted up against the inside of the wall of the cut out, basically straight forward into the workpiece and just let the holder and the bit design do their thing.
> 
> I have a barrel in one of the lathes, the 1236, that has been sitting there since I encountered the anomoly of the QCGB. Just out od curiosity I played with the bit angle of attack. Here is a short video as I made the finishing pass, cleaning up the previous roughimg cut. Notice the bit holder is kicked back towards the TS side. Did not move the QCTP, just adjusted the angle of the bit holder. Notice the finish.
> 
> Thank you for all the tutorials.
> 
> 
> Nez
> 
> Watch "Finishing Pass Cutter Towards TS" on YouTube




Yup, lead angle is a real thing. Most guys who use inserted carbide don't even realize that just because the tool has clearance angles on the side and end, that doesn't mean you have to use the tool that way. Try using a CCGT AK insert turned toward the tailstock in aluminum - the finish will like to frost your eyeballs.


----------



## mikey

Randall Marx said:


> Hi Mike
> Thanks again for taking the time and putting forth the effort to help all of us with this endeavor! I have a question regarding the grinding tool. I am currently stuck with a bench grinder to use for grinding my tools. Using the periphery of the wheel to grind, where do I need to set the angle in relation to the tool? Does the 15-degree tangent need to fall at the top, middle, or bottom of the tool? In other words, If I match your example to my grinder, would I set the table angle with the wheel _actually_ touching the ground face on the top or what? I ask because the tangent location will change the apparent angle of the ground face as seen by the workpiece being cut in the lathe.
> Thanks again for your guidance.
> Randall




This is a difficult thing to answer because a lot depends on how the tool rest is situated. Some grinders allow the top of the rest to be at the centerline of the motor spindle; this is a true zero. Most don't do this so who knows where zero is, much less where 15 degrees is. This is one reason why many of us use an independent rest that is not attached to the grinder. Examples are like the one Jeff/ @Z2V  made, or the Veritas rest or the Glendo Grind-R rest.

For grinding the model tools, I would just butt the face of the tool to the wheel and set the rest to duplicate the angle as close as you can. That's why I made a physical model. That angle should allow you to duplicate the three tools. Then, when you have time, you can sort out how you want to make your own rest or choose one to buy.

Sorry to be of no help, Randall. I ground tools on a bench grinder for 10 years and hated it the whole time. The rest was one of the reasons for hating it. A belt sander works better for me.


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## Doubleeboy

Hey Mike, Thank you for all the great work you have done.  Do you think this belt sander below would do the job, its on sale thru tonight.

https://www.zoro.com/dayton-beltdisc-sander-13-hp-120v-6y945/i/G2309045/

Thank you for your input
michael


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## mikey

Doubleeboy said:


> Hey Mike, Thank you for all the great work you have done.  Do you think this belt sander below would do the job, its on sale thru tonight.
> 
> https://www.zoro.com/dayton-beltdisc-sander-13-hp-120v-6y945/i/G2309045/
> 
> Thank you for your input
> michael



Hey Mike. Its been a fun thread, hasn't it?

That belt sander is the same as the Craftsman belt sander. At 1/3hp, its pretty anemic. The basic design is great; its the same as my 1/2hp model and I know it works for tool grinding. The only issue is the weak motor. In a few hours, I will have some time to grind a tool using the exact same grinder you linked to but with a ceramic belt. If it grinds a cobalt tool adequately, I will report it here and you can make up your mind.  So, check back here in a few hours, okay?


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## Doubleeboy

Thanks Mike, I will check in after supper


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## mikey

Mike, and anyone else who is considering the 1/3hp Craftsman/Palmgren/Whoever 2 x 42 belt sander, I would like to report that a Red Label Abrasives 36 grit ceramic belt successfully and quickly ground a 3/8", 10% cobalt HSS tool bit with no problems. 

I did not grind the whole tool but I ground the entire side cutting edge, which is the biggest chunk of material you have to grind, and it ground it in under 2 minutes without stalling or slowing down. And this was with a belt that had already ground 9 model tools from keystock and 3 other HSS/cobalt tools so it was well used. In contrast, I can completely stall this motor just grinding wood with an Aluminum Oxide belt so the belt is what makes the difference.

If you are willing to commit to using ceramic belts then this machine will work for grinding tool bits. You still have to make a good tool rest and epoxy on a ceramic glass platen liner on it but I think it will suffice. With that said, if you ever find the 1/2hp version of this machine, buy it! In the meantime, this one should be okay. I warn you that I have reservations about the power of the motor but it walked right through a 10% cobalt bit rather quickly so I suspect you'll do okay with it. 

Here is a link to the mods I made to my own grinder:  http://www.machinistblog.com/modify...inch-belt-sander-for-tool-grinding/#more-5349

Feel free to copy the tool rest and platen mods, guys. The tool rest is a very good one and I have found no fault in the design so far. I am now on my second platen liner but only because a belt broke and knocked the liner loose, not because the liner wore out.


----------



## q20v

Hey again guys,

I was back at it tonight to try and touch up the RH turning tool based on Mike's feedback and I think I've made a bit of progress. I welcome the tips and hints at areas to improve so keep those coming.

I touched the side cutting face on the grinder to try and even it out. That definitely helped as seen by my honing picture below. I was able to hone the entire side cutting edge now.



I then honed the end face again:



Then the top of the tool:



And increased the nose radius by hand, using the DMT plates (fine and then extra fine):




This is the same steel bar as the previous post. The right hand band is after today's progress, the left hand band is from the other night. I think they look pretty similar but the right hand side feels a bit smoother.



I increased the lead angle and made another pass. Smoother again.



Here is the aluminum 6061T6 bar again.
Left band: same increased lead angle as the steel. Middle band: what I thought was amazing from the other night. Right band: chewed up surface from the bar sticking out too far from the other night, also with very little lead angle. So, looks like it's gotten better (left band).




Another picture with a bushing I had made a long time ago, just to compare.




Then for fun, I straightened the tool almost perpendicular with the bar and re-machined part of the end. Looks decent! Don't mind my fingerprints on the far left hand band. 



Mike, think I should try increasing the nose radius a bit more? Anything else I can do to improve at this point? Or just start using it and play around with the lead angle some more?
I also haven't tried taking any deep cuts. Might give that a go as well.

Thanks so much for everyone contributing to this thread. It's really become a fantastic resource.

Barry


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## mikey

Now your tool looks like it should, Barry, including the nose radius. Great job! I would use it as is and see how it goes. You have a decent finish now; it will be better with more lead angle towards the tailstock but you can also enlarge the nose radius a tiny bit more if you like. By the way, if you mess with the nose radius and make it too big, just grind a bit on the end cutting flat and that will remove the radius; then stone a new one on.

I would spend some time making test cuts to see how your lead angle needs to be for roughing, sizing and finishing. This will not take long at all. Also take deep cuts and shallow finish cut and see how your tool behaves in different materials. In time, you will know how your tool cuts and you'll use it without even thinking about it.

Good work, Barry. You're on your way!!

Mike


----------



## mikey

Barry, I meant to ask you what kind of lathe you're using. Do you have power longitudinal feed?


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## q20v

Thanks Mike! I have a good chunk of time tomorrow that I can dedicate to working in the garage, so I'll try the things you've suggested. I'm also thinking about the next tool to make, and instead of the knife tool I may make a LH turning tool, since I'm really familiar with the geometry right now. Although if I get as much time tomorrow as I hope, I should be able to make both.

Here's a picture of my lathe from several years ago (~2012). It's a Busy Bee DF1224G and has power feed in the longitudinal and cross directions. I was using the slowest feed rate for all the cuts above. RPM was somewhere between 6-700 if I recall?


----------



## mikey

Okay, 12" lathe. You should be able to take pretty hefty cuts with that machine. I suggest you try some decent cuts to see how the tool performs. Adjust the feeds and speeds to suit the material. If you're not sure how to do that, say so and we'll discuss it; I assure you that you are not alone in this.

You should be able to take a 0.200" deep cut (0.400" off the diameter) in aluminum and mild steel. I don't think it is necessary to go deeper unless you're curious but this will show you what the tool can do. Try this with the tool maybe 5 degrees off perpendicular with the tip toward the chuck.

Once you make the cuts, measure the diameter and turn the shank of the tool just off perpendicular towards the tailstock and take an additional 0.010" cut to simulate a sizing cut. 

Finally, turn the tool toward the tailstock another 5-10 degrees and take a 0.0005" finishing cut. This will show you the range of the square tool and what it can do.
Once you do these tests, try the same thing with your carbide tools and see what happens. You can also grind a general purpose tool with the angles found in an angle table to see how it compares to the square tool. You don't really need to do all of this but if you do, you will have a very clear idea of what your lathe can handle and the impact of a modified tip geometry.

A LH tool is a good idea. After that, maybe grind a tool specifically ground for aluminum or mild steel. We can discuss how to alter the angles if you like and this will get you on your way to learning how to modify tools for different material groups. You see, the real skill in tool grinding isn't in the grinding; its in knowing how to alter the tool angles to optimize its performance in the materials you work with.

No pressure here, Barry. You don't need to do any of this but if you choose to, I will help.

Finally, if you think you like working with HSS tools then consider buying a belt sander and make a good tool rest for it. It will make tool grinding much, much easier for you.


----------



## Doubleeboy

That is one heck of a crankshaft in photo above.  You should be proud.  Is there  a write somewhere about its construction?

michael


----------



## Metal

mikey said:


> You should be able to take a 0.200" deep cut (0.400" off the diameter) in aluminum and mild steel. I don't think it is necessary to go deeper unless you're curious but this will show you what the tool can do. Try this with the tool maybe 5 degrees off perpendicular with the tip toward the chuck.




I'm working on restoring my new lathe, but I just wanted to say that is a bonkers cut, I cant wait until I can do them myself, lol.


----------



## mikey

Metal said:


> I'm working on restoring my new lathe, but I just wanted to say that is a bonkers cut, I cant wait until I can do them myself, lol.



My Emco 11" lathe manual says that if I want to go deeper than 0.200" I need to step down the speed one notch and then go for it. This is with a conventional tool so I figured a square tool would handle it and it did with no problem. It is a big cut, though, and we won't be doing this very often because its a waste of material but its fun to try it.


----------



## q20v

Well I wish I could take credit for doing something to that crankshaft, but I had only mounted it up for fun! It's from my old Audi 5 cylinder.. a quattro, with 20 valve head... some would say, quattro 20 valve, or q20v...  

Mike, the biggest cut I've taken is about .075" DoC on heat treated 4140, bar was about 5/8" dia. using a carbide insert. It went pretty smooth and I had no real reason to go deeper at the time. But I'm anxious to give this HSS bit a try tomorrow. I will follow your guidance and report back. I'll even try taking a video.

To be honest I typically don't use feeds/speeds formulas but I suppose now is as good a time as any to learn.

Using 550 SFM for Aluminum (https://littlemachineshop.com/reference/cuttingspeeds.php) I'd be looking at 1400 RPM:
http://www.custompartnet.com/calculator/turning-speed-and-feed
That about right?

And for feed rate, the slowest my machine will go is 0.0025 IPR, should I try that or is there a more scientific approach I should be taking? I suppose it depends on what my machine can do?


----------



## mikey

Cutting speeds matter but I try to keep it simple. Instead of a calculator, I use the formula: *RPM = SFM X 3.82 / D*, where SFM is your cutting speed, 3.82 is a constant and D is diameter of the work. This works for both carbide and HSS tooling; the SFM will differ, with carbide being roughly twice the speed of HSS. Keep it simple.

The rpm derived from the formula is just an estimate of speed. Most folks go with the calculated value or the closest lower speed but with your modified tool, I would go with the next higher speed instead.

Feed is something you need to work out. It will vary with the gearing on your lathe and I would start with the lowest feed and work up until you get the result you want. When I evaluate a new tool, I don't power feed. I feed manually. I want to know what the cut sounds like, looks and feels like when I can feel a slight positive resistance to the feed. This tells me what to expect when things are right for that material, tool and lead angle.

Big depths of cut is an ego thing for the most part. We should be starting with stock close to our final diameter to reduce waste. However, its fun to see what a tool can do. If you like, try a 0.100" deep cut in aluminum and work up from there. I think you will be surprised how big a cut your square tool can handle in aluminum; I've gone up to 0.25" without even slowing down the lathe and I'm sure it can go deeper.

Do the same with mild steel; start low and go up. You will find that when the lathe slows or chatters, you need to drop down a speed but the lathe will make the cut. Play with it and see. Your square tool is capable of much more than you think.

Keep in mind that when a tool chatters you should first reduce your lead angle a bit. If that fails, reduce speed and increase feed and that will handle it.

Let me know if this is at all unclear.


----------



## q20v

No, Mike, that is perfectly clear and is great guidance to follow. I'll play with it tomorrow and let you know how it goes. Many thanks for taking the time to explain everything in the detail that you do. I've been using the lathe for about 5 years now (intermittently) and although I feel like this is somewhat back to basics, it's obviously something I never had a good grasp on. I've been getting by for my non-critical parts, but now that I have a better grasp on what the lathe can do, I'm starting to think of more complex projects, and getting these basics locked down, I think, is vital.


----------



## mikey

q20v said:


> No, Mike, that is perfectly clear and is great guidance to follow. I'll play with it tomorrow and let you know how it goes. Many thanks for taking the time to explain everything in the detail that you do. I've been using the lathe for about 5 years now (intermittently) and although I feel like this is somewhat back to basics, it's obviously something I never had a good grasp on. I've been getting by for my non-critical parts, but now that I have a better grasp on what the lathe can do, I'm starting to think of more complex projects, and getting these basics locked down, I think, is vital.



When I'm looking for an answer, the worst thing that happens is when someone tells me what but doesn't tell me why or how or when. I hate that. That's why most of my answers will be fairly complete so as to not leave you in a lurch. I mean no offense.

It's funny but whenever I have a machining issue, its usually something basic that I didn't attend to. So yeah, basics, I like basics.


----------



## tweinke

mikey said:


> When I'm looking for an answer, the worst thing that happens is when someone tells me what but doesn't tell me why or how or when. I hate that. That's why most of my answers will be fairly complete so as to not leave you in a lurch. I mean no offense.
> 
> It's funny but whenever I have a machining issue, its usually something basic that I didn't attend to. So yeah, basics, I like basics.



    And that's why this has been a very good thread with lots of good learning. This has been one of those learning experiences where the teaching vs doing it for someone has really paid off. ( Teach a man to fish...........)


----------



## mikey

tweinke said:


> And that's why this has been a very good thread with lots of good learning. This has been one of those learning experiences where the teaching vs doing it for someone has really paid off. ( Teach a man to fish...........)



Thank you, Todd. I'm waiting for someone to modify a tool for specific material so we can go through the thought process. I mentioned it when I discussed the tools I made for @Bamban; he has a short video he can post if he feels it appropriate that shows how the chips come off (vs his carbide tool) and where the chips come off at the tip. The tool does what we wanted it to do and the video shows it. I will leave it to him.


----------



## Z2V

I'm looking forward to getting in on some of this fun. I've got some work in front of me but shouldn't take too long.
If you care to take a peek and confirm my dummy of the day,
http://www.hobby-machinist.com/threads/my-pm-1236-precision-arrived-today.63106/#post-519965

Q20V
I looked at the pic of your crankshaft chucked in your lathe and thought my eyes were playing tricks on me. I looked and counted and looked and counted but all I could come up with was five!!!


----------



## HBilly1022

Mikey, I just discovered this thread and read through the whole thing. I want to thank you for your generosity in putting this together and providing on line instruction classes for us novices. This thread is extremely informative and easy to follow. Your pictorial sequence of how to grind tools is priceless and the information of how the lead angles affect the finish is great. I have hit and miss success with getting decent finishes (mostly miss) but I can now understand some of the issues I have been missing. I believe your tutorial will put me on the right path to producing better finishes.

Thanks again for all your effort and sharing your knowledge with us.

pm sent to Z2V to be in the Canadian loop for the sample tools.

I have one question if you don't mind. Do you think a 2" x 28" belt sander would suffice. The only 42" sander I can find anywhere near me is $775 and I'm not willing to spend that. There is a 1/2 hp 2" x 28" sander on sale at Busy Bee for $130 and I'm hoping the shorter belt would be ok or do you think it would heat up too much. I've been toying with the idea of building a 2" x 42" or even a 2" x 72" sander but would prefer to just get the 2" x 28" if it would be adequate. I have a 1" x 30" sander and use that for some sharpening tasks.


----------



## mikey

HBilly1022 said:


> Mikey, I just discovered this thread and read through the whole thing. I want to thank you for your generosity in putting this together and providing on line instruction classes for us novices. This thread is extremely informative and easy to follow. Your pictorial sequence of how to grind tools is priceless and the information of how the lead angles affect the finish is great. I have hit and miss success with getting decent finishes (mostly miss) but I can now understand some of the issues I have been missing. I believe your tutorial will put me on the right path to producing better finishes.
> 
> Thanks again for all your effort and sharing your knowledge with us.
> 
> pm sent to Z2V to be in the Canadian loop for the sample tools.
> 
> I have one question if you don't mind. Do you think a 2" x 28" belt sander would suffice. The only 42" sander I can find anywhere near me is $775 and I'm not willing to spend that. There is a 1/2 hp 2" x 28" sander on sale at Busy Bee for $130 and I'm hoping the shorter belt would be ok or do you think it would heat up too much. I've been toying with the idea of building a 2" x 42" or even a 2" x 72" sander but would prefer to just get the 2" x 28" if it would be adequate. I have a 1" x 30" sander and use that for some sharpening tasks.



Thank you for your kind words, HBilly, and you're welcome. I'm sure Jeff can get a set of tools in your hands and I hope they help you. When you get them, share your efforts and results. If I can see what you're doing, I can help you fine tune things so they work as they should. 

I think a 2x28 belt sander will work just fine. As long as you can access the right side of the platen, build a good tool rest and hopefully fit a ceramic glass platen in there then the thing will grind tools. You must be sure the entire right side of the platen is open - no housing or covers or anything that interferes with getting the tool bit right up on the right side of the platen.

Welcome to the thread, HBilly. If you have questions, ask them, please. I honestly tried to put it all in this thread but I may have missed something. No, I'm sure I missed something, so if you are not sure about something, ask. I guarantee you that some silent guy out there has the same question but won't ask it.

Mike


----------



## HBilly1022

Here is a link to the 2" belt sander I'm looking at. https://www.busybeetools.com/products/grinder-and-sander-8in-x-2in-combo-craftex-ct169n.html  It doesnlt look like the right side is entirely open and the platen looks kind of wide which would likely interfere with grinding at the edges of the belt.


----------



## Z2V

HBilly
I have you on the list. I'll give you a PM when they ship to you with info on who to forward to.
Welcome aboard 

Jeff


----------



## mikey

HBilly1022 said:


> Here is a link to the 2" belt sander I'm looking at. https://www.busybeetools.com/products/grinder-and-sander-8in-x-2in-combo-craftex-ct169n.html  It doesnlt look like the right side is entirely open and the platen looks kind of wide which would likely interfere with grinding at the edges of the belt.



It looks like there is a cover on the right side; that can come off so you can access the right side of the platen. However, the platen looks like just a flat plate that screws in place. If you can figure out how to get a reliable platen with a liner in there, it might work. Is this thing somewhere you can go look at it and maybe take better pics?


----------



## HBilly1022

mikey said:


> It looks like there is a cover on the right side; that can come off so you can access the right side of the platen. However, the platen looks like just a flat plate that screws in place. If you can figure out how to get a reliable platen with a liner in there, it might work. Is this thing somewhere you can go look at it and maybe take better pics?



Busy Bee is about 5 to 6 hrs drive but there is a similar looking one at Princess Auto which is closer and I will take a close look at it on Monday when I go to the big City. Not sure 28" is a good size to get now. I read some comments on the Busy Bee site that the belts are very hard to find. I did some searching and only came up with 2 suppliers, Busy Bee and Princess Auto. Pretty limited selection too. Might have to consider using my 1" x 30" for now and building a 2" x 42" so I can get a better selection of belts. Great another project to put on the list, lol.


----------



## mikey

HBilly1022 said:


> Busy Bee is about 5 to 6 hrs drive but there is a similar looking one at Princess Auto which is closer and I will take a close look at it on Monday when I go to the big City. Not sure 28" is a good size to get now. I read some comments on the Busy Bee site that the belts are very hard to find. I did some searching and only came up with 2 suppliers, Busy Bee and Princess Auto. Pretty limited selection too. Might have to consider using my 1" x 30" for now and building a 2" x 42" so I can get a better selection of belts. Great another project to put on the list, lol.



Is there any way to make the platen on the 1x30 more solid so it cannot flex? Can you epoxy on a glass platen liner to it? If so, that may suffice for now. 

Here you go:http://usaknifemaker.com/ceramic-glass-platen-liner-flat-platen-1-x5-x-0-192.html


----------



## HBilly1022

mikey said:


> Is there any way to make the platen on the 1x30 more solid so it cannot flex? Can you epoxy on a glass platen liner to it? If so, that may suffice for now.
> 
> Here you go:http://usaknifemaker.com/ceramic-glass-platen-liner-flat-platen-1-x5-x-0-192.html



Thanks for the link Mike. I'll check to see if I can find a Canadian supplier (the border thing can be a hassle and expensive too .... that's another story).

 As for stiffening the 1" x 30" platen, I'm sure there's a way if the will is strong enough. I also have 2 grinders and 6" x 48" sander that I can use. The 6" sander backing plate is solid steel (no flex) but I couldn't use it for the top rake. Probably use a grinder for that until I get a better setup.

John


----------



## brino

Here's a manual for the Busy Bee 2x28" CT169N
https://www.busybeetools.com/content/product_manuals/CT169N.pdf

Page 12 of that manual shows this:



and this:



So it appears that even with that cover removed you will not have a piece of sanding belt with a support platten behind it but with access to the edge of the belt.



HBilly1022 said:


> Not sure 28" is a good size to get now.



Yeah, I think you're right.....I searched on the Lee Valley tools site (my "goto" site for sanding belts) and they have NONE that size.

-brino


----------



## Ken from ontario

HBilly1022 said:


> Busy Bee is about 5 to 6 hrs drive but there is a similar looking one at Princess Auto which is closer and I will take a close look at it on Monday when I go to the big City. Not sure 28" is a good size to get now. I read some comments on the Busy Bee site that the belts are very hard to find. I did some searching and only came up with 2 suppliers, Busy Bee and Princess Auto. Pretty limited selection too. Might have to consider using my 1" x 30" for now and building a 2" x 42" so I can get a better selection of belts. Great another project to put on the list, lol.


I would try "sandpaper.ca and see if there's a minimum order for 2"x 28" belt size,  they might cut them to size for you as special order .

http://www.sandpaper.ca/product-category/sanding-belts


----------



## HBilly1022

Thanks guys.

I don't want to take this great thread off topic so I may start another thread on this topic after I get a chance to chase up some options.


----------



## mikey

brino said:


> Here's a manual for the Busy Bee 2x28" CT169N
> https://www.busybeetools.com/content/product_manuals/CT169N.pdf
> 
> Page 12 of that manual shows this:
> View attachment 244294
> 
> 
> and this:
> View attachment 244295
> 
> 
> So it appears that even with that cover removed you will not have a piece of sanding belt with a support platten behind it but with access to the edge of the belt.
> 
> 
> 
> Yeah, I think you're right.....I searched on the Lee Valley tools site (my "goto" site for sanding belts) and they have NONE that size.
> 
> -brino



Thanks, Brino. The pics help to show this machine will not work as a tool grinder, at least not for the rake angles. Too bad.

Guys, look for one like Doubleeboy linked to. I know that sander will definitely work. Somebody in Canada must carry one for a not-stupid price.


----------



## Z2V

*I made myself a set of 3/8" tools today to use with the new lathe. I made the threading tool to cut left or right threads. The square tool took a good heavy cut like butter and left a great finish also. 
I took a quick video but I can't insert it for some reason.
I'm going to like these tools!!*

*We've added a couple more names to the list today!! I think we have 23 signed up so far. Keep em coming.*

We still have a set in Canada also.


----------



## mikey

Z2V said:


> View attachment 244413
> View attachment 244414
> View attachment 244415
> 
> *I made myself a set of 3/8" tools today to use with the new lathe. I made the threading tool to cut left or right threads. The square tool took a good heavy cut like butter and left a great finish also.
> I took a quick video but I can't insert it for some reason.
> I'm going to like these tools!!*
> 
> *We've added a couple more names to the list today!! I think we have 23 signed up so far. Keep em coming.*
> 
> We still have a set in Canada also.



New lathe, new skills, new tools - you're doing great, Jeff. Seeing you, Barry, Dave, Bamban and the others succeed has made me so happy. You guys have made all the work worthwhile - thank you all!


----------



## ddickey

https://trugrit.com/index.php?main_page=index&cPath=1_145_149&zenid=da61a8494e0c754d0d4989c0051d0d3a
Plenty here.


----------



## HBilly1022

ddickey said:


> https://trugrit.com/index.php?main_page=index&cPath=1_145_149&zenid=da61a8494e0c754d0d4989c0051d0d3a
> Plenty here.



Even these guys don't carry 2" x 28"!!!!! Must be a real oddball size. I'll pass on that size sander just for that reason.

Z2V, Those are nice looking grinds and I see you did double duty on the threading tool. Did you also grind both ends of the other 2?

I was in the City yesterday and picked up 5 - 3/8" HSS blanks, to try may hand at grinding using the info provided by Mike. Also picked up some 1" x 30" belts and gave that a go but the AO belts took too long to grind using a 50 grit, which was the coarsest I could find and AO was the only thing available. Used the grinder to bulk off material and then back to the belt sander for find tuning and then a new diamond hone. I need to work on my honing skills but the tool cut great. Took a 0.100" DOC on some mystery steel and the material just peeled off. Didn't even get real hot either. That is the biggest DOC I have ever taken. I like this. THANK YOU MIKE.

I'm not sure how to judge the radius on the cutting edge of the tool and I'm looking forward to seeing the sample tools Mike has in distribution so I get get that right, along with the other grinds.


----------



## mikey

HBilly1022 said:


> Even these guys don't carry 2" x 28"!!!!! Must be a real oddball size. I'll pass on that size sander just for that reason.
> 
> Z2V, Those are nice looking grinds and I see you did double duty on the threading tool. Did you also grind both ends of the other 2?
> 
> I was in the City yesterday and picked up 5 - 3/8" HSS blanks, to try may hand at grinding using the info provided by Mike. Also picked up some 1" x 30" belts and gave that a go but the AO belts took too long to grind using a 50 grit, which was the coarsest I could find and AO was the only thing available. Used the grinder to bulk off material and then back to the belt sander for find tuning and then a new diamond hone. I need to work on my honing skills but the tool cut great. Took a 0.100" DOC on some mystery steel and the material just peeled off. Didn't even get real hot either. That is the biggest DOC I have ever taken. I like this. THANK YOU MIKE.
> 
> I'm not sure how to judge the radius on the cutting edge of the tool and I'm looking forward to seeing the sample tools Mike has in distribution so I get get that right, along with the other grinds.



Glad the geometry worked for you, HB. Now that you can take a big cut, see how the tool works for small cuts; this is where HSS really shines. 

Pick a material and take a skim cut to get the skin off and then measure it. Choose a target size, with dimensions in the tenths. Rough it with the tool perpendicular to the work until you're within 0.01000" of final size. Then turn the tip of the tool toward the tailstock about 10 degrees and take 0.005 - 0.007" off with a sizing pass. Without changing the tool angle, take one or two finish cuts and see if you can come in exactly on size. This is how you will normally work with your tool - rough ugly, size to get close and then shave off a hair to come in on size. 

This brings to mind the concept of tolerances. In a production shop, tolerances usually run +/- 0.005" unless otherwise stated. In a hobby shop, a guy with a good tool can get his range much tighter without too much trouble once he knows how the tool likes to cut. I have a square tool that is well over a decade old. It is in need of regrinding or replacement but I am loathe to get rid of it because it will cut whatever I can dial in. If I dial in a depth of cut with a dial indicator the tool will usually cut it. This tool has cut off 0.0002" off the diameter in a controlled cut. Everything is right on this tool, especially the nose radius, so I gently hone only the top when it needs to be sharpened. My daily driver knife tool will do the same thing.

As for nose radius, my suggestion is to buy a radius gauge set. A cheap import set will do. This allows you to have a clear idea of what a 1/64" or a 1/32" radius looks like. You do not need to be exact with your nose radius; just get it close. When you stone it onto the tip of the tool, grind a flat slightly less than the desired nose radius and be sure the flat is even from the top to the bottom of the tool, then gently round the edges of the flat to blend in with the side and end faces.


----------



## HBilly1022

mikey said:


> Glad the geometry worked for you, HB. Now that you can take a big cut, see how the tool works for small cuts; this is where HSS really shines.
> 
> Pick a material and take a skim cut to get the skin off and then measure it. Choose a target size, with dimensions in the tenths. Rough it with the tool perpendicular to the work until you're within 0.01000" of final size. Then turn the tip of the tool toward the tailstock about 10 degrees and take 0.005 - 0.007" off with a sizing pass. Without changing the tool angle, take one or two finish cuts and see if you can come in exactly on size. This is how you will normally work with your tool - rough ugly, size to get close and then shave off a hair to come in on size.
> 
> This brings to mind the concept of tolerances. In a production shop, tolerances usually run +/- 0.005" unless otherwise stated. In a hobby shop, a guy with a good tool can get his range much tighter without too much trouble once he knows how the tool likes to cut. I have a square tool that is well over a decade old. It is in need of regrinding or replacement but I am loathe to get rid of it because it will cut whatever I can dial in. If I dial in a depth of cut with a dial indicator the tool will usually cut it. This tool has cut off 0.0002" off the diameter in a controlled cut. Everything is right on this tool, especially the nose radius, so I gently hone only the top when it needs to be sharpened. My daily driver knife tool will do the same thing.
> 
> As for nose radius, my suggestion is to buy a radius gauge set. A cheap import set will do. This allows you to have a clear idea of what a 1/64" or a 1/32" radius looks like. You do not need to be exact with your nose radius; just get it close. When you stone it onto the tip of the tool, grind a flat slightly less than the desired nose radius and be sure the flat is even from the top to the bottom of the tool, then gently round the edges of the flat to blend in with the side and end faces.



Thanks Mike, I learned something new again. I wasn't aware of the proper sequence for getting to target diameter. Going to give that a go later. I've just been leaving the tool at the same angle and trying to hit target size that way but sometimes (well really, a lot of times) the finish is not good and I have to take a lot of small cuts in order not to overshoot the target.

Also wasn't aware of a radius gauge and will now get some of those.


----------



## mikey

HBilly1022 said:


> Thanks Mike, I learned something new again. I wasn't aware of the proper sequence for getting to target diameter. Going to give that a go later. I've just been leaving the tool at the same angle and trying to hit target size that way but sometimes (well really, a lot of times) the finish is not good and I have to take a lot of small cuts in order not to overshoot the target.
> 
> Also wasn't aware of a radius gauge and will now get some of those.



You have a tool that will do what you tell it to but you have to use it correctly. Don't worry; we all have to learn to stage our cuts at some point. Your tool will make very shallow cuts with just the nose radius as you've been doing but it will finish better when the lead angle/side cutting edge is turned toward the tailstock. Since you have more of the side cutting edge in contact with the work cutting forces will be higher but we are taking small cuts so its not usually an issue. The important thing is to come in on size with a decent finish. Give it a try. You will need to play with your angle until it cuts clean and finishes nicely. Eventually, you learn to position the tool at a glance; I do it without even thinking about it.

As for the radius gauges, spending your money is what we do!


----------



## Z2V

HBilly
I only ground both ends of the threading tool. I biased the cutting tip to the left side of the tool on one end and the right side on the other end. 
You mentioned honing, I honed four 3/8" tools last night and my fingers are killing me, LOL

Hey Mikey, This is a great forum and one outstanding thread, Thank You Sir


----------



## mikey

Z2V said:


> Hey Mikey, this is a great forum and one outstanding thread, Thank You Sir



You're welcome, Jeff. The guys on the HM forum are best - they make newbies feel welcome and comfortable asking questions. Heck, they even let me on here.


----------



## Fallriverbryan

I think a person could make the radius gauge pretty simply at home. Take a 2 x 2 piece of sheet metal and drill holes in each of the corners.
Drill an 1/8 inch hole for a 1/16th radius, a 1/16 hole for 1/32 radius, then grind the corner off, exposing the radius gauge.


----------



## mikey

@HBilly1022, @DHarris, I just checked on Amazon and they sell a pack of 1X30 belts with an assortment of grits. I bet this would make your belt sanders much better for tool grinding. Here is the link: https://www.amazon.com/Makers-Premi...=1508298760&sr=1-4&keywords=1x30+ceramic+belt


----------



## HBilly1022

Fallriverbryan said:


> I think a person could make the radius gauge pretty simply at home. Take a 2 x 2 piece of sheet metal and drill holes in each of the corners.
> Drill an 1/8 inch hole for a 1/16th radius, a 1/16 hole for 1/32 radius, then grind the corner off, exposing the radius gauge.



GREAT idea, especially since I only plan to use it for tool grinding. Thanks for the tip.


----------



## HBilly1022

mikey said:


> @HBilly1022, @DHarris, I just checked on Amazon and they sell a pack of 1X30 belts with an assortment of grits. I bet this would make your belt sanders much better for tool grinding. Here is the link: https://www.amazon.com/Makers-Premi...=1508298760&sr=1-4&keywords=1x30+ceramic+belt



Thanks for the link Mike. Unfortunately they do not ship that item to Canada. I'm pretty sure I can find 1" x 30" ceramic belts somewhere up here but I've been busy in the shop for the last few days so internet hunting is on hold for a bit.


----------



## mikey

HBilly1022 said:


> Thanks for the link Mike. Unfortunately they do not ship that item to Canada. I'm pretty sure I can find 1" x 30" ceramic belts somewhere up here but I've been busy in the shop for the last few days so internet hunting is on hold for a bit.



Amazon.Ca has them: https://www.amazon.ca/Knife-Makers-...sr=1-7-spons&keywords=1x30+ceramic+belt&psc=1


----------



## Aukai

I have ordered this 2x42 in 60, and 120, It can be returned if it's the wrong one.

https://www.amazon.com/gp/product/B00H8YWKJ0/ref=oh_aui_detailpage_o02_s00?ie


----------



## ddickey

Where are these belts made? I don't see them on Trugrit.com.
What is the difference between these two packages?
https://www.amazon.com/Makers-Premium-Ceramic-Sanding-Assortment/dp/B06W2KSFJ1?ref=ast_p_pg_ma&th=1

https://www.amazon.com/Makers-Premium-Ceramic-Sanding-Assortment/dp/B01N8RM0OT?ref=ast_p_pg_ma


----------



## mikey

Aukai said:


> I have ordered this 2x42 in 60, and 120, It can be returned if it's the wrong one.
> 
> https://www.amazon.com/gp/product/B00H8YWKJ0/ref=oh_aui_detailpage_o02_s00?ie



Aukai, do you have a belt sander? If so, the 60 grit will work. I used the 36 grit to shape and the 80 grit to finish. The 36 grit cuts fast! I think the 60 grit will work, albeit slower.


----------



## mikey

ddickey said:


> Where are these belts made? I don't see them on Trugrit.com.
> What is the difference between these two packages?
> https://www.amazon.com/Makers-Premium-Ceramic-Sanding-Assortment/dp/B06W2KSFJ1?ref=ast_p_pg_ma&th=1
> 
> https://www.amazon.com/Makers-Premium-Ceramic-Sanding-Assortment/dp/B01N8RM0OT?ref=ast_p_pg_ma



Belts made by Hermes, a German maker, and assembled and sold by Red Label. 

The difference between the two packages on Amazon is that the cheaper one is shipped by Amazon; the other is drop shipped from Red Label.

I don't know how good other ceramic belts work but I do know the Hermes belts work really well. I'm sold anyway.


----------



## ddickey

Thanks Mike.
Noticed the one package had a light weight backing on the finer grits also.
Just ordered.


----------



## HBilly1022

mikey said:


> Amazon.Ca has them: https://www.amazon.ca/Knife-Makers-...sr=1-7-spons&keywords=1x30+ceramic+belt&psc=1



Thanks Mike. They've been ordered.


----------



## mikey

mikey said:


> Aukai, do you have a belt sander? If so, the 60 grit will work. I used the 36 grit to shape and the 80 grit to finish. The 36 grit cuts fast! I think the 60 grit will work, albeit slower.



@Aukai, my apologies but it might be better to get the assortment to try first: https://www.amazon.com/Makers-Premi...8&qid=1508347062&sr=8-1&keywords=2x42+ceramic


----------



## Metal

Whoops I totally forgot about this

Mikey: can you shoot me your mailing address, I'd like to shoot out the 3dp example tools to you to see if you think anything should be added or any lightbulbs go off before I make any for anyone


----------



## mikey

Metal said:


> Whoops I totally forgot about this
> 
> Mikey: can you shoot me your mailing address, I'd like to shoot out the 3dp example tools to you to see if you think anything should be added or any lightbulbs go off before I make any for anyone



I'll PM it to you. Thank you, Sir!


----------



## Ken from ontario

Mike I just sent you a PM.


----------



## tweinke

If the printed tools look like a good deal for me at least I think owning a set would be nice for future reference and to possibly help someone out if I can.


----------



## tweinke

Oh by the way, previously I had read Mikey's tool grinding technique article elsewhere and gave an attempt at grinding his way sometime ago. They were the first tools that convinced me that HSS was the way to go on my machine and after getting the models and regrinding to match they work even better. Took the models for me to get angle and radius right. Now I want to build a 2x72 belt grinder when I have a chance.


----------



## Aukai

Mike, thank you. I just added the 36 grit, and see how that goes.


----------



## mikey

tweinke said:


> Now I want to build a 2x72 belt grinder when I have a chance.



Yeah, me, too! You guys are going to leave me in the dust very soon, Todd.


----------



## HBilly1022

Mike, I tried the cutting method you suggested and ended up on the money (well according to my calipers it was within 0.0005"). Probably just a lucky run, never to be duplicated again, lol. It sure is a pleasure using a really sharp tool. It even left a pretty good finish on the mild steel rod I used for a test run.

Here's a couple of pics of the cutting tool for your critique.


----------



## mikey

HBilly1022 said:


> Mike, I tried the cutting method you suggested and ended up on the money (well according to my calipers it was within 0.0005"). Probably just a lucky run, never to be duplicated again, lol. It sure is a pleasure using a really sharp tool. It even left a pretty good finish on the mild steel rod I used for a test run.
> 
> Here's a couple of pics of the cutting tool for your critique.
> View attachment 244621
> 
> 
> View attachment 244622



That's a fine looking tool, HB. You got all the angles right and the nose radius looks good. I can tell your platen is bending but that isn't causing an issue with your tool - came out really nice!! I would be proud to use that tool. 

You will find that a square tool will do most things well and now that you have one that works for you, try learning to grind and use a knife tool. Grind one and get it sharp, then try cutting a shoulder a precise distance from the end of the work. There will be times when this is important. Also try turning a piece of brass down to 0.0500" X 0.75" long and use the knife tool to bring it in on size without a taper. Not all tools can do this but a knife tool can.

I'd say you're well on your way, HB - good for you!

Oh yeah, did your hands cramp up after honing like Jeff and me? I hate that ...


----------



## HBilly1022

Thanks for the encouragement Mike. I'll make a knife tool in a few days when I get a chance to go back to the shop.

No my hands didn't get sore so I must not have spent enough time at it. Looking at your pics again I see your finish is a lot finer than mine. I might have to give it another go but I'm pretty happy with the way it cuts now. With a little more honing effort will the cut improve or will it remain sharp longer?


----------



## mikey

HBilly1022 said:


> With a little more honing effort will the cut improve or will it remain sharp longer?



Both. Honing well removes most of the sawtooth defects at the cutting edge. This translates into a longer lasting sharp edge and better finishes. It takes me twice as long (or more) to hone as it does to grind a tool.


----------



## HBilly1022

mikey said:


> Both. Honing well removes most of the sawtooth defects at the cutting edge. This translates into a longer lasting sharp edge and better finishes. It takes me twice as long (or more) to hone as it does to grind a tool.



That explains why my hands didn't get sore. I spent no more than a couple of minutes honing. I thought it was just to get rid of the burrs.


----------



## Z2V

Mike, are you using wax on your ceramic belts as you did with the AO belts?


----------



## mikey

Z2V said:


> Mike, are you using wax on your ceramic belts as you did with the AO belts?



Yup, I am. I'm not sure if the wax helped but the ceramic belt cut really cool and really fast. I'll continue to use it.


----------



## mikey

HBilly1022 said:


> That explains why my hands didn't get sore. I spent no more than a couple of minutes honing. I thought it was just to get rid of the burrs.



Just get rid of all the grind marks and make sure there is no light reflecting off the side and end edges. Sore hands are optional.


----------



## Aukai

Cramps = hydration while working hard. Now.... WAX??? paraffin, or bees?


----------



## mikey

Cramps can also be due to overuse or prolonged tension in muscles that are un-used to being abused by a hobby guy with coarse grind marks on his stupid tool.  

Wax = stick wax lubricant, like this: https://www.amazon.com/Castrol-Stick-Wax-Metal-Working-Lubricant/dp/B00H9P0T0U. One tube will last you maybe 10 years or so. You just touch it to the running belt for maybe a few seconds and it reduces the grinding temperature and friction significantly.

EDIT: stick wax is a great lube for bandsaw blades and hacksaws. Cuts much faster, easier and no mess from coolant systems. Works for drilling, tapping, too. Might even work for diaper rash but not sure about that.


----------



## Z2V

I've used the tube wax for drilling and tapping for many years but never for grinding, makes since though.

Now that I have a lathe again I can soon get back to the belt grinder project, I need to turn the wheels. Yea, I know I can buy them but that's no fun!!


----------



## Aukai

Humph, can't be delivered to my address.....


----------



## mikey

Aukai said:


> Humph, can't be delivered to my address.....



This one will: https://www.amazon.com/C-R-Laurence...coding=UTF8&psc=1&refRID=ZYJ9GKCSAPPGCT5KPCJF

They're all pretty much the same.


----------



## HBilly1022

I'm going to try using my WorkSharp sander for honing. It does an awesome job on knives so I'm thinking it will on the tool too. I'll let you know after I get a chance to try it. May be a side benefit too ........ no cramped hands.


----------



## Aukai

That one works Mike. Thank you.


----------



## Sackett

This is prrobably the "GREATEST" thread on Hobby Machinists ever! I tried to grind a tool as Mike described in an earlier thread,,n it did cut better than any I had ground before,,,but still not quite right. Got key stock today, n not very patiently waiting my turn with models. Hope to get a glass platen, n some decent belts for my Horrible Fright sander before they get here


----------



## mikey

Sackett said:


> This is prrobably the "GREATEST" thread on Hobby Machinists ever! I tried to grind a tool as Mike described in an earlier thread,,n it did cut better than any I had ground before,,,but still not quite right. Got key stock today, n not very patiently waiting my turn with models. Hope to get a glass platen, n some decent belts for my Horrible Fright sander before they get here



Thank you, Sackett! Now I'll be waiting to see how your tools turned out so please share them with us and join the fun. If I can clarify anything, please let me know.


----------



## mikey

Bonehead was over again last night - he wanted to catch up on this thread. He was happy to see that some of you have been making progress but he wanted to make a point. He says, "*... the real point of altering the geometry of a tool to reduce cutting forces is not so much to enable deep cuts; it is to improve accuracy in small cuts. And it doesn't matter if the lathe is big or small.*" 

I told him I already said that but he told me, "Yeah, but you took too many words to say it, and its spread out all over the place." Bonehead is right. A modified tool will allow a smaller lathe to take bigger cuts than it could with a conventional tool or inserted carbide tool but it is in the sizing and finishing cuts that you will see the real effect of a good tool. It will cut more accurately.

Bonehead says, "*Rough ugly, size to get close and then micro-cut to come in on size.*"

So, I told him to write the article himself and he smiled and said, "Yeah, but I no can type!" :mooning:


----------



## ttabbal

Bonehead sounds like my kind of a-hole.

Looks like it's almost my turn to attempt grinding my fingers off! 

What size keystock are the originals? I don't have a lathe yet, so I'm just going to copy them in the original format for now.


----------



## mikey

ttabbal said:


> Bonehead sounds like my kind of a-hole.
> 
> Looks like it's almost my turn to attempt grinding my fingers off!
> 
> What size keystock are the originals? I don't have a lathe yet, so I'm just going to copy them in the original format for now.



I'll pass on your comments to Bonehead; he'll like that. 

Originals are 3/8" keystock.


----------



## thomas s

Thank you Mikey, I made a set of tools from your samples and they work great on my 12X36 Atlas/Craftsman lathe. I have had this lathe for thirty years I can hear and feel how much better these cut. A thank you to Jeff also for doing the mailing list. Thomas S.


----------



## Aukai

thomas s said:


> Thank you Mikey, I made a set of tools from your samples and they work great on my 12X36 Atlas/Craftsman lathe. I have had this lathe for thirty years I can hear and feel how much better these cut. A thank you to Jeff also for doing the mailing list. Thomas S.



That is a real testament.


----------



## mikey

thomas s said:


> Thank you Mikey, I made a set of tools from your samples and they work great on my 12X36 Atlas/Craftsman lathe. I have had this lathe for thirty years I can hear and feel how much better these cut. A thank you to Jeff also for doing the mailing list. Thomas S.



You're welcome, Tom. I appreciate the feedback and I hope they work as well for you as they do for me. The fact that you had an open mind and tried these tools says a lot about you!

And yes, Jeff has been a major help. Thanks, Jeff!


----------



## Z2V

Thanks guys, I'm glad to be able to pitch in.


----------



## HBilly1022

Well I tried the Worksharp for honing. It took a long time to get rid of the grind marks but the finish was like a mirror. I couldn't do the top of the tool on the Worksharp and did that by hand. I used the tool for a bit and noticed the cut was changing (getting dull). Could see a dull spot near the tip of the radius. So I decided to try honing on the little belt sander using progressively finer paper. Went up to 320 and got a very nice finish in less time.

This tool cuts very nicely and leaves a great finish. The HSS I am using must be poor quality though because the edge dulls quite easily and needs to be honed often. Where do you source quality HSS? I looked at q20v's post and noticed that with a grinder there is a hollow left in the middle of the faces, which results in only having to hone the top and bottom edges of the faces instead of the whole face. I think this would reduce the honing time significantly, unless I'm missing something.

I have a question about the feed rate? As you suggested I tried different feed rates with small DOC's and noticed I had to go very slowly in order to get small chips. If I went faster I would get long curling threads of mild steel. Is that ok for roughing cuts? I'm not sure what a chip should look like. What should I be looking for?


----------



## mikey

HBilly1022 said:


> Well I tried the Worksharp for honing. It took a long time to get rid of the grind marks but the finish was like a mirror. I couldn't do the top of the tool on the Worksharp and did that by hand. I used the tool for a bit and noticed the cut was changing (getting dull). Could see a dull spot near the tip of the radius. So I decided to try honing on the little belt sander using progressively finer paper. Went up to 320 and got a very nice finish in less time.
> 
> This tool cuts very nicely and leaves a great finish. The HSS I am using must be poor quality though because the edge dulls quite easily and needs to be honed often. Where do you source quality HSS? I looked at q20v's post and noticed that with a grinder there is a hollow left in the middle of the faces, which results in only having to hone the top and bottom edges of the faces instead of the whole face. I think this would reduce the honing time significantly, unless I'm missing something.
> 
> I have a question about the feed rate? As you suggested I tried different feed rates with small DOC's and noticed I had to go very slowly in order to get small chips. If I went faster I would get long curling threads of mild steel. Is that ok for roughing cuts? I'm not sure what a chip should look like. What should I be looking for?



Let me handle the tool-related stuff first. 

The fastest way to a mirror finish is with belts. Jump up through the grits as you did to get rid of grind marks while maintaining your geometry. If you want to do very little honing, go up to 600 and you only need to do very light honing.
If the tool is dulling quickly I would suspect it wasn't quite sharp to being with. When honing, sight along the cutting edges. When the edge is sharp it will look like a sharp line. If the edge is not sharp you will see light reflecting off that edge. Your goal is to remove that reflection. When sharp, a HSS tool can cut a LOT of material before it needs to be touched up. Don't rely on your thumb to tell you if its sharp; use your eyes.
The choice between a bench grinder or belt sander is yours. It will come down to what you are most comfortable working with because both work. For me, the sander is much faster and more accurate, and changing grits takes seconds; not so on a bench grinder. Try stepping up through the grits and see.
The best and cheapest source for HSS bits will be ebay. You have to be patient and you need to know what you want. I would buy some Chinese import bits to play with and experiment with but once I found a geometry I liked, I would grind it from a good quality blank. See my End Notes post in this thread for suggestions. For now, stay with M2 or T1 HSS. Watch for auctions with new blanks; I do not buy used tools. If you're patient, deals come up. I just bought 8 new USA-made Mo-Max M2 bits for 40 bucks, which is more than I usually pay. A few days later, I bought 11 new DoAll T1 bits for $15.00. Not too long ago I got a box of 20 ETM M2 bits for $20.00. You have to watch, wait and then jump when you see what you want at a price you can handle. If you have the money you can still buy most quality tool bits from Industrial supply houses but it will cost you. Better to buy Chinese bits and use them while you're looking for a deal on ebay.
Chip formation is a function of depth of cut, feed rate, tool geometry and the properties of the material being turned. Many materials, including some mild steels, stainless steel and aluminum will produce long, stringy chips that can reach many feet long. These chips are sharp and dangerous; do NOT grab them with your hands and do NOT go near them with the lathe running. A long chip will often rapidly wrap around the work and can easily drag your hand into the chuck if you get close. If they wrap around the work or chuck, STOP the lathe and remove them with pliers.

You can avoid long, stringy chips in most materials by taking a decent depth of cut and increasing your feed rate when roughing. When roughing, you do not care about finish; you are trying to remove material in the least amount of time. For example, if you wanted a 0.500" OD final diameter but only had a 0.75" piece of 12L14, you can take a 0.100" deep roughing cut at a feed rate that produced chips. 12L14 usually produces stringy chips but it will come off as small chips if your DOC and feed rate are fast enough. The same is true for stainless and aluminum. I cannot give you numbers for these things because each lathe is different. The best way to find out is to burn some material and experiment. 

When taking sizing and finishing cuts, you will be taking smaller DOC and your feed rate will be slower so you'll produce stringier chips at times. You learn to live with that but you can minimize them by altering your lead angle. You have to try different speeds, feeds, DOC and lead angle to figure out what works for you. I know this sounds like a lot of work but that is what you're trying to learn. Turning stuff is knowing about your materials and how it likes to be cut. Having a good tool makes things much easier and oftentimes a geometry made to work with a given material is the way to go. Remember that the square tool works well in most stuff but a tool ground to work with a specific material group will always be better. This is why I spent so much time going over tool angle modification.

The bottom line is that you need to buy some stock and spend some time messing around with your *cutting conditions* (DOC, speed, feed) to learn how your lathe and tools work with different materials. In general, rough at higher feed rates and finish at lower feed rates. Rough with the tool perpendicular to the work or maybe slightly toward the chuck; finish with the tool turned slightly toward the tailstock. And so on ...

These things take time. Having a good tool helps more than you know.


----------



## mikey

I should add to the above that the right feed isn't always going to be available on your lathe; depends on the gearing. Quite often, I will just feed manually when roughing to get the chips to come off the way I want. I may set the rpm for the material but I will feed manually to get chips instead of stringers. This is especially true of aluminum, which forms long stringers. When roughing, I may run my lathe at about 1100 rpm and hand turn the feed; with enough DOC and a fast enough feed the chips come off as chips, not stringers. Of course, this is with a tool modified to work with aluminum. Similarly, stainless steel likes to come off as looong stringers. My stainless tool has a lot of side rake and even with a moderate DOC, the chips come off as short curled chips, not stringers. This has more to do with geometry than anything else so, again, learn to modify your tools to work the way you want them to.

There is a lot to learn about turning but be patient and experiment with it; it will come.


----------



## Bamban

Mikey,

You are so right about knowing your material and your lathe. I have some occassions, same material barrels from the same company don't always cut the same. For example, on same SFM, doc, and feed, one will string and the next one chips in 2 to 3 inch long when roughing. 

I always make a short test cut, just to figure out what I am up against.

I am so afraid of those long razor sharp continuous strings, With a swarf tool I tried to break them at foot long and kind of swing them to the left of the operator to be collected on the floor.

Nez


----------



## HBilly1022

Thanks so much for your response Mike. I really appreciate the time, effort and knowledge you have put into this thread and with guiding me. I've only been at this hobby machining for a couple of years, on a part time basis and it seems like the more I learn, the more I discover how little I know. I've struggled with finishes and getting to target depth for quite a while. Sometimes it seems to come together but I don't know why and most times I just accept the less than great finish and the close enough size. I have found that with this grind I get a far superior finish and it is waaaay easier to hit the target size. Also, very importantly, it is consistent, even for me. The only way I could get a decent finish with mild steel before was to use a shear tool with a very small DOC (0.001" or 0.002") and the slowest feed rate. Now I get better finishes consistently and I don't have to sneak up on the final size with a bunch of very small shear cuts.

I'm glad to hear the long strings are normal and will not concern myself with that when taking roughing cuts.

I'll take a closer look at my honing, especially the top surface, as that is where I think I may not be getting the finish right.


----------



## mikey

Bamban said:


> Mikey,
> 
> You are so right about knowing your material and your lathe. I have some occassions, same material barrels from the same company don't always cut the same. For example, on same SFM, doc, and feed, one will string and the next one chips in 2 to 3 inch long when roughing.
> 
> I always make a short test cut, just to figure out what I am up against.
> 
> I am so afraid of those long razor sharp continuous strings, With a swarf tool I tried to break them at foot long and kind of swing them to the left of the operator to be collected on the floor.
> 
> Nez



Yeah, you have to know your materials. That's where the pro guys have a lot more experience than us hobby guys because they work with bigger batches. Still, we can learn if we are willing to experiment. 

I agree that some lots of the same material will cut differently and I'm not sure how to explain it. I know that with stainless, if I get the side and back rake correct I can avoid stringers to a much finer degree. Your Rex AAA tool does a good job of chip flow, right?

Like you, I am very careful around long stringers. You will find that if you manually feed, a very short pause in feed will break those stringers off. If you haven't done so, give it a try. Be safe, Nez.


----------



## mikey

HBilly1022 said:


> Thanks so much for your response Mike. I really appreciate the time, effort and knowledge you have put into this thread and with guiding me. I've only been at this hobby machining for a couple of years, on a part time basis and it seems like the more I learn, the more I discover how little I know. I've struggled with finishes and getting to target depth for quite a while. Sometimes it seems to come together but I don't know why and most times I just accept the less than great finish and the close enough size. I have found that with this grind I get a far superior finish and it is waaaay easier to hit the target size. Also, very importantly, it is consistent, even for me. The only way I could get a decent finish with mild steel before was to use a shear tool with a very small DOC (0.001" or 0.002") and the slowest feed rate. Now I get better finishes consistently and I don't have to sneak up on the final size with a bunch of very small shear cuts.
> 
> I'm glad to hear the long strings are normal and will not concern myself with that when taking roughing cuts.
> 
> I'll take a closer look at my honing, especially the top surface, as that is where I think I may not be getting the finish right.



You're welcome, HB.

One key point I was trying to make about stringers is that they are dangerous. They will cut you but more importantly, if they catch your hand or arm and then they wrap around the work then they can pull you into the lathe. If you have a big nest of stringers, stop the lathe and clear them. Please don't get hurt.

I'm glad the tool is making your work easier and more accurate. I've been criticized before about the angles on my tools. Some experienced guys say the angles are too much. I grind them this way because it works better for me - roughs better, sizes easier and finishes far more accurately. In the end, that is what counts.

Yeah, try to hone until there is no light reflecting off your edges. A sharp tool will cut quite a bit of stock before it needs honing. Hang in there, HB; it will come.


----------



## Bamban

Yup, chip flow is great. 

Have to try the pause trick, thanks.


----------



## bfk

mikey said:


> Bonehead was over again last night - he wanted to catch up on this thread. He was happy to see that some of you have been making progress but he wanted to make a point. He says, "*... the real point of altering the geometry of a tool to reduce cutting forces is not so much to enable deep cuts; it is to improve accuracy in small cuts. And it doesn't matter if the lathe is big or small.*"



Your friend Mr Head is dead right. I got a little time yesterday to play with the RH tool, the one I had used to take deep cuts last week. This time I was seeing just how small a cut I could get. I managed to consistently take .001 off the diameter to a piece of 6061, and get a nice finish. Considering this was the first MikeyModel™ tool I had made, I'm very happy. 
One reason I got into this was to learn new things before my brain atrophies, and this whole grinding process has been a great learning experience.
Thanks again.


----------



## mikey

bfk said:


> Your friend Mr Head is dead right. I got a little time yesterday to play with the RH tool, the one I had used to take deep cuts last week. This time I was seeing just how small a cut I could get. I managed to consistently take .001 off the diameter to a piece of 6061, and get a nice finish. Considering this was the first MikeyModel™ tool I had made, I'm very happy.
> One reason I got into this was to learn new things before my brain atrophies, and this whole grinding process has been a great learning experience.
> Thanks again.



Like your trademarked name there, bfk!  

Yeah, Bonehead is right but I don't want to swell his head with praise - he is already insufferable. Nah, just joking. I will pass along your comments and I'm sure he will happy to hear it. I think its great that you can grind a tool that lets you enjoy your lathe, bfk. Good for you!


----------



## mikey

Guys, I meant to tell you but kept forgetting. When you make a turning pass with your tool it is common for guys to just reverse the saddle feed wheel with the tool still in contact with the work to get the tool clear and then dial in a cut for the next pass. Personally, I don't do this because *I feel it dulls the tool to drag the tip in reverse*. I back up the cross slide a bit to clear the tool of the work and then re-position the saddle before dialing in the next depth of cut. 

If you use carbide inserts the same thing applies. Drag an insert out of a cut and it can chip on you.


----------



## HBilly1022

Yesterday I was making a little knurled head bolt to replace the set screw on my lathe saddle adjustment collar (sorry didn't get pics) and found the need for a left hand tool but didn't have any except for some of those cheap indexable carbides I got a long time ago. I had to cut the shaft to 6mm diameter and tried the carbide but it left a terrible finish and I was afraid to take too much DOC for fear of breaking the shaft off. So I turned one of your LH cutting tools. Wow, what a difference. I could easily take cuts without fear of breaking the shaft. It was slicing through the steel cleanly and left a great finish. Oh ya, I also got to target size with no difficulty. 

Loving these new tools. Thanks Mike.


----------



## mikey

HBilly1022 said:


> Yesterday I was making a little knurled head bolt to replace the set screw on my lathe saddle adjustment collar (sorry didn't get pics) and found the need for a left hand tool but didn't have any except for some of those cheap indexable carbides I got a long time ago. I had to cut the shaft to 6mm diameter and tried the carbide but it left a terrible finish and I was afraid to take too much DOC for fear of breaking the shaft off. So I turned one of your LH cutting tools. Wow, what a difference. I could easily take cuts without fear of breaking the shaft. It was slicing through the steel cleanly and left a great finish. Oh ya, I also got to target size with no difficulty.
> 
> Loving these new tools. Thanks Mike.



It's great to hear that you're gaining confidence and experience with your new tools, HB - your experience was a really nice way to start off my day!

There are times when carbide is the best choice, and you might consider buying an SCLCR tool holder and try some CCMT and CCGT inserts; they work much better than the older style triangular inserts. If you do this, go for the smaller nose radius inserts to keep deflection to a minimum. 

There are also times when roughing and sizing with carbide but finishing with HSS is the best approach. I sometimes do this when working with hard materials and need to hold tight tolerances. A carbide insert will not allow micro-cuts but a HSS tool will. It works.

Bottom line: know your materials and know your tools, then use the best tool for the job at hand.

You're doing great, HB!!!


----------



## Metal

@mikey:

As this thread expands can you move your excellent tutorial posts and edit them into the first post?

At 11 pages and no sign of slowing down its going to become a bear to page through this thing to find the meat eventually


----------



## mikey

I don't know - which posts do you guys think are important? I also don't know if the new software will transfer images and stuff so I'll probably need to contact one of the Mods to discuss it. Can you guys make a note of which posts you think should be consolidated and I can try to create a .pdf file and post that; might be easier. There is now a number in the upper right hand corner of each post.


----------



## Z2V

I'm thinking that someone mentioned doing that sometime back. Of course I'd have to read all 11 pages to find the post.
LOL


----------



## mikey

I suspect that the guys who really want this info will read the whole thing, mine it for the stuff that matters to them and then create their own document.


----------



## DHarris

Hey Mikey,
I've cut and pasted all of your tutorials into a MS word doc (text and photos - 23 pages!).  I've just made a pdf of them all and will try to attache it here to this post.

see if this worked!


----------



## DHarris

Ok, I just checked it and it seems to work for me.
Now, if a moderator can figure out how to "stick" it to a start post or someplace else easy to access we are home free!


----------



## mikey

DHarris said:


> Ok, I just checked it and it seems to work for me.
> Now, if a moderator can figure out how to "stick" it to a start post or someplace else easy to access we are home free!



Thanks, Dave - that saved some work. You weren't kidding; 23 pages!


----------



## DHarris

I have the MS word document that I can e-mail to anyone who wants it in case you want to add your own inputs / references for one package (can't attach it to a post - says not allowed file type?).

Dave

p.s.  Glad to help in some small way Mikey!


----------



## mikey

You did help, Dave - thank you!

I was just thinking - if Bonehead wrote this, it would be maybe 2 pages and by the time you were done reading it you would know more but you would have a headache and also be ****** off!


----------



## cascao

Make sure there are a shear tool included in the models.


----------



## Aukai

I have been printing the pages as we go, and have a folder.


----------



## mikey

I've never used a shear tool, mostly because I never felt the need for one. My tools finish well enough for me.

If you and anyone else would like to make a model or discuss grinding one, please feel free.


----------



## brino

okay I wanted to play too!

I have always used a bench grinder to shape and sharpen my lathe tools in the past.
But I wanted to try this MikeyModel™ too.

The problem was my current bench sander would not allow access to the edge of the belt.
I fixed that here:
http://www.hobby-machinist.com/thre...-sander-to-access-the-edge-of-the-belt.63436/

and then proceeded to create this tool following @mikey's instructions:



the end:



the side:



the top:



I still need to hone it and try it.

-brino


----------



## mikey

Wow, that came out really nice, Brino! Geometry looks good and the finish is really nice, with no heat-related color changes. It looks like your very cool sander mod worked well because the rake angles came out great. 

How do you like grinding tools on the belt sander vs the bench grinder?

Let us know how the tool works for you. I really hope it meets your expectations but if it doesn't then change it until it does.

I have to say that you guys have been grinding some really nice tools, really nice.


----------



## brino

mikey said:


> How do you like grinding tools on the belt sander vs the bench grinder?



You already mentioned one of the biggest differences -HEAT!
The belt sander seems to keep the tool bit cooler. 
I was using a push stick and dipping in water frequently.

I hope to get the honing done and the tool tested one evening this week.

-brino


----------



## thomas s

Nice job Brino


----------



## Dan_S

mikey said:


> If you and anyone else would like to make a model or discuss grinding one, please feel free.



Mr Pete did 2 videos on the sheer tool. I made one and they definitely do an excellent job on soft materials like cooper.


----------



## mikey

I think the shear tool is a good addition to the arsenal because it does produce really nice finishes. I do not know anything about the geometry though, so if you or someone else would like to discuss how to grind one and how the geometry works I think it would be really interesting.


----------



## Doubleeboy

Shear tool, face rake 15 to 20 degree, end clearance rake 7+ degrees.  very easy to grind.  Depth of cut should be limited to a thou or two max.  Works great even with M2 from China.  Machinist workshop did an article by gunsmith editor Steve Acker a few years back, good stuff.


----------



## cascao

Shear tool is good for finish, everybody agree. But it is great too when you need to remove a very small amount of material. Conventional tool sometimes have a grab-no grab behavior.


----------



## mikey

I will need to grind one of these vertical shear tools one day and compare it to my general purpose tool for finish potential and accuracy with small cuts. My oldest square tool will take a tenth depth of cut and produces a really fine finish but that doesn't mean the shear tool can't beat it. We'll see. I'll report it here when I compare the two tools.


----------



## Ken from ontario

mikey said:


> My oldest square tool will take a tenth depth of cut and produces a really fine finish


I affirm that statement to be true, I do have one of Mike's square tool that he personally ground and honed . I know he calls it a "general purpose"tool but IMO it is a perfect tool for dimensioning, when I need  to take off the last few thou, and also to get the best possible finish, this square tool hasn't let me down yet and based on the way I use it , it never will.
It will be a good challenge for you Mike to grind a shear tool that can outperform your square tool but I am looking forward to seeing what you'll come up with.


----------



## Z2V

It will be a good challenge for you Mike to grind a shear tool that can outperform your square tool but I am looking forward to seeing what you'll come up with.[/QUOTE said:
			
		

> No pressure Mike!,


----------



## Dan_S

I thought I would share this bit I finished up last night. I usually use inserts these days, but I broke out this old bit ground for aluminum as I need to turn some nylon this evening.  it has about 10° of front and side clearance, 15° of side rake, and about 35° of back rake. I touched up the old grind on the bench grinder, and then honed it on some cheap diamond hones.


----------



## mikey

A knife tool for aluminum - nice job, Dan. Let us know how it works.


----------



## mikey

Ken from ontario said:


> I affirm that statement to be true, I do have one of Mike's square tool that he personally ground and honed . I know he calls it a "general purpose"tool but IMO it is a perfect tool for dimensioning, when I need  to take off the last few thou, and also to get the best possible finish, this square tool hasn't let me down yet and based on the way I use it , it never will.
> It will be a good challenge for you Mike to grind a shear tool that can outperform your square tool but I am looking forward to seeing what you'll come up with.



Thanks, Ken. You hit on why I don't have a shear tool; I don't feel the need for it. However, until we do a comparison then it is just plain hubris to think that way. First, I need to visualize how the shear tool cuts and see if I can make the best shear tool I can make. Then I'll grind a finishing tool that is purpose ground to compete with it so its at least a fair comparison.

So, guys, why don't we do this. Lets put our heads together and figure out what the ultimate finishing tool would look like - shape, relief and rake angles, nose radius - and see if we can sort out what the tool would look like. Then I'll grind a shear tool and our finishing tool and we'll see which one comes out on top. You guys know enough to figure the geometry out - lets see what you come up with.


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## Dan_S

mikey said:


> A knife tool for aluminum - nice job, Dan. Let us know how it works.


Here you can see the finish in 6061-T6 aluminum and MDS filled nylon. You get long stringy chips because there's no chip breaker however you get the benefit of a really nice finish directly off the tool and very very low tool pressure.


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## mikey

Dan_S said:


> Here you can see the finish in 6061-T6 aluminum and MDS filled nylon. You get long stringy chips because there's no chip breaker however you get the benefit of a really nice finish directly off the tool and very very low tool pressure.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> View attachment 245842



Looks good, Dan!


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## ddickey

Very nice.


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## mikey

Okay, I think I understand how the shear tool works. Basically, you have a cutting edge on an angle that contacts at a tiny point tangent to the outer surface of the work piece. The cutting action is very much like that when cutting with a knife tool that has a small (1/64 - 1/32" across) flat ground at the tip instead of a nose radius; that tool also finishes really nicely. Basically, it slices off a very small shaving. However, because the edge of a shear tool is so long only a small contact point can be allowed if the cutting forces are to be controlled. If your depth of cut is too deep, tangential and radial forces climb rapidly and the tool will chatter and/or the finish will suffer.

I think the angle of the cutting edge would be most efficient when the side face of the tool is kept near vertical. This would minimize the amount of edge in contact with the work so it should reduce tangential forces. I'm thinking of grinding that face at a negative 5 degrees to start with and will increase it (go more negative) and see how that affects depth of cut capability and finish potential. At some point, I should be able to find the optimal angle for the side face. 

Once I find that side angle, I'll focus on the end cutting edge angle and see what is needed to cut clean. I am less concerned about clearance up front. What I want is to lower the radial forces and I think minimizing the amount of horizontal contact the tool has with the work will do it. I know from experience that I need at least 12 degrees of end clearance to cut clean so I'll start there and go up. When edge life falls off, I'll have reached the limit. 

Eventually, we'll have a shear tool that is optimized for both depth of cut and finishing potential. Then we'll grind a finishing tool to see how well it compares to this shear tool. I already know how I would grind it but will wait for input from the group to see what you want to do with it. At the end of this experiment, we should have two tools that should finish well. In terms of utility (facing, turning into shoulders, sizing), the shear tool has already lost that competition.

Okay, I'm comfortable with my plan. I await your input, guys.


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## mikey

Okay, 24 hours and no input so let me start this off and ask questions to stimulate you.

*Shape* - I will use a *finishing tool shape*. Some of you may not have seen this shape before but it has the most lead angle of all turning tools. This is so that when the tool shank is perpendicular to the work, the lead angle is canted significantly toward the tailstock. As we know, shifting the lead angle toward the tailstock increases cutting forces but it also greatly enhances finishes as long as you keep your cuts light. It will also take a fairly healthy cut if the lead angle is reduced by turning the tool and it can cut into a shoulder and size a work piece very well, indeed.
*Relief angles* - _should we stay with a standard relief, increase it or decrease it? What do the relief angles have to do with finish potential? If we were to grind this tool to suit mild steel, what would be an acceptable relief angle?_
*Side rake* - side rake doesn't influence finishes much but it does reduce cutting forces, temperatures and chip flow rates. _Given the changes to the relief angles, would you be conservative or would you increase side rake? If you increase it, why are you doing it?_
*Back rake* - back rake has a significant impact on finishing potential._ Would you increase it? If so, why?_
*Nose radius* - if you ask most machinists about nose radius they will tell you that the bigger the radius, the better the finish. This is true to a degree but a finishing tool actually cuts more with the side cutting edge so the nose radius really doesn't play as big a role as you might think. What a big nose radius does do is deflect and when the tool deflects it doesn't cut. Consequently, cutting forces and cutting temps go up and holding dimensions becomes an issue. Therefore, my suggestion to you as you design tools is to start off with a small nose radius and change it only if it doesn't produce the finish you need. In my experience,*it is always a good idea to know where the tool is cutting and focus the cutting forces there.* _So, here are the questions - if you want to focus the cutting forces in a specific location, what angle do use to do that? How big a radius to we start with?_
As you learn to grind tools, keep in mind that tool geometry is the key to making the tool work the way you want it to. To do that, you need to know what each angle does and how you can change them to suit your needs.  Also remember that in order for a tool to be accurate it must cut, and it must cut where you want it to cut and with the least amount of cutting force you can manage.

Jump in and stick your neck out. Its okay to be wrong; that's how we learn. I promise that no one will laugh at you. Well, at least I won't.


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## Dan_S

In my oinion part of the issue comes down to how you have your lathe set up, and how you prefer to use it. I use a QCTP and it is aligned as close to perfectly square to the spindle as I can get it.  This is so that threading tools don't require any fiddling to get aligned. In general I  just drop the holder on and go, because all my angles are preset by how the tool is mounted in the holder.

In my opinion tool B above is a roughing tool and tool E is a finishing tool.

I call tool B a roughing tool for two reasons. It can't turn to a shoulder and face a shoulder with out being reoriented, and to me that's a no go.  Also because of how the cutting face is oriented to the direction of travel the force vectors want to push the work away from the tool, making it hard to accurately dimension a part.

Tool E is a finishing tool as it can turn to a shoulder and face the shoulder. To be fair the angle of the cutting face means the vector forces want to pulll the work into the tool. However the small positive lead angle, of usually only a degree or two aren't as strong as the negative lead angles on roughing tool that usually set in the 10 to 20 degree range.

I know guys who either don't use A QCTP or have no qualms about reorienting and use nothing more than a tool shaped like A.


In my eyes side rake and back rake depend on the material being cut, so I have different tools for different materials. I've personally found the envelope of acceptable angles to pretty wide so as long as you are in the ballpark of what's quoted in a lot of old texts you are good to go.

With regards to tool bit geometry, tip radius is the most important thing to get correct. The main thing to remember is that you are cutting a fine pitch screw, so the finish is directly related to the tip radius and feed rate. A higher feed means you need a bigger radius to get the same finish  as a smaller radius and a slower feed. Calculators like this one are good tool to help think about it.  http://www.custompartnet.com/calculator/turning-surface-roughness

the other thing to consider is that back and side rake effects the effective tip radius. The more back or side rake you have the bigger the radius needs to be.  This can best be seen by looking at the cross section of a plane and a cylinder at different angles. When cut though at a perpendicular angle the cross section is a circle. At any angle other than a 90 you get an ellipse, and the further than angle is from 90 the more pointy the small end of the ellipse becomes. This image kind of shows it, but its easier to visualize buy just cutting though some round stock at an angle other than perpendicular.



In my opinion honing had the greatest effect on surface finish and cutting performance. It was a night and day difference when I started honing tools many years ago.


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## larry4406

Dan_s

This makes so much sense to a newbie like me:

_"The main thing to remember is that you are cutting a fine pitch screw, so the finish is directly related to the tip radius and feed rate. A higher feed means you need a bigger radius to get the same finish as a smaller radius and a slower feed."_


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## ddickey

Dan_S said:


> Tool E is a finishing tool as it can turn to a shoulder and face the shoulder. To be fair the angle of the cutting face means the vector forces want to pulll the work into the tool. However the small positive lead angle, of usually only a degree or two aren't as strong as the negative lead angles on roughing tool that usually set in the 10 to 20 degree range.


I thought the more negative lead angle the better the resulting finish. That's a question.


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## Dan_S

ddickey said:


> I thought the more negative lead angle the better the resulting finish. That's a question.



In the texts i have read, and based on my own observation it has no real effect on the finish. It does have a chip thinning effect though, that allows you to increase the depth of cut, or the federate, thus allowing you to remove more material.

In my honest opinion unless you are trying to squeeze every last bit of performance out of your machine, just about anything will work. from what i have seen , read, and personally experienced i would prioritize things in this order. 


 Honing the tool bit after grinding.
getting a tool bit radius that coincides with the feed rate you are using, and surface finish you want to achieve. 
get the SFPM into the right ballpark for the material and diameter you are turning.
If you are working with a material that work hardens make sure the depth of cut, feed, and sfpm are correct.

make sure you have enough side and front clearance. 8 degrees works for almost anything. 
get the side and back rake into the ball bark you will find in old texts or online.


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## mikey

Dan_S said:


> View attachment 245921
> 
> 
> In my oinion part of the issue comes down to how you have your lathe set up, and how you prefer to use it. I use a QCTP and it is aligned as close to perfectly square to the spindle as I can get it.  This is so that threading tools don't require any fiddling to get aligned. In general I  just drop the holder on and go, because all my angles are preset by how the tool is mounted in the holder.
> 
> In my opinion tool B above is a roughing tool and tool E is a finishing tool.
> 
> I call tool B a roughing tool for two reasons. It can't turn to a shoulder and face a shoulder with out being reoriented, and to me that's a no go.  Also because of how the cutting face is oriented to the direction of travel the force vectors want to push the work away from the tool, making it hard to accurately dimension a part.
> 
> Tool E is a finishing tool as it can turn to a shoulder and face the shoulder. To be fair the angle of the cutting face means the vector forces want to pulll the work into the tool. However the small positive lead angle, of usually only a degree or two aren't as strong as the negative lead angles on roughing tool that usually set in the 10 to 20 degree range.
> 
> I know guys who either don't use A QCTP or have no qualms about reorienting and use nothing more than a tool shaped like A.
> 
> 
> In my eyes side rake and back rake depend on the material being cut, so I have different tools for different materials. I've personally found the envelope of acceptable angles to pretty wide so as long as you are in the ballpark of what's quoted in a lot of old texts you are good to go.
> 
> With regards to tool bit geometry, tip radius is the most important thing to get correct. The main thing to remember is that you are cutting a fine pitch screw, so the finish is directly related to the tip radius and feed rate. A higher feed means you need a bigger radius to get the same finish  as a smaller radius and a slower feed. Calculators like this one are good tool to help think about it.  http://www.custompartnet.com/calculator/turning-surface-roughness
> 
> the other thing to consider is that back and side rake effects the effective tip radius. The more back or side rake you have the bigger the radius needs to be.  This can best be seen by looking at the cross section of a plane and a cylinder at different angles. When cut though at a perpendicular angle the cross section is a circle. At any angle other than a 90 you get an ellipse, and the further than angle is from 90 the more pointy the small end of the ellipse becomes. This image kind of shows it, but its easier to visualize buy just cutting though some round stock at an angle other than perpendicular.
> 
> 
> 
> 
> 
> 
> In my opinion honing had the greatest effect on surface finish and cutting performance. It was a night and day difference when I started honing tools many years ago.



Dan, I've been pondering the best way to respond to your posts. I want to preface this by saying that I mean no offense but am concerned that some of your statements may be a bit misleading.

Fixing a QCTP is often done by carbide insert users. It allows you to index your tooling and then use the tool with the orientation for which it was designed. This is not how a contemporary HSS tool user generally uses a QCTP. I know that you have stated in the past that you use mainly inserted carbide tooling so it makes sense to use your post this way.

The tool shapes you posted have been around for over a hundred years. All were intended for use in the old-style lantern or 4-way tool posts and were oriented perpendicular to the work. They were all typically ground with the conventional tool angles found in most tool angle tables. Nowadays, we can grind tools to whatever shape we want because the QCTP makes changing lead angles simple, and that greatly expands the capabilities of those tools. Modern hobby guys have moved on with regard to shapes and how the tools are oriented. I, at least, have long since moved on from conventional tool angles as well.

I agree that the rake angles must change for each material; even the tables take this into account but you say the envelope for these angles is pretty wide and I am unclear as to the basis for your statement. What is your understanding about the function of these angles? Even an increase of 2 degrees of side rake can allow a turning tool for stainless steel to produce chips instead of stringers so the envelope is not wide, not really.

With regard to tip or nose radius, you say, "The more back or side rake you have the bigger the radius needs to be." I'm not sure where this came from. It turns out that side rake has little influence on the nose radius. Back rake on the other hand, does. As back rake increases, the cutting forces are focused more and more at the tip of the tool and this greatly aids finishes because the force is focused in a smaller and smaller area as the angle increases. Of interest is that this smaller area is not so much at the nose; it is primarily on the side cutting edge, up near the tip where a properly oriented HSS tool actually finishes. So, the nose radius need not be larger as the rake angles increase; the reality is that the opposite is true. I say this based on years of experience and experimentation, not something I read, and I'm making an issue of it because I don't want the guys to misunderstand something that is very important. Large nose radii on a HSS tool increases radial cutting forces and this leads to more deflection and reduced accuracy. Especially on a finishing tool, it is better to increase back rake and keep the nose radius small. The tool will finish well but it will also be more accurate.

In post 341, @ddickey said, _"I thought the more negative lead angle the better the resulting finish. That's a question."_ Your response was, "In the texts i have read, and based on my own observation it has no real effect on the finish. It does have a chip thinning effect though, that allows you to increase the depth of cut, or the federate, thus allowing you to remove more material."

What you are saying is that increasing the lead angle so that the tool is turned more toward the tailstock does not have a real effect on the finish. This is curious because Machinery's Handbook says otherwise, as does my own experience. This orientation actually brings more of the side cutting edge into contact with the work so cutting forces increase; rather than increase your depth of cut or feed rate as you suggest, you must actually reduce your depth of cut or the tool will chatter. The purpose of turning the tool toward the tailstock is to enhance finishes, and it does. As previously stated, you are finishing primarily with the side cutting edge up near the tip. Furthermore, you may be surprised at how much better some inserts finish when the lead angle is increased; this is not standard practice but it can significantly improve finishes. Ask @Bamban.

In item number 2 of the same post you recommend "getting a tool bit radius that coincides with the feed rate you are using, and surface finish you want to achieve." Are we still talking about HSS tools or does this apply to carbide tools? The nose radius of a carbide insert influences all of your cutting conditions, perhaps more than any other part of the insert's geometry. On a HSS, not so much and definitely not if you alter your lead angles to finish.

In item 4, you said, "make sure you have enough side and front clearance. 8 degrees works for almost anything." In my experience, this is true only if you are grinding tools to conventional angles. If you wish to use tools that do not finish as well and cut with higher cutting forces then this recommendation makes sense. Otherwise, I would have to disagree. Some materials like aluminum and stainless respond really well to increases in the relief angles; typically you have better finishes and reduced work hardening. Brass also likes larger relief angles than a table calls for; the tool will cut more easily, be more accurate and will finish much better. 

In item 5, you said, "get the side and back rake into the ball bark you will find in old texts or online." This might be true if you want a conventional tool. However, if you wish to have a tool that cuts with lower cutting forces, finishes better and dimensions more accurately then no, I disagree. Again, the rake angles are really important, more so than any other tool angle, and this is especially true if the lathe is a smaller one because they have such a huge impact on the cutting forces the tool produces. They also allow us to reduce cutting temperatures enough to reduce work hardening in stainless to a noticeable degree.

I realize that this post may seem to be offensive to you, Dan, but that isn't my intention. You have made statements that you believe to be true and I understand that. I have taken issue only where there is misleading information and have sought to clarify, not argue or denigrate. If you would like to take this further, we can start another thread or take it off line. I understand tip geometry well enough that I can support my position.


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## Dan_S

mikey said:


> Fixing a QCTP is often done by carbide insert users. It allows you to index your tooling and then use the tool with the orientation for which it was designed. This is not how a contemporary HSS tool user generally uses a QCTP. I know that you have stated in the past that you use mainly inserted carbide tooling so it makes sense to use your post this way.


I set up my tooling this way even before I had insert tooling. I've been at it for almost a decade and a half now, and the first 3 or 4 years, all I had was HSS tooling. When I first started out, all I had was a 4 way tool post, and it was a pita to get tools set up as you had the shim tools each time you swapped to a different one.

When I finally got a QCTP, what convinced me to set it and and not change it was when I broke a parting blade. I couldn't afford a lot of tooling at the time, so it was ground out of  1/2" square blank. It took several hours to grind, because it was long, and my grinder was weak. When it broke because the tool post wasn't square enough, a lot of cursing and yelling could be heard in my shop, because not only did i need to regrind a new tool, I had scraped a part that took about 20 hours to make.



mikey said:


> What is your understanding about the function of these angles? Even an increase of 2 degrees of side rake can allow a turning tool for stainless steel to produce chips instead of stringers so the envelope is not wide, not really.


My father started off his career as a tool maker, and when he was visiting one time, he set me strait so to speak. I was trained as a physicist, so I had always been exact with my angles (notes and all). My dad came out to the shop while I was regrinding some tools, and after a few minutes I got the "what are you doing line", because I was setting my tool rest to the proper angles with a protractor/level. I gave him the bit, and he just went at it free hand, not even using the rest, other than to support his hand. he bared down so hard he'd bog the grinder down.

his "words of wisdom" where  something close to just get it close and stop wasting time, if your within a couple of degrees it will work fine. If it doesn't just change the feed rate, depth of  cut or surface footage. My personal experiences since then support this.



mikey said:


> I say this based on years of experience and experimentation, not something I read, and I'm making an issue of it because I don't want the guys to misunderstand something that is very important. Large nose radii on a HSS tool increases radial cutting forces and this leads to more deflection and reduced accuracy. Especially on a finishing tool, it is better to increase back rake and keep the nose radius small. The tool will finish well but it will also be more accurate.


I think you miss understand what I mean by larger. When I say larger I'm meaning give it a few more passes on the hone. In other words the radius will get bigger by a few thousands. 




mikey said:


> What you are saying is that increasing the lead angle so that the tool is turned more toward the tailstock does not have a real effect on the finish. This is curious because Machinery's Handbook says otherwise, as does my own experience. This orientation actually brings more of the side cutting edge into contact with the work so cutting forces increase; rather than increase your depth of cut or feed rate as you suggest, you must actually reduce your depth of cut or the tool will chatter.



We will have to agree to disagree on this point. Machine Shop Practice and my father have both referenced the chip thinning effect. Page 183 in Machine Shop Practice has a diagram explaining this.  It is worth noting, that the power and rigidity of you lathe as well as the rigidity of the work piece must be taken into account.



mikey said:


> In item number 2 of the same post you recommend "getting a tool bit radius that coincides with the feed rate you are using, and surface finish you want to achieve." Are we still talking about HSS tools or does this apply to carbide tools?


It applies to both HSS and carbide tools in my opinion.




mikey said:


> I realize that this post may seem to be offensive to you, Dan, but that isn't my intention. You have made statements that you believe to be true and I understand that. I have taken issue only where there is misleading information and have sought to clarify, not argue or denigrate. *If you would like to take this further, we can start another thread or take it off line.* I understand tip geometry well enough that I can support my position.


With respect, if your intent was not to denigrate, then you probably should have just skipped this whole paragraph. It gives your entire post a dismissive tone. It also makes the bolded read as don't post in "my thread" if you don't agree with me, and you can be assured i won't again.


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## mikey

Dan_S said:


> With respect, if your intent was not to denigrate, then you probably should have just skipped this whole paragraph. It gives your entire post a dismissive tone. It also makes the bolded read as don't post in "my thread" if you don't agree with me, and you can be assured i won't again.



It was not my intent to upset you, Dan. I actually worried about how to word my post so as to avoid that. However, it is difficult to portray intent with words and I cannot help how you perceive things. With that said, I was not being dismissive in the least. I am more than willing to discuss tool geometry with you here or elsewhere - I was simply giving you the choice. 

You may not believe me but I understand how you feel. You contributed and I called you out on multiple points - who wouldn't be upset? And yet, the intent was to clarify; it had nothing to do with *me* being right. So, participate or don't participate, the choice is yours. 

Oh, just so its clear, this is not "my thread". It is our thread, me and all the guys who have posted to it, and that includes you. The intent of the thread was to help guys understand how (and what and why) to grind a good tool and then let the tools and the results prove themselves.


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## Aukai

Got my models when I got home last night, hope to start on them tonight.


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## Aukai

Well my ego got a check tonight. My finess skills need some tuning. The grinding will take a couple of tries to get exact, and the honeing is an animal.


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## mikey

Don't forget - we need pics!


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## Aukai

I took a couple, but not ready to share yet.


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## mikey

No pressure, Aukai. If you care to share at some point, fine. If not, that's okay, too.

Believe me, I know how hard it is to grind a tool in the beginning but take your time, it will come.

If you're ever in Honolulu, let me know and I'll give you a hand-on demo on tool grinding.


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## Aukai

Thank you I will take you up on that. Learning the belt sander is part of the issue, and keeping the surfaces flat when honing is another.


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## Z2V

Yeah, I'll take you up on it too, I'll get my bus ticket tomorrow!!


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## thomas s

Z2V I hope that bus can float.


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## Z2V

Those small details, they get me every time!


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## ddickey

I'm coming too!


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## ttabbal

All I was going to do was have people ship blanks to mikey's place, now we're arranging a party at his place...


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## mikey

You guys cracked me up this morning! If any of you ever do visit Honolulu, let me know and we'll get together for a tool grinding thing. My shop extension should be done by then and I'll be able to access all my machines so we can even test the tools. Would be fun!


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## mikey

Aukai said:


> Thank you I will take you up on that. Learning the belt sander is part of the issue, and keeping the surfaces flat when honing is another.



The key issues with a belt sander will be the table and platen. You have a Jet 2x42 and the table, while adequate for most tasks, is not set up from grinding tools. It will work; you just have to get the angles set right. The platen is attached only on the bottom so it can flex; that makes holding accurate angles difficult. 

Can you post a pic of how the platen is configured? Maybe from the side?

Honing can be tricky for some. What I do is to hold the stone in one hand and the bit in the other. Then I place the face I'm honing in full contact with the stone and lock my wrists. Then I use a pulling motion to make a full stroke on the stone and then re-register the face and make another stroke. You don't need a lot of pressure with a diamond stone; what you are trying to do is not allow your hand angles to change. I find that if I use a lot of tension in my wrists, it is less accurate. Try to relax but keep your wrists locked. Hard to explain but it doesn't take a lot of muscle power to lock your wrists; just don't let them move. Oh yeah, I do all of this under a bit of running water to keep the grit off the stone but a basin that you can dip into works fine, too.


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## Aukai

Back shot..If..the picture here is cropped, click on it to see full view


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## mikey

I would make a new platen from 1/4" thick steel. Make the base, weld the platen to it, then box the sides with flat plates welded to the platena and base. Then I would make the slot long enough to allow you to epoxy on a Pyroceram liner. A boxed structure should be solid enough.


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## Fallriverbryan

Models arrived from Canada today' They look great. Awesome job on the packaging. Now, have to find some me time.


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## Aukai

mikey said:


> I would make a new platen from 1/4" thick steel. Make the base, weld the platen to it, then box the sides with flat plates welded to the platena and base. Then I would make the slot long enough to allow you to epoxy on a Pyroceram liner. A boxed structure should be solid enough.


I can work on that. Shucks now I'm back at a 1,000,000, and 1 things to do again.....


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## mikey

Aukai said:


> I can work on that. Shucks now I'm back at a 1,000,000, and 1 things to do again.....



Yeah, sorry about that but a platen that stays flat and solid is a joy to use. One that moves in use is next to worthless. Once you get the platen sorted, you need to figure out how to index the table quickly and precisely. THEN tool grinding is simple and easy. I kid you not, I can now grind a square tool in about 3 minutes with these new ceramic belts, and the tool will be accurate.


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## mikey

Fallriverbryan said:


> Models arrived from Canada today' They look great. Awesome job on the packaging. Now, have to find some me time.



I'm interested to hear how they work for you, Bryan. Different from your tools at work, that's for sure.


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## Aukai

I'm getting much faster at not getting it quite rightLOL ran out of time tonight. I have to go back,  and get a couple more 3" pieces.


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## mikey

Aukai, are you using a push block or just your hands? 

Draw the line on top of the tool and keep that line parallel with the belt. As you get closer and closer to the line, it will be easier to do this. Take your time and grind one single flat using the push block to steer.


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## Aukai

mikey said:


> Aukai, are you using a push block or just your hands?
> 
> Draw the line on top of the tool and keep that line parallel with the belt. As you get closer and closer to the line, it will be easier to do this. Take your time and grind one single flat using the push block to steer.


The shorter length added to the heat, I am using a block, give it another shot tomorrow, sneaking up on it....


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## bfk

Apologies to those of you waiting for the samples. I thought I had sent them on weeks ago, but they were still on the bench, hiding under some papers. It was only when Z2V asked about them last night that I realized my mistake. 
They are now on their way to California. 

I owe you all one virtual beer. May be turned into an actual beer if you visit Eugene. 

Brian


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## EmilioG

Great thread. Thank you Mikey. Doing this is help so many and saving a lot of good lathe tools from a horrible, munged up, distorted end.
I'll start with a bench grinder until I can get a decent belt sander/platen mod set up. Looking at the Metabo bench grinder for now.
Ordering some key stock from McMasters while my C-L, Rex and MoxMax bits patiently await their turn.  I'll be using the shops lathe for now, (alas, I too am latheless.   I see that a lot of people are now using tool holders with inserts. Future? I still want to learn to grind by hand. Thanks Mikey.


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## mikey

Thanks, Emilio. I hope this thread helps you to grind a good tool that will go with your future lathe. Knowing you, it will be a really good one. 

Yeah, most hobby guys use inserted carbide tools and I don't blame them - easy to use, no grinding and so on. I have them, too, and I also know how to use them but since they are appropriate for only a small proportion of my work I use HSS most of the time. I'm fortunate that I have the option to choose; way too many guys don't.


----------



## mikey

Hey guys, I just noticed that we have over 13,000 hits on this thread - is that amazing or what!!


----------



## Z2V

Mikey’s models are making their rounds. The feedback has been very good from all that have had them. The list is getting short so if your on the list and have not had them yet you are likely next. 
If you have been following this thread and have note put your name on the list now is a great time to do so.

Again, Mike, thanks for putting this together for all our benefit.


----------



## mikey

Z2V said:


> Again, Mike, thanks for putting this together for all our benefit.



You're welcome, Jeff. It's been a fun thread and seeing you guys grind and enjoy your tools has made all the work worthwhile. 

My little shop extension has reached the stage where everything, including my grinder, is buried or inaccessible so I cannot grind the shear tool yet but I have not forgotten. I will get to it and post the results here when I do.


----------



## tweinke

I also want thank you guys again! I never posted pictures and well I do have a couple but can not figure out how to get them from my phone to the computer, that and a lack of time. I have spent my free time dreaming up a 2x72 grinder that will not require any welding. the grand plan for no welding is because it will be a challenge for my mind and may help someone else with no welder just a mill and possibly a lathe. So far things appear promising, I have the main body figured out and am working on the tensioner arm. I need to get more steel to continue but I hate to go back to the local welding shop because he offered to sell me his carbide grinder for $100.00. Its behind a bunch of stuff so I couldn't see it real well but it appears to be a Baldor. I'm torn on that deal and probably should get it or regret it later. Any input on that? The belt grinder would continue either way.


----------



## Z2V

I say get it, you can never have too many tools


----------



## Aukai

Automotive serpentine belt tensioner, not sure what application, but there are some wide ones.


----------



## mikey

tweinke said:


> ... he offered to sell me his carbide grinder for $100.00. Its behind a bunch of stuff so I couldn't see it real well but it appears to be a Baldor. I'm torn on that deal and probably should get it or regret it later. Any input on that? The belt grinder would continue either way.



Buy it, quick!


----------



## Randall Marx

If you don't want it, Todd, Get it and I'll buy it from you!


----------



## Z2V

Why didn’t I think of that.....^^^


----------



## Randall Marx

Just trying to help! hehehe


----------



## tweinke

The deal has been made  for the grinder, may have to store it in the living room..........


----------



## Randall Marx

Is that just because you have the same problem as many of us: not nearly enough room in the shop? Hope you get to put the grinder to good use!


----------



## ttabbal

I'm thinking about one of my first projects being a belt grinder. Just got a free treadmill to tear down for the  motor and maybe some other useful bits. The lathe is on the way and I could use it to make the pulleys. I kind of liked making the tool copies.


----------



## tweinke

Oh oh I see that you are heading toward a tool dependency issue!  The first stage is justifying the making or purchase of more tools. That's ok though we are here to help you!



ttabbal said:


> I'm thinking about one of my first projects being a belt grinder. Just got a free treadmill to tear down for the  motor and maybe some other useful bits. The lathe is on the way and I could use it to make the pulleys. I kind of liked making the tool copies.


----------



## tweinke

Randall Marx said:


> Is that just because you have the same problem as many of us: not nearly enough room in the shop? Hope you get to put the grinder to good use!




Yup. Note to self when you build a garage or storage building, plan for the size you need then double it and when building double again. Surprisingly the wife actually supported this purchase.


----------



## ttabbal

tweinke said:


> Oh oh I see that you are heading toward a tool dependency issue!  The first stage is justifying the making or purchase of more tools. That's ok though we are here to help you!




Help contribute to my delinquency you mean!   Tool guys are worse than drug pushers!


----------



## Z2V

My belt grinder is slowly coming together. Threaded some 1/2” rod for the wheels this evening and will cut some spacers tomorrow after I get home from defensive driving. I have a 3 hp treadmill motor for it. Heck the table it’s sitting on was a treadmill.
I plan to make some aluminum wheels but these will do to get it up and running.
Yes Mikey, I have glass for the platen too, thanks for the tip!


----------



## tweinke

Z2V your grinder is looking mighty fine! Got the same wheels for mine and like you will make the next set if they don't hold up.


----------



## mikey

Man, you guys are making me jealous with your grinders! One day, one day ...


----------



## thomas s

Jeff,  nice job on the grinder.


----------



## jlsmithseven

Wow this thread really kicked off. Is there a pic with all the models included? I forgot I actually had this great book on lathe tooling and function.
I highly recommend this book for anyone getting into lathes. It has numerous ways to ground tool bits for the lathes and some very good educational material for threads and other things. Great book for referencing.


----------



## mikey

Hey Justin. Post 102 has pics and post 104 will tell you how to grind them.

You're right - the response to this thread has been amazing!


----------



## rwm

Can we address belt grinders a little? I was thinking about adding a pyoceram platen to my grinder but I have a safety concern. I know how to secure them correctly but what happens if/when these things come loose? Has anyone had personal experience with this? Even with safety glasses I can envision shards of glass hitting my neck and face. Am I overestimating the risk?

I have a tool blank that is Rex 49. I have tried to grind it but the belt will not really make a dent. I am running 60 grit Zirconia at about 5000 SPFM. There is no way to grind this blank on my machine. Am I doing something wrong? Do I need higher SPFM?
Robert


----------



## mikey

rwm said:


> Can we address belt grinders a little? I was thinking about adding a pyoceram platen to my grinder but I have a safety concern. I know how to secure them correctly but what happens if/when these things come loose? Has anyone had personal experience with this? Even with safety glasses I can envision shards of glass hitting my neck and face. Am I overestimating the risk?



I have had one Pyroceram liner come loose. My belt broke and knocked the liner loose and it fell and contacted my lower drive wheel. The liner itself did not crack or chip and since the belt had snapped, nothing was there to trap it. I did not have support screws or a ledge under the liner but this would have prevented it from dropping down. The JB Weld I used lasted over 10 years under pretty frequent use so I was happy with that product. My new liner does have two 6-32 SHCS underneath it and I used JB Weld again; so far, so good. I know of no way to guarantee a liner won't come loose. About all you can do is to make sure you have a support under the liner and use a good adhesive.

I have never ground a Rex 49 blank. I don't even know what the metallurgy is so I can't help here. Crucible's online info does not even list it. That said, I've not seen a HSS blank that a belt cannot cut. I've ground 8 and 10% cobalt bits with no issues so I'm not sure what is in that Rex 49 to make it so resistant. Does anyone else know what's in this stuff?

I wonder if a ceramic belt will cut it, Robert.


----------



## rwm

I don't know what the heck it is but it sure is hard! I ruined a belt already. These are high quality Zirconia belts from McMaster. At the rate I am going it would take over an hour to grind each facet of the tool.
I have ordered the ceramic belts you mentioned earlier. We shall see if that improves the cutting action.
I guess someone needs to produce a belt with PCD!
Thanks for your reply.
Robert

EDIT:
Oops...Triatic makes PCD belts if you want to pay for them! The 1 x 48 is $200. I wonder how long it would last? 
R


----------



## Z2V

Robert
Are you sure on the Rex “49”?
There is no mention of a Rex 49 in this 400 pg book. It jumps from 45 to 54. Just trying to identify it for you.


----------



## mikey

I would just toss that bit and use one of known composition. An M2 or cobalt bit will cut almost anything we're likely to encounter,  unless you're working with some unusual stuff.


----------



## rwm

I am beginning to think this is of extraterrestrial origin...
Robert

EDIT:

Found this-
According to the Techstreet Store:
"Rex 49 is a high-speed tool steel designed to give much
longer life in machining difficult to cut materials such as
highly alloyed steels, stainless steels, superalloys and
titanium. Rex 49 heat treated to 67/69 Rockwell C makes
it outstanding for difficult machining operations."

"After much research, REX 49 chemical analysis % was
found within the pages of a declassified Federal Document:
Carbon - 1.10
Manganese - 0.45
Silicon - 0.30
Chrome - 4.25
Tungsten - 6.75
Molybdenum - 3.75
Vanadium - 2.0
Cobalt - 5.0"

Personally, I believe Crucible/Rex had a contract with the Federal Government that allowed them to reverse engineer materials from the fragments of crashed alien spacecraft.
R


----------



## Z2V

I asked my father ( retired Crucible sales rep of 30 yrs) and he wasn’t familiar with that number either. You might just be right on it’s origin.


----------



## larry4406

Z2V said:


> I asked my father ( retired Crucible sales rep of 30 yrs) and he wasn’t familiar with that number either. You might just be right on it’s origin.


Wait - let me get my tin foil hat


----------



## Z2V

DELETED


----------



## Z2V

I didn’t think about the fact that my father has been retired for 16 yrs, the book I have is dated 1999. I guess I’m a little behind the time. 
Cheers!


----------



## EmilioG

Mikey, I finally got the models. They are like nothing I've seen.  Now on to keystock so I don't ruin my USA lathe bits.
I also have a dozen or so that a friend gave to me that are ground but need re-grinding and honing. I'll post a pic soon.
It;s great to see the real thing up close.  I'll post images of what I've ground after some practice. These models are invaluable.


----------



## Z2V

Emilio
Glad to hear that you got the models.


----------



## mikey

EmilioG said:


> Mikey, I finally got the models. They are like nothing I've seen.  Now on to keystock so I don't ruin my USA lathe bits.
> I also have a dozen or so that a friend gave to me that are ground but need re-grinding and honing. I'll post a pic soon.
> It;s great to see the real thing up close.  I'll post images of what I've ground after some practice. These models are invaluable.



Take your time, post pics when you can. If I can, then you can (grind them, I mean)! When you buy your lathe they will come in handy.


----------



## mikey

Z2V said:


> Emilio
> Glad to hear that you got the models.



Jeff, thanks again for helping to get the models out to the guys!


----------



## bfk

Emilio, glad to hear they got to you. They are pretty amazing. 
I was just using the tool I made to turn some 6061 and was able to take .001 off a 16mm long 3mm diameter pin, I could never do that before.

Many thanks to Jeff and Mikey.


----------



## EmilioG

Which DTI model or models, are accurate to use in a lathe when taking small cuts? To gage travel?


----------



## mikey

EmilioG said:


> Which DTI model or models, are accurate to use in a lathe when taking small cuts? To gage travel?



You can use whatever you have that will directly read cross slide travel. Doesn't mean the tool will make the cut but you can try it. A 0.001" deep cut is no problem, and usually half that is easy, too. The tool can usually cut what you dial in but on a thin work piece that deflects you may have some variation with really fine cuts.


----------



## Twirpunky

I taught machine shop classes for several years at a 2-year college.  I made up some sample cutting tools out of wood blocks.  I would make them out of 1" square wood strips in the wood shop.  I could write on them with marking pens for the cutting edges, relieve angles ect.   The students would then practice on wood blanks until they had the angles and clearance down.  I always left several examples of wood cutting tools around the shop for reference.  Of all things I taught, hand grinding a good HSS tool bit was the hardest concept for the students to grasp.

Dennis


----------



## mikey

rwm said:


> View attachment 247609
> 
> I am beginning to think this is of extraterrestrial origin...
> Robert
> 
> EDIT:
> 
> Found this-
> According to the Techstreet Store:
> "Rex 49 is a high-speed tool steel designed to give much
> longer life in machining difficult to cut materials such as
> highly alloyed steels, stainless steels, superalloys and
> titanium. Rex 49 heat treated to 67/69 Rockwell C makes
> it outstanding for difficult machining operations."
> 
> "After much research, REX 49 chemical analysis % was
> found within the pages of a declassified Federal Document:
> Carbon - 1.10
> Manganese - 0.45
> Silicon - 0.30
> Chrome - 4.25
> Tungsten - 6.75
> Molybdenum - 3.75
> Vanadium - 2.0
> Cobalt - 5.0"
> 
> Personally, I believe Crucible/Rex had a contract with the Federal Government that allowed them to reverse engineer materials from the fragments of crashed alien spacecraft.
> R



Robert, I just saw your edit. Rex 49 has a fair amount of Molybenum compared to most HSS but the composition is not that different from other tool bits. It should tolerate more red heat, though. I honestly don't know why it would be such a bear to grind unless its the increased carbon. T15 has increased carbon and it can be tough to grind, too, so maybe that's it. Still, I should think a ceramic belt should handle it. Please let us know how your ceramic belts work on this one.


----------



## Ken from ontario

jlsmithseven said:


> Wow this thread really kicked off. Is there a pic with all the models included? I forgot I actually had this great book on lathe tooling and function.
> I highly recommend this book for anyone getting into lathes. It has numerous ways to ground tool bits for the lathes and some very good educational material for threads and other things. Great book for referencing.
> View attachment 247547


Here's the pdf version(I hope it is alright to post these 2 links):

http://vintagemachinery.org/pubs/1617/3789.pdf
or this one:
http://campkahler.com/files/How_to_Run_a_Lathe_SB_1of2.pdf


----------



## HBilly1022

I was having issues with keeping my tool bit sharp. I would grind it through several belt grits, up to 240 grit, then use a hone to finish it. It would cut great for a for short while, just a few passes and then I would have to hone it again. I was starting to think I must have over heated the HSS bit during grinding or something to lessen the hardness. However, yesterday I grabbed a piece of 2" diameter mild steel that I bought from a machine shop and turned that on the lathe and bored it for some collars I was making. I couldn't believe how nicely the tool cut and the great finish it left. I could take deep cuts and really fine ones of 0.001" and leave a great finish. Plus the tool stayed sharp. I believe I have discovered the problem. It was not the cutting tool or my grind, it was the unknown scrap yard steel. Some of the stuff I tried to mill recently would just kill my HSS end mills after only milling a few square inches.

I took the same grind principle to my HSS fly cutter and after using similar grind angles, the thing cut awesome. I was having issues with mill scale dulling my HSS end mills but with the fly cutter grind I used, the tip would get under the mill scale and just chip it away, leaving a really nice finish. It also stayed sharp for a long time. 

Thanks to this thread and Mike's efforts I am starting to understand how to grind a better cutter.

Thanks Mike!!!!!


----------



## jlsmithseven

To all of you grinding these lathe bits, I highly recommend grinding a chip breaker on the top. I was introduced this concept this year and it works amazing. No more tangling up of long stringy chips or any chips building on tool. They just go on top of the chip breaker and fall right down into chip pan. It's made a huge difference for me.

I've uploaded a picture showing what I mean.
*In the red outline*, use a stone or grinder to make the end of the tool rounded.
*In the blue outline*, use the side of a bench grinder to make a slot on top of the tool.
*The yellow box* is supposed to be a pedestal grinder wheel. Use where the side meets the front edge to do the chip breaker.
Looking at this image, the cutting tool is like you're looking straight down on it from above.


----------



## mikey

HBilly1022 said:


> I was having issues with keeping my tool bit sharp. I would grind it through several belt grits, up to 240 grit, then use a hone to finish it. It would cut great for a for short while, just a few passes and then I would have to hone it again. I was starting to think I must have over heated the HSS bit during grinding or something to lessen the hardness. However, yesterday I grabbed a piece of 2" diameter mild steel that I bought from a machine shop and turned that on the lathe and bored it for some collars I was making. I couldn't believe how nicely the tool cut and the great finish it left. I could take deep cuts and really fine ones of 0.001" and leave a great finish. Plus the tool stayed sharp. I believe I have discovered the problem. It was not the cutting tool or my grind, it was the unknown scrap yard steel. Some of the stuff I tried to mill recently would just kill my HSS end mills after only milling a few square inches.
> 
> I took the same grind principle to my HSS fly cutter and after using similar grind angles, the thing cut awesome. I was having issues with mill scale dulling my HSS end mills but with the fly cutter grind I used, the tip would get under the mill scale and just chip it away, leaving a really nice finish. It also stayed sharp for a long time.
> 
> Thanks to this thread and Mike's efforts I am starting to understand how to grind a better cutter.
> 
> Thanks Mike!!!!!



I recall telling you that if the edge wasn't holding up that maybe it wasn't sharp to begin with. I was clearly wrong, HB, and I apologize to you. I didn't realize you were working with No-can-cutium!

At least for the more common stuff we cut, your tools seem to be working well for you and that is awesome. Now I would encourage you to experiment and teach yourself how to alter your tool angles to work with different materials because that is where the magic lies. If you think your square tool works well with mild steel or aluminum or stainless steel, wait until you work with a tool with angles that are optimized for those materials.


----------



## mikey

jlsmithseven said:


> To all of you grinding these lathe bits, I highly recommend grinding a chip breaker on the top. I was introduced this concept this year and it works amazing. No more tangling up of long stringy chips or any chips building on tool. They just go on top of the chip breaker and fall right down into chip pan. It's made a huge difference for me.
> 
> I've uploaded a picture showing what I mean.
> *In the red outline*, use a stone or grinder to make the end of the tool rounded.
> *In the blue outline*, use the side of a bench grinder to make a slot on top of the tool.
> *The yellow box* is supposed to be a pedestal grinder wheel. Use where the side meets the front edge to do the chip breaker.
> Looking at this image, the cutting tool is like you're looking straight down on it from above.
> 
> View attachment 247736



Thanks, Justin. 

Guys, let us know how this works for you.


----------



## HBilly1022

mikey said:


> I recall telling you that if the edge wasn't holding up that maybe it wasn't sharp to begin with. I was clearly wrong, HB, and I apologize to you. I didn't realize you were working with No-can-cutium!
> 
> At least for the more common stuff we cut, your tools seem to be working well for you and that is awesome. Now I would encourage you to experiment and teach yourself how to alter your tool angles to work with different materials because that is where the magic lies. If you think your square tool works well with mild steel or aluminum or stainless steel, wait until you work with a tool with angles that are optimized for those materials.



Being inexperienced I had no idea that the type of steel had that much influence on how it machined. I figured if I could file it then it must be soft enough to machine with regular cutting tools. There's a machinist salesman at the tool store where I get most of my stuff and I described what was happening and he quickly straightened me out. I guess I should have just pointed out ALL the information involved in what I was doing and _using_.

Edit: Mike, as I recall at the beginning of this thread you said it took you 15 years to figure this out (or something like that - memories not what it used to be). I've been at this part time for about 2 years now and I have only just ground my first good HSS tool bit and only because of this thread. I doubt I will ever get to a point where I will experiment with different angles for different materials (especially when I don't even know what the material is) lol. Too many variables: cutting speeds, DOC, feed rates, front clearance, back rake, etc. and then throw in some unknown steel and a rookie. But at least now I am not totally ignorant about proper grinding angles and the _need_ for the edge to be honed. It's all part of the learning experience.


----------



## mikey

That's the issue with buying scrap material; we don't know what we're working with. I tried to cut an old axle from some vehicle once and burned up a HSS tool, then I burned up a carbide insert and then I cut it with a brazed carbide tool but the finish was really ugly. That stuff went in the bin.


----------



## HBilly1022

mikey said:


> That's the issue with buying scrap material; we don't know what we're working with. I tried to cut _an old axle from some vehicle_ once and burned up a HSS tool, then I burned up a carbide insert and then I cut it with a brazed carbide tool but the finish was really ugly. That stuff went in the bin.



That's hilarious ... I have an axle in my steel bin and thought it was an awesome score because I got it for free. Maybe it will be a great score .......... but it doesn't look promising after your comments.  Sometimes the mystery stuff works out and other times not so much, lol.


----------



## mikey

HBilly1022 said:


> Edit: Mike, as I recall at the beginning of this thread you said it took you 15 years to figure this out (or something like that - memories not what it used to be). I've been at this part time for about 2 years now and I have only just ground my first good HSS tool bit and only because of this thread. I doubt I will ever get to a point where I will experiment with different angles for different materials (especially when I don't even know what the material is) lol. Too many variables: cutting speeds, DOC, feed rates, front clearance, back rake, etc. and then throw in some unknown steel and a rookie. But at least now I am not totally ignorant about proper grinding angles and the _need_ for the edge to be honed. It's all part of the learning experience.



You're right, and I do realize that messing with tool geometry is not something everyone wants to do. I just wanted to say that if you should decide to try it one day, I've given you what I know about it so you can do it.

Let me give you one tool I think will be useful to you. It is my aluminum tool; since we hobby guys turn a lot of that material it might come in handy. This tool will make a square tool look crappy when turning aluminum.

Shape: general purpose
Relief angles: 15 degrees for side and end
Side Rake: 18 degrees
Back Rake: 40 degrees
Nose Radius: 1/32"
This thread has allowed us to communicate in the shorthand given above and you should be able to reproduce my aluminum tool with ease. This tool will cut deeper, finish finer and if you get the feed right, it will produce chips instead of stringers on your roughing cuts. It will clear chips so well that you won't have any chip welding (BUE = built up edge) and it will take an extremely fine cut so coming in on size is simple. 

Try this tool, your first material-specific tool, and you'll see why our square tool is just the beginning.


----------



## Bamban

Hillbilly,

Don't be surprised that sometimes same material from the same supplier may not cut the same.

One time I had a couple of 416R barrel blanks shipped to me in the same box, one would  chip, and the other would string on the same set up.


----------



## HBilly1022

mikey said:


> You're right, and I do realize that messing with tool geometry is not something everyone wants to do. I just wanted to say that if you should decide to try it one day, I've given you what I know about it so you can do it.
> 
> Let me give you one tool I think will be useful to you. It is my aluminum tool; since we hobby guys turn a lot of that material it might come in handy. This tool will make a square tool look crappy when turning aluminum.
> 
> Shape: general purpose
> Relief angles: 15 degrees for side and end
> Side Rake: 18 degrees
> Back Rake: 40 degrees
> Nose Radius: 1/32"
> This thread has allowed us to communicate in the shorthand given above and you should be able to reproduce my aluminum tool with ease. This tool will cut deeper, finish finer and if you get the feed right, it will produce chips instead of stringers on your roughing cuts. It will clear chips so well that you won't have any chip welding (BUE = built up edge) and it will take an extremely fine cut so coming in on size is simple.
> 
> Try this tool, your first material-specific tool, and you'll see why our square tool is just the beginning.



WOW that's a LOT of back rake. I'll be sure to use this the next time I turn aluminum, although that could be a while. In the 2 years I've been playing around in this hobby, I've only turned aluminum 2 or 3 times. Pretty much everything I do is with mystery steel. I do remember getting BEU when I did turn some Al and if I recall right it was hard to get off the tool.


----------



## mikey

HBilly1022 said:


> WOW that's a LOT of back rake. I'll be sure to use this the next time I turn aluminum, although that could be a while. In the 2 years I've been playing around in this hobby, I've only turned aluminum 2 or 3 times. Pretty much everything I do is with mystery steel. I do remember getting BEU when I did turn some Al and if I recall right it was hard to get off the tool.



Do yourself a favor and grind this tool, guys. 40 degrees may seem like a lot compared to other tools but the standard angle tables call for 35 degrees and 40 degrees is just a bit more. That little bit more does several things:

 1) it puts the cutting forces at the very tip of the tool so it finishes really nicely. This is why the nose radius is what it is. Visualize the top plane of the tool: you have side rake and back rake tilting the cutting surface to the side and back, and the nose radius is accordingly tilted off the the right. With the increased relief angles minimizing contact, the contact point of the tool is almost like a shear tool except it is round, not a straight line, so it is not limited in its depth of cut. If you cannot get a mirror finish with this tool then you didn't hone it right.

2) it greatly accelerates and thins the chip. Coupled with the increased side rake, chip velocity is significantly increased. This pulls a lot of heat out of the cut and this eliminates chip welding on the tool; I have yet to have a BUE on this tool, even in gummy hardware store aluminum, and this is especially true if I lube the cut. Take a big cut and then feel the stock; it will be cool.

3) this tool has increased relief angles, increased side rake and increased back rake. It cuts with the lowest cutting force of all my tools. It will take a 0.250" deep cut (0.500" reduction in diameter) on my 11" lathe without effort and it will produce chips, not stringers, if I feed fast enough. And it will take a 0.0005" finish cut with minimal deflection. In aluminum, it is the most accurate tool I have. 

The geometry of this tool took about 6 months of trial and error to be finalized. I suspect I went through about 6 feet of 6061 in the process. You might be able to improve on this tool in your trials but I can't. It is as good an aluminum cutting tool as I can make.


----------



## EmilioG

Any tips on grinding P3 part off blades? How are they kept sharp? How are they prepared for use?


----------



## mikey

EmilioG said:


> Any tips on grinding P3 part off blades? How are they kept sharp? How are they prepared for use?



I use a 7 degree clearance angle up front, ground square across the nose. Then very lightly deburr the top flat and you're ready to cut. I flatten the top every few months or so and maybe freshen the grind about once a year. Cuts fine for me.


----------



## rwm

Some followup: I got several of the ceramic belts listed earlier and they were able to cut the Rex alien alloy much quicker. I have another suggestion: for the rough in try a hand held angle grinder to remove the bulk material then finish the surfaces on the belt grinder. It will save wear on the belt and is especially helpful for large angles (40Deg back rake.)
Unfortunately, I ground the aluminum knife tool and I am less than impressed with the results. I used a 15 deg side relief angle, a 15 deg nose relief angle, a 15 deg rake and a 40 deg back rake angle. That much back rake looks weird. I tried to grind a small radius on the end with a stone. The finish the tool leaves is very poor. I may need a larger radius at the tip. 
I have a question about grinding that. If the side and end relief angles are each 15 deg, then the relief angle at the middle of the tip is actually greater than 15 deg. In other words if you set the grinder table at 15 deg and grind a radius you will actually be making the relief angle smaller. Is that what I should be doing?
Robert


----------



## mikey

rwm said:


> Some followup: I got several of the ceramic belts listed earlier and they were able to cut the Rex alien alloy much quicker. I have another suggestion: for the rough in try a hand held angle grinder to remove the bulk material then finish the surfaces on the belt grinder. It will save wear on the belt and is especially helpful for large angles (40Deg back rake.)
> Unfortunately, I ground the aluminum knife tool and I am less than impressed with the results. I used a 15 deg side relief angle, a 15 deg nose relief angle, a 15 deg rake and a 40 deg back rake angle. That much back rake looks weird. I tried to grind a small radius on the end with a stone. The finish the tool leaves is very poor. I may need a larger radius at the tip.
> I have a question about grinding that. If the side and end relief angles are each 15 deg, then the relief angle at the middle of the tip is actually greater than 15 deg. In other words if you set the grinder table at 15 deg and grind a radius you will actually be making the relief angle smaller. Is that what I should be doing?
> Robert



Well, at least we know the ceramic belts will cut alien steel. Thanks for the follow up.

I don't use the aluminum tool angles for knife tools. I use them on a general purpose tool; finishes incredibly well for me. A knife tool doesn't have the right lead angle for general and finish work and it will leave spirals in the finish. Try grinding a general purpose shape and see what happens.

As for the nose radius, you have the side and end relief angles intersecting with the side and back rake angles - a complex shape made up of three planes that connect at the tip. Controlling the grind of the nose radius with a belt or wheel is difficult and it is really easy to alter the angle of the interstection of the relief and rake angles, so I form the radius on with a diamond stone. This allows you to use the front of the tool, where the side and end relief angles meet up front, to guide the angle of your stone. 

This becomes really important on an aluminum cutting tool that has large back rake angles because the back rake focuses all the cutting forces at the tip of the tool. You are correct in that this narrows the cutting/contact area at the very tip and this is why I use a larger than normal 1/32" nose radius on this tool.

Robert, try grinding a general purpose shape instead of a knife tool and put a 1/32" radius on it. The tool will cut well for you.


----------



## Z2V

Hello Mike
Do these pics accurately represent your general tool for aluminum?
I have not honed it yet or put nose radius on it. Just hoping I’m on the right track with the angles. I set table at 15* and made the side and end cut angles then put table at 18* and marked table on the side at 40* and ground that to what you see in the pics.
I will say for sure I will not be using a bench grinder to grind tools any more. I got the belt grinder up and running, WOW, what a difference!!


----------



## rac1812

mikey said:


> At this point, I realize I’m doing a complete brain dump on tool grinding. By the time I’m done with this you guys will know what I know about the subject. Some of you may be wondering what brought this on.
> 
> I suddenly lost my best friend a few years ago and it broke my heart. We were supposed to grow old together, going fishing and telling each other lies. He was a master cabinetmaker with so much to give, so much to teach but he never got the chance. Now I realize that none of us knows how much time we have; I’m not that old yet but my friend was 12 days younger than me so you never know. So I am passing on the information I have while I have the chance. I truly do appreciate the HM community and I cannot think of a better bunch of guys to pass this stuff to. If it helps you then I’ll be happy but I also hope it makes my friend happy to know that I did what he could not.



Thank you for sharing your knowledge and experience.  I am a newbie and recently discovered this site.  I have been reading and enjoying this thread from the beginning.  Your friend would be proud  of you and the legacy that you leave behind across the globe with the WWW.
Bob C
Hammond, ON Canada


----------



## mikey

Z2V said:


> Hello Mike
> Do these pics accurately represent your general tool for aluminum?
> I have not honed it yet or put nose radius on it. Just hoping I’m on the right track with the angles. I set table at 15* and made the side and end cut angles then put table at 18* and marked table on the side at 40* and ground that to what you see in the pics.
> I will say for sure I will not be using a bench grinder to grind tools any more. I got the belt grinder up and running, WOW, what a difference!!
> View attachment 248717
> View attachment 248718
> View attachment 248719
> View attachment 248720
> View attachment 248721
> View attachment 248722



Looks really good, Jeff. Take a look at the tip and you'll see that the tip is comprised of the three planes I mentioned above. You can see that the tip is at rather a significant angle. The somewhat smaller nose radius I prefer will be too small on this tool because of that angle; a slightly larger radius works better. Give the tool a try and let us know what you think. 

You've discovered the same thing I did many years ago. A belt sander is a much better lathe tool grinder than a bench grinder. If more guys tried this on a well configured belt sander there would be far more of us than there are.


----------



## mikey

rac1812 said:


> Thank you for sharing your knowledge and experience.  I am a newbie and recently discovered this site.  I have been reading and enjoying this thread from the beginning.  Your friend would be proud  of you and the legacy that you leave behind across the globe with the WWW.
> Bob C
> Hammond, ON Canada



Thank you for your kind sentiments and sensitivity, Bob. I think of him every day, and I miss him so very much. It has been a privilege to work with all of you and I do hope the information here helps you to enjoy your lathes more. My friend was fond of teaching others, including me, and one of his favorite sayings was the one Todd referred to - "Teach a man to fish ... "


----------



## Z2V

Well I cleaned up the aluminum tool I ground the other night. I’m not sure if I made it the way Mikey describes it but I will say that what I have cuts really well and does leave a great finish. Almost a mirror finish and as smooth as glass. 
I will definitely keep this one.
Thanks Mikey


----------



## mikey

Z2V said:


> Well I cleaned up the aluminum tool I ground the other night. I’m not sure if I made it the way Mikey describes it but I will say that what I have cuts really well and does leave a great finish. Almost a mirror finish and as smooth as glass.
> I will definitely keep this one.
> Thanks Mikey



Sorry I wasn't clear on that but you got all the angles right, Jeff, and you did a really nice job of it, too! Very few guys have actually ground that tool, even though I've described it a few times before. Try comparing it to your square tool and see which one wins out in aluminum; I'm betting on your aluminum tool.

Now try one for brass. Just 15 degree relief angles, no rake angles, general purpose shape and honed well. I also need to show you guys a round nose tool for brass - cuts both ways and leaves a mirror finish.


----------



## Z2V

Mike, I actually did compare it to the square tool with side by side cuts. While the square tool did just fine the aluminum tool left a much smoother finish.


----------



## mikey

Z2V said:


> Mike, I actually did compare it to the square tool with side by side cuts. While the square tool did just fine the aluminum tool left a much smoother finish.



Okay, thanks, Jeff. I really like that tool. I find that if I can dial in the cut, the tool will make the cut.

My belt sander is buried right now so grinding a 3/8" round nose tool will have to wait. If you want to try grinding one yourself, try this: Mark the side of the blank at 3/4", then draw a line from that mark to a point 1/32" on either side of the centerline of the tip of the blank. Set the table to 15 degrees and grind to the line on both sides. Now just round the nose, being careful to keep the radius even from top to bottom at the front of the tool. Hone and you're done. 

This round nose tool will cut brass, mild steel and aluminum. Because it has no rake it is a form tool so you cannot hog material off but it will cut better than you think and produces a nice finish. Start at a low speed, maybe 300 rpm, and slowly increase speed to see what the material wants. I normally use this tool to turn between shoulders on relatively large parts. I part in with a parting tool to define the shoulders and remove the material in between with the round nose tool. Keep in mind that the larger nose radius will produce larger radial forces so deflection can and will occur on thin work pieces. However, with larger work pieces it works well and will cut in both directions. If you choose, you can grind about 10 degrees of back rake (no side rake) into the top of the tool and it will work better with mild steel and aluminum. With zero rake, it produces a near mirror finish in brass. 

Try this one, guys; you will like it.


----------



## mikey

I forgot to mention that your aluminum cutting tool will work really well with most plastics, including Delrin. In my experience, Delrin likes a fairly low speed and higher feed rate. The increased side and back rake on this tool accelerates chip flow so much that heat doesn't build up much in the part so less melting/smearing occurs. As a result, finishes are much improved. What's more, this tool actually cuts with very low forces so there is less spring in the cut and you will find that it can take huge roughing cuts in a single pass but still sizes and finishes very accurately.

If you wish to grind a tool specifically for plastic work, consider the general properties of this class of material. Plastics burn so heat is not a good thing. Plastics are, in general, deformable so it can move away from a cutting edge and then spring back; this makes sizing tricky when cutting to tight tolerances. The deformation and heat intolerance also explain why finishing plastics can be difficult. The solutions to these issues are simple: 

high relief angles (about 18 degrees) to lower cutting forces. This allows the tool to cut readily while improving finishes. Edge life in plastic is affected more by abrasion so you can increase relief angles without much concern. A cobalt tool handles the abrasion better so use it in preference to M2 if you do a lot of plastics.
Boost side rake to increase chip clearance. 18-20 degrees works really well. You will find that a tool with this much side rake cuts really cool and really fast. The part after a big roughing cut will be cool.
Boost back rake. You do not need as much back rake as the aluminum tool but it doesn't hurt. A more reasonable back rake is 25-30 degrees. Trust me; this is enough back rake to keep chip flow moving at high velocities while also thinning the chip. 
Nose radii for plastics should be somewhere near 1/32". Going bigger is not necessary, at least in my experience.
If you want a tool specifically for Delrin, make one with these angles. Like most tools, a few degrees of change can make a big difference and this tool works. Use cobalt, keep it sharp and it will take a huge cut without even slowing down.


----------



## Metal

Sorry ive been foot dragging with the models, my 3d printer and grinder both dumped out on me, I should be able to get them shipped out in the next few days


----------



## lxcnc

I'm going through the instructions, which are very helpful!  Quick question, on the Right Hand Turning tool, the first step is to align your tool rest to 15 degrees.  Do you reset your tool rest after the first step? (Sorry if this has already been answered!)


----------



## mikey

No, you leave it at 15 degrees when grinding all three faces of the Square Tool. Easy, Peasy!


----------



## rac1812

Now that makes sense Mikey and much easier.  I find it difficult to set at exactly 15 degrees, my beltgrinder is a cheap one and there are no easy adjustment scale.  So 15 degrees all around than go back for some fine tuning at 18 or 20 or 10.  I am thinking of making some masters at specific angles then it will be easier to reset the plate.  I have some  very hard bamboo flooring scrap that I will carefully set up than check them against a protractor before I label them.  Once I get a good key stock made I will engrave them with the angles and move on to HSS to try some cuts.

I have made Copies in Words so I can take a copy of your text to the lathe but having difficulties stealing and inserting your pictures in the right place.
I have spent nearly a $100 dollars on various lathe books....some of which were copies of 1917 shop manuals and most have left me blind....BUT your Mastery of plain English and easy flowing style..... is the first thing that really sinks into my hard head.

If you mastered all your explanations into a self contained CD I would be the first one to buy one.  Meanwhile, your thread as motivated me to make a contribution to this forum......... heck of a lot cheaper with better results.

Still a newbie but now slowly climbing the hill.

Bob C.


----------



## Z2V

rac1812
I can send a set of Mikey’s tool models up to you if you would be interested in copying them.
Let me know.
Welcome to H-M also
Jeff


----------



## mikey

rac1812 said:


> Now that makes sense Mikey and much easier.  I find it difficult to set at exactly 15 degrees, my beltgrinder is a cheap one and there are no easy adjustment scale.  So 15 degrees all around than go back for some fine tuning at 18 or 20 or 10.  I am thinking of making some masters at specific angles then it will be easier to reset the plate.  I have some  very hard bamboo flooring scrap that I will carefully set up than check them against a protractor before I label them.  Once I get a good key stock made I will engrave them with the angles and move on to HSS to try some cuts.
> 
> I have made Copies in Words so I can take a copy of your text to the lathe but having difficulties stealing and inserting your pictures in the right place.
> I have spent nearly a $100 dollars on various lathe books....some of which were copies of 1917 shop manuals and most have left me blind....BUT your Mastery of plain English and easy flowing style..... is the first thing that really sinks into my hard head.
> 
> If you mastered all your explanations into a self contained CD I would be the first one to buy one.  Meanwhile, your thread as motivated me to make a contribution to this forum......... heck of a lot cheaper with better results.
> 
> Still a newbie but now slowly climbing the hill.
> 
> Bob C.



Wow, Bob, thank you for your kind words. This thread has revealed some pretty amazing guys that, like you, are now able to grind a decent tool. I am gratified beyond words, Bob. 

@DHarris posted a word doc in post 312 that might save some time. I didn't realize I was so verbose; I think Bonehead is right - too wordy, repetitious and I write like a girl! 

Your template idea is a good one. It will certainly make setting table angles a lot faster and more accurate. If you haven't seen the model tools, why not let Jeff get a set up to you? It might help to see and handle the models.

Welcome to HM, Bob. If I can clarify anything for you, feel free to post or PM me. Post up some pics of your tools and results if you feel like it - we would enjoy seeing them.


----------



## rwm

So I cleaned up my aluminum knife tool first using a finer belt and then by honing. It cuts dramatically better an leaves a nice finish now!
Robert


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## mikey

Glad to hear it, Robert. Had me worried for awhile there.


----------



## ddickey

An FYI.
This seller is selling some blanks for a pretty good price I think. I offered $3 and got one.
https://www.ebay.com/itm/Koncor-Ind...233936?hash=item466e6b42d0:g:QVcAAOSwj99Z78be


----------



## EmilioG

I know we must learn to walk before we run, but, for the sake of this knowledge/thread, what about information on other lathe tools, like chamfer cutters and other form tools? It would be great to have the ultimate lathe tool info thread right here., complete with glossary?


----------



## mikey

EmilioG said:


> I know we must learn to walk before we run, but, for the sake of this knowledge/thread, what about information on other lathe tools, like chamfer cutters and other form tools? It would be great to have the ultimate lathe tool info thread right here., complete with glossary?



Good suggestion, Emilio. Personally, I don't have a lot of knowledge about form tools but I'll give you what I know. 

Form tools have a shape that produces a complementary shape. A threading tool is a 60 degree form tool with a positive shape that produces a precise complementary shape, a 60 degree thread. Similarly, a 45 degree chamfer tool produces a 45 degree chamfer. Both have zero rake and therefore cut with very high cutting forces. Accordingly, depths of cut must be relatively shallow and cutting speeds and feeds must be slow in order to avoid chatter. The larger the contact pattern of the tool, the greater the resistance or cutting force it will produce. In other words, the larger the contact pattern, the shallower your depth of cut must be and the slower your speeds and feeds must be. 

With few exceptions, form tools are usually fixed forms that are stationary. That is, they produce a complementary shape as they are fed into the work but the tool itself is fixed relative to the work. One exception is a graver. It is a form tool with a flat top (more accurately, a side) but it moves, and this makes all the difference. A graver can "form" almost any shape desired because the user is able to change the approach angle of the tool at will. It can also take deep cuts at higher speeds and whisper-thin cuts at will. Of all the form tools I've used, a graver is one of the most useful tools I can think of.

Insofar as the tip geometry of a fixed form tool goes, the most common is a zero-rake or flat topped tool. However, you are not locked into this form. You can give a form tool side rake, back rack, scoop shapes behind the cutting edge, etc. What you will find is that due to the area of engagement, which typically enlarges as the tool is pushed into the work, cutting forces grow very quickly. This can lead to chatter and dig ins that can be rather energetic and dramatic. This is one reason why form tools are best fed by hand; power feed can have some pretty exciting results. 

When grinding a form tool you have control of two basic geometry features: the shape and the relief angles. What works best for me is to first grind the shape I require and simultaneously grind a relief angle that cuts with the least amount of force I can achieve. One example of this is threading tool. If you grind such a tool with the standard relief angles found in a turning tool table, that tool will cut but it will produce a somewhat rough, cracked chip. The finish of the thread will also be rough. However, if you increase the relief angles the chip smooths out, as does the finish. When I experimented with threading tools, I ground tools with different relief angles and found that a 15 degree relief angle produced an acceptable finish while also having decent edge life. It is a balance, you see. I did the same thing with a 30 degree chamfer tool for dressing the end of screws and found that a 15 degree relief angle worked the best for me. Interestingly, the side of a square tool or knife tool works almost as well as my chamfer tool as long as I slow the speed down adequately. 

The other thing I found is that when a form tool has a broad area of engagement, like a radius tool use to cut a half-round groove, the relief angles have to be increased or the tool will chatter severely. Here, it is a balance between cutting ability and edge life. Larger relief angles cut better but don't last as long so you can't have your cake and eat it, too. My suggestion is to start at a conservative relief angle of about 12 degrees and go up until you have a tool that cuts satisfactorily, then keep it sharp. 

Okay, that's my take on form tools. I've made many of them over the years, when and as needed. They are useful to be sure but the main ones I have nowadays are my threading tools, tools for brass and my gravers.


----------



## EmilioG

Thanks Mikey. Very informative indeed. Do you have photos of the gravers? I've seen machinist videos where the graver was hand held to form a dome shape on brass round. What type of graver shape can be used to form dome shapes? I own a few HSS Swiss gravers.


----------



## mikey

EmilioG said:


> Thanks Mikey. Very informative indeed. Do you have photos of the gravers? I've seen machinist videos where the graver was hand held to form a dome shape on brass round. What type of graver shape can be used to form dome shapes? I own a few HSS Swiss gravers.



Have a look here. We discussed gravers briefly: http://www.hobby-machinist.com/threads/gravers-for-turning.56828/

Dome shapes can be formed with a square or round graver, although the round one will do it better. Normally, I rough out with the square tool and finish with the round tool. Gravers can cut almost any conceivable shape and are extremely useful for a hobby guy.


----------



## Z2V

ddickey said:


> An FYI.
> This seller is selling some blanks for a pretty good price I think. I offered $3 and got one.
> https://www.ebay.com/itm/Koncor-Ind...233936?hash=item466e6b42d0:g:QVcAAOSwj99Z78be



I’ve purchased these from him myself, got the last five of his 3/8”. Ships quickly.


----------



## lxcnc

ddickey said:


> An FYI.
> This seller is selling some blanks for a pretty good price I think. I offered $3 and got one.
> https://www.ebay.com/itm/Koncor-Ind...233936?hash=item466e6b42d0:g:QVcAAOSwj99Z78be


Thanks for telling us about this! I just bought 47 of the 5/16” HSS with Cobalt for $1.50 each.


----------



## rac1812

Z2V said:


> rac1812
> I can send a set of Mikey’s tool models up to you if you would be interested in copying them.
> Let me know.
> Welcome to H-M also
> Jeff



Thanks for the offer Jeff ..............  with all my Xmas activities/travel to visit in-laws and out-laws plus the Xmas shipping backlog every where I will pass at this time.  Hoping to have some spare time over the holidays to grind a few.  I now realize that with my Atlas 618,  I can use a 3/8 only if I use the "lantern" tool holder directly.  All my other tool holders are 5/16 and even 1/4 inch..... so I have some scaling down to do....... may need to grind and shrink my fingers.  

I do have a good Harrison 11" in the garage BUT the compound slide is missing......... drawn a blank in finding the C slide in North America and may have to purchase from the UK with some silly shipping charge.  But, I have committed to learn and make mistakes, hopefully smaller ones, using the small Atlas.....one day I will graduate and join the big boys ... the likes of you guys.

My primary interest is the restoration of Canadian Military Pattern WW 2 trucks....known as CMP  circa 1940 to 45 and being able to make some of the odd parts are what drove me to turning.....one day milling.... the parts I need.

I though I would have more free time once retired ..... what a joke!!!!

Very happy to have found this forum and quite content to sit at the back of the room and suck in the knowledge/experience .....

Cheers
Bob C


----------



## Z2V

Bob
If you change your mind just drop me a note and I’ll put you on the list.
Welcome to H-M by the way.
Restoring old WWII trucks sounds fun. I can definitely see the need to being able to make parts that are no longer available.
I had a Craftsman 07301 6x18 up until about 2 months ago, liked that little machine, kinda wishing I had kept it.


----------



## mikey

Hey Bob, if you need to make truck parts then it sounds like getting the Harrison up and running is a priority. I was just visualizing an axle that outweighs your little Altas and thought, "Hmm, I don't think that will work ...". Maybe you can sell the Harrison and Atlas and buy a PM1440?


----------



## rac1812

mikey said:


> Hey Bob, if you need to make truck parts then it sounds like getting the Harrison up and running is a priority. I was just visualizing an axle that outweighs your little Altas and thought, "Hmm, I don't think that will work ...". Maybe you can sell the Harrison and Atlas and buy a PM1440?



Yes they are heavy and grossly overbuilt by today's standards.  So far the big parts have not been a problem it's the smallparts like spring hanger bolts that are no longer available, stock bushings usually need some resizing to fit well, tubular spacers. adapters for fitting modern oil seals to larger holes and brass canvass tie downs shaped like mini capsan winches...... will need to cut out a special profile scrapping tool to achieve the right radius.  The 3 of us working on various restorations have acquired over 34 rolling truck chassis/parts vehicles for spare parts....... and yes I live in a rural area and can hide my mobile warehouse behind the tree line and keep neighbours happy.

More toys makes for a happy Boy!!!!


----------



## DHarris

rac1812 - - - pictures, we need pictures!!


----------



## rac1812

DHarris said:


> rac1812 - - - pictures, we need pictures!!



Would be glad to......
Where do I find the instruction for posting pictures..????


----------



## mikey

Easiest way is to hit the "attach files" button below the active window that you're typing in when you reply. Browse to the location where your jpegs are and upload them to the HM server. They will appear as little icons below your post. You can insert them into your post by positioning the cursor where you want the pic to go and click on either the thumbnail or full sized button. When your pics are inserted and you're done posting, hit the Post reply button and the post will load.


----------



## rac1812

Here is a brief series of pictures....before...during..... first time under its own power,,,, the end.....

Officially known as a Chevrolet 1940.....CMP C15a ( C for Chev, 15 cwt. a for 4 wheel drive)
Has a modern rebuilt 261 in line six........ 4 speed no synchro....2 speed transfer case..... top speed down hill 44 MPH.....

Still have to finish the roof and the cargo box is temporary being a 1943 model...... will reverse engineer a repro box 2B1 in 2018.

Could bore you to death with the mechanics but if anyone is interested I have tons of photos taken over the years for reference purposes.
There are 3 of us grease monkey working form the Hammond Barn....each with our own CMP models....... back field hold about 34 parts vehicles, rolling chassis, etc.

Not bad for a guy who has earned his living being a Human Resources consultant for the feds and now retired.

Bob C


----------



## mikey

Very cool, Bob! What do you plan to do with it? I assume it is off-road capable, right?


----------



## rac1812

mikey said:


> Very cool, Bob! What do you plan to do with it? I assume it is off-road capable, right?



Plans.....?    oh a few parades, military truck shows, already been down to Weare. NH

Very uncomfortable to drive, would need a full heavy load to deflect the springs as is it rides like a buckboard, semi COE gets very hot, so the engine cover needs insulation, found some ceramic felt to replace the asbestos pads.
Yes, it will go anywhere and has pulled out my Massey Ferguson tractor out of many ruts.  

Nice for a pleasant back road drive in the Fall..... cruising at 30 to 35 MPH........ definitely not a highway machine so it gets trailer-ed a lot to out of town events.  On real rough bush roads you get tossed around a lot.

The reality is the truck was design by the Brits, built in Oshawa Ontario, for the typical Canadian soldier of the time..... 20 years old, lean from the depression at 135 lb and about 5'6"......... and I am a modern Canadian 6'2" and 225 lbs......... you do the math!!!!!

If it had suspenders, I could wear it has bush pants.

Bob C


----------



## Z2V

Bob,
I’m so envious, would love to live in a place where I had that kind of room to take on those kind of projects.


----------



## rac1812

Gents and ladies ......must remain politically correct.....

Not sure if is off topic for this thread.....if so please redirect me....... remember I am a newbie hoping to learn......

I would like to learn what grinding wheel is best for HSS steel.....most of the grinding wheels that come with the grinders as OEM are fine for general garage use.  In most cases I have purchased the softer white stone for my wood turning chisels and it works good on HSS.   But there are some series of green and some pink all for a specific purpose........ which is which.  The question of grinder speed..... how relevant & significant to this issue.   More to the point,  metal lathe cutters are now available with carbide tips......... my question is   "  are there any techniques for honing / resharpening the edge of those carbide bits and what wheel or belt could be used.  I just hate throwing away a tip if it can be reused.

IN the past I have used "craftex" hard rubber wheels ( 2 grade course and fine) that did a great job honing the cutting edge BUT had to be installed to run backward away from you....just needed to turn the grinder  180 backward to you and re position the gards..... can't seem t finds them anymore.

Cheers


----------



## mikey

Bob, CBN wheels are intended for grinding HSS and from what we have seen, they do an excellent job of it. They are sold by a number of vendors in the US, like this guy: https://woodturnerswonders.com/collections/cbn-wheels. I suggest you email him to discuss your needs first.

You can also use regular Aluminum Oxide for HSS but I am not an expert on those wheels and will leave that to others.

For carbide, I assume you mean brazed carbide. For that, the green silicone carbide wheels are what you want for that. On the other hand, @JimDawson uses regular gray wheels and maybe he'll chime in. 

For honing HSS, I prefer diamond stones for speed. This is more than adequate for most purposes. However, when you need the absolute best edge on a fine HSS tool, it is hard to beat a fine India stone followed by a polish on a Translucent Arkansas stone. 

For honing carbide, diamond stones are your best bet.


----------



## JimDawson

I heard my name being dropped around here 

Yes, I have a 25 year old Chinese bench grinder that still has the original gray wheels on it.  They are really hard utility wheels.  I grind brazed carbide tool bits on them all the time, you just have to push a bit harder.  It actually grinds pretty fast once it gets red hot.  Also works very well for HSS tool bits.  I also have a Baldor style tool grinder (from Harbor Freight) with green wheels on it.  I do use that for quick touchups and when I need a bit more precision than the bench grinder will do.  I also have a Baldor bench grinder with diamond wheels on it.  That only gets used for fine work.  Sometimes I use my Dremel with a diamond disk for creating chip breakers in brazed carbide tools.  I buy only the finest brazed carbide tools that Harbor Freight sells, about $2 each for the AR-8

If I were doing a lot of HSS tools, I would have a grinder with softer white wheels for final touch up.  I also use my 12 inch disk sander for HHS tools and drill bits.

I have never finish honed any tool bits, never saw a need to do it.


----------



## mikey

JimDawson said:


> I buy only the finest brazed carbide tools that Harbor Freight sells, about $2 each for the AR-8.



Well, as long as they're the finest then okay, Jim! 

Thanks for chiming in. I was concerned about cost and availability of wheels in Canada and I think the common gray wheels would be more easily obtained. I knew you could give us real world experience with them.


----------



## Z2V

jlsmithseven said:


> To all of you grinding these lathe bits, I highly recommend grinding a chip breaker on the top. I was introduced this concept this year and it works amazing. No more tangling up of long stringy chips or any chips building on tool. They just go on top of the chip breaker and fall right down into chip pan. It's made a huge difference for me.
> 
> I've uploaded a picture showing what I mean.
> *In the red outline*, use a stone or grinder to make the end of the tool rounded.
> *In the blue outline*, use the side of a bench grinder to make a slot on top of the tool.
> *The yellow box* is supposed to be a pedestal grinder wheel. Use where the side meets the front edge to do the chip breaker.
> Looking at this image, the cutting tool is like you're looking straight down on it from above.
> 
> View attachment 247736
> 
> 
> 
> 
> 
> 
> 
> 
> 
> [/QUO
> 
> I cut a chip breaker in this tool yesterday. It definitely breaks the chips but I ended up with big balls of real fine chips building up on the tip of the tool. Like steel wool but aluminum
> I think I might have cut a bigger grove than needed, not sure. I’ll grind it flat and try again.
> Leaves a great finish either way.


----------



## mikey

Jeff, I would be interested to hear if you think chip breakers are worth the time to grind them. They work best with materials that have high ductility - aluminum, stainless, some steels. These are the kinds of materials that tend to string rather than form chips. Some HSS tool users swear by them; some don't. 

What say you?


----------



## Z2V

I’m on the fence still. The chips were rolling up on top of the tool but not breaking off. I was concerned about them rolling back under the cutting tip of the tool. 
I want to try different sized groves and also the placement of the grove in relation to the tip and see if  can get the chips to break off without me using my orange stick to knock them off. Grind it flat and try again.


----------



## rac1812

Pardon my lack of experience but........ is it not the purpose of the "back rake" angle to facilitate the chips/curls to move away from the cutting edge??

Would it not be simpler to increase the rake angle for certain more ductile material such as Aluminium, Copper, Brass, etc....

I have noticed some very fine/narrow grooves cut behind and near the cutting edges of replaceable square carbide tips...... but assumed they were needed since the back rake is near zero in most cases.

I actually went crazy with my Xmas shopping and picked up some ready made carbide tips in 1/4 inch size today.......  the best "kwalitee" made in Taiwan for $2.59 CDN.......  curious to see how they will perform.  With the early Boxing day sale also got new, fresh, flat, square edged, 6 and 8 inch green carbide grinding wheels for my two grinders..............  existing grey wheels have already been abused and redressed many time by "others"  using my grinders.......Darn Xmas spirit!!!!!

Bob C


----------



## mikey

Sorry, Bob. I meant to respond to this earlier but I got busy doing stuff for my wife; she doesn't understand that machining stuff is more important than getting the house ready for our annual Christmas party. Not done yet but I wanted to get to this before it cools.

You are correct, in part. One of the functions of back rake is to move the chip away from the edge and increasing back rake will accelerate chip flow but that doesn't affect how the chip breaks; it only affects flow. The same is true for side rake; the more side rake we have, the faster the chip ejects from the cut. The value of this is that it gets the chip out of the cut fast and that removes heat fast. This reduces work hardening and the occurrence of a built up edge so it is a big deal. However, the rake angles don't make a ductile chip break faster by themselves ... it requires a deep enough cut to do that.

A big cut produces a thick chip. As that chip hits the back of the ground part of the tool, it curls. Due to the thickness of the chip it tends to form cracks and with enough flow velocity, the chip breaks. Enough flow velocity is achieved with a high enough feed. Therefore, when you take a big cut at a high enough feed rate with an aluminum turning tool you will see chips instead of strings.

The raised chip breakers on carbide inserts work the same way. If you take a light cut with a carbide tool in aluminum, it will string. Take a big cut fast enough and the big chip hits the elevated chip breaker and the chip breaks. It isn't the elevated chip breaker that does it all; you need enough depth of cut and feed to make it work.

Now, consider what a grooved chip breaker does. This groove is sunken below the top plane of the tool. A ductile chip tends to flow right over the top of it and it has little effect. Well, at least in my experience it does. I have ground many kinds of chip breakers and did not find them of value but that's just me. I found that in order for a chip breaker to work I had to take a big enough cut with a fast enough feed rate ... but was it the chip breaker or the cutting conditions that caused the chip to break? I suspect it is the latter. In my view, a chip breaker has to alter the direction of flow in order for it to influence the chip so it has to be raised, not sunken below the plane of the tool.

So, this whole chip flow stuff gets a bit complicated, and the tool's geometry is only one part of it. The user has to know how to use the tool to best effect.

Oh, as for softer materials like brass and copper, a raked tool will work but it can dig in if the tool is not sharp. I know for sure that a Square tool will cut brass just fine but I will use a zero rake tool for brass in preference because of the finish it produces. A flat topped tool for brass will take a big cut and leave a beautiful finish, and I believe this has to do with how the chips break with that tool. Try a square tool and a flat top tool in brass and look at the chips. Compare the finish and the accuracy of the cut and you'll see the differences.

Anyway, this is all just my opinion on this stuff. I hope it hasn't confused you.


----------



## ttabbal

I know there are some grooving tools I can buy, but just for my own education... 

I have a part in mind that needs o-ring grooves. Let's say it's for a -223. If I want to make an HSS tool to cut those on the OD, what does it look like? 

My first thought is that it looks much like a parting blade. Wider at the top, tapering toward the bottom on the front and sides. Cutting edge the width of the groove or smaller, straight to make a flat bottom in the groove. Only sticking out as far as needed. Seems like a parting blade would work the more I think about it. But one could grind a similar profile into an HSS blank. 

Material I have in mind is 6061 aluminum.


----------



## Bob Korves

ttabbal said:


> I know there are some grooving tools I can buy, but just for my own education...
> 
> I have a part in mind that needs o-ring grooves. Let's say it's for a -223. If I want to make an HSS tool to cut those on the OD, what does it look like?
> 
> My first thought is that it looks much like a parting blade. Wider at the top, tapering toward the bottom on the front and sides. Cutting edge the width of the groove or smaller, straight to make a flat bottom in the groove. Only sticking out as far as needed. Seems like a parting blade would work the more I think about it. But one could grind a similar profile into an HSS blank.
> 
> Material I have in mind is 6061 aluminum.


First you need to know what size grooves to make.  They are critical to good results.  Here's one:
http://www.qualityseals.com/pdfs/groovedesignandoringinstallation.pdf


----------



## mikey

ttabbal said:


> I know there are some grooving tools I can buy, but just for my own education...
> 
> I have a part in mind that needs o-ring grooves. Let's say it's for a -223. If I want to make an HSS tool to cut those on the OD, what does it look like?
> 
> My first thought is that it looks much like a parting blade. Wider at the top, tapering toward the bottom on the front and sides. Cutting edge the width of the groove or smaller, straight to make a flat bottom in the groove. Only sticking out as far as needed. Seems like a parting blade would work the more I think about it. But one could grind a similar profile into an HSS blank.
> 
> Material I have in mind is 6061 aluminum.



You are right - an O-ring tool is just a grooving tool that is essentially the same as a parting tool. When I need an O-ring groove, I use a parting tool that is narrower than the required groove and cut it to the desired dimension. I don't bother grinding these tools - a P-type blade works as well or better. For internal O-rings, I use a carbide grooving tool that looks like a parting tool sticking out the side.


----------



## ttabbal

Thanks! I thought I might be missing something with the tool form. 

So looking at the document Bob posted and the size charts, the example I used of -223... 

It's a 0.139 width. So for a static application, I want a depth of 0.111-0.115 and a width of 0.185. With a slight radius on the corners.


----------



## mikey

Actual O-ring groove tools look like a parting tool but with a small inward bevel at the corners, like this:





Personally, I don't bother altering my parting tool but you could.


----------



## Sackett

Soooooo,whats happening with the new cutting tools n models??? Who's had smashing sucess,,,who not so much?I've got some ceramic belts for my Horrible Fright sander,,,not sure its worth a glass platen,,,but gonna order a couple anyway.   Inquireing minds wanna know


----------



## westerner

Mikey- Brino led me to this thread. What a GREAT addition to this already fantastic site! I have read the entire thread over the past few days, taken copious notes, and am shopping belt grinders, and building rests in my mind.
  With your fine examples in both practice AND theory, I am confident I will be able to significantly improve my skills, and my projects. Some of your principles I innately understood, others I understood after digesting your theory. Many, many thanks to you, and those that have shared their experiences. 
  One question remains- did you ever make your living in this industry? If not, your dedication to improve, your powers of observation, and your refusal to settle for "close enough" are truly inspiring to this noob. 
  Thank you for your efforts in ANY case!


----------



## mikey

westerner said:


> Mikey- Brino led me to this thread. What a GREAT addition to this already fantastic site! I have read the entire thread over the past few days, taken copious notes, and am shopping belt grinders, and building rests in my mind.
> With your fine examples in both practice AND theory, I am confident I will be able to significantly improve my skills, and my projects. Some of your principles I innately understood, others I understood after digesting your theory. Many, many thanks to you, and those that have shared their experiences.
> One question remains- did you ever make your living in this industry? If not, your dedication to improve, your powers of observation, and your refusal to settle for "close enough" are truly inspiring to this noob.
> Thank you for your efforts in ANY case!



Wow, thank you, and thanks also to @brino for his support. This thread has grown beyond my expectations, primarily because of the great members who have participated in it and they have my thanks, as well. 

While I tried to give enough information here to reproduce my personal tools, that was never the point. The point is to take what you learn here and *go further* to create tools that work better for you on your own lathes. We are seeing the beginning for a lot of the guys in this thread but it isn't the end. One day, they will wonder if they can tweak their geometry a bit here, a little there and that is where the real growth begins. 

My privilege has been to be here at the start of that.

So, Jim, jump in and PM @Z2V to get the models in your hands. Give it a go and share your experiences with us. If I can help you, I will. 

Mike


----------



## rac1812

mikey said:


> Wow, thank you, and thanks also to @brino for his support. This thread has grown beyond my expectations, primarily because of the great members who have participated in it and they have my thanks, as well.
> 
> While I tried to give enough information here to reproduce my personal tools, that was never the point. The point is to take what you learn here and *go further* to create tools that work better for you on your own lathes. We are seeing the beginning for a lot of the guys in this thread but it isn't the end. One day, they will wonder if they can tweak their geometry a bit here, a little there and that is where the real growth begins.
> 
> My privilege has been to be here at the start of that.
> 
> So, Jim, jump in and PM @Z2V to get the models in your hands. Give it a go and share your experiences with us. If I can help you, I will.
> 
> Mike



This is where the information and the reality hits the road.

I am only playing with  5/16 "key stock" and wish to report the following.

I NEED A BIGGER BELT GRINDER ........ I am using a 1x42 belt with a 1/3 hp....model from Lee Valley.   As expected it is slow, you can actually cause the motor to go down to its starting mode/windings and the work table is a ***** to adjust and keep its adjustment.

The other major problem is that using zirconium blue belts the small piece of tape seems to be affected by heat and/or age and comes apart very very easily.   In fact a new belt under tension for a few days, not even running, released on its own.  I know I have bought new ones at Xmas but got them mixed with some of the old but new stock.  I intend to experiment with crazy glue or fresh cuts strips of Gorilla tape.

Take me about 45 minutes to cut one bit, with dips in a water tub near by.  Finally used the more expensive "Microfinish" plastic backed belt also from Lee Valley and that worked much better and belt held up and shows very little wear.  Finally obtained a good left hand tool to my liking.
Finished the sharp edge with a hand held diamond honing tool that carefully gave me a nice thin line of light reflection.

Now I have not used it yet and for the first few ones I cheated and worked on 12 in long pieces of key stock.  I is far more tolerant of heat build up with the extra mass.

Concerns....... if my set up is under powered the HSS bits and the special extra hard one "REX". (which I got for experimenting for bit to be used on the boring bars of my wood lathe)  will be very time consuming.

some solutions I am considering short term....

Get my wooden stool from the barn so I can get comfortable and be more patient.

Try doing the rough cuts on the 6 inch General grinder that spins at 1750 ( primarily for the wood lathe tools).... it has a white Alum oxide and a green HSS wheel......than finish the surfaces flat with the belt grinder.

Also have a 8 inch 3/4 grinder at the barn that I may transplant to my basement shop as it would create less of an ark in the rough grinding with less correction for the belt grinder.  I has both a fine grey and fine green HSS stone.  That grinder I usually do not share in order to keep my stones well dressed flat.   We have another 6 inch at the barn for gouging steel and I have given up dressing the center grooves done by others heavier handed operators.

Last short term solution....... I have purchased a separate grinding stand from Lee Valley that will allow me finer adjustment with the existing belt grinder.....much more steady and more likely to keep its setting when in use.

But if I am going to get serious about this......I NEED A BIGGER BELT GRINDER....   fortunately there are a number of styles and models for the DIY available on the web either as plans or heavily documented with Photos and I am good at marrying the best features of various designs.  Main issue is sourcing parts such as wheels,  belts, etc.

Any comments or recommendations are all welcomed.  DO you have a favorite design or favorite features that should be considered??

Meanwhile, except for Mikey getting Sun burned, try to stay warm.

Bob C


----------



## ttabbal

Well, I also blame Mikey for my belt grinder build.  

I built one of these. 

http://dcknives.blogspot.com/p/2-x-72-belt-grinder.html
http://dcknives.blogspot.com/p/bg272-adjustable-tool-rest.html?m=1

You can get the parts cheaply if you shop for a while. A free treadmill can supply the motor, or you can get a 3 phase and use a VFD for speed control. If you have a lathe, wheels are easy enough to make, the glass-filled nylon ones I got were $70 on ebay from Oregon Blade Maker. 

Using a ceramic 36 grit belt at about 5000 sfpm, 3/8" keystock takes about 5 seconds to grind a largish flat. Think the one from Mikey's threading tools. The grind area gets hot, but the bit itself, cut about 4" long, doesn't get bad. The grinder does not appear to notice I'm grinding on it. Just keeps humming away.  I picked up a pack of a few different grit belts to put a better finish on them. The 36 grit is pretty rough, as you would expect. I haven't tried HSS yet. I need a face shield.  

Motor is a Marathon N437. 1750 RPM, 3 phase 220V, 2HP. Run from a VFD. I had it at 100Hz for the test above. I was going to use a treadmill, but lucked into someone selling NOS motors.


----------



## rac1812

Some of the ideas are starting to gel.......

I am thinking of mounting the 2 HP s.p. 220 under the table with stepped sheave and drive shaft on pillow blocks above.
Hoping to recycle an existing steel legged table with a 2 in. maple top..... keeping depth of the work area to reasonable size and having less dust get into the motor.  I may buy ready made wheels with the pressed bearings.

Love the information you included.   when I build jigs at the barn we always use 2" and 2 1/2 " in. trailer stock square tubing with 1/4 in. thick walls the extra weight/mass sometimes helps and there are no weld seam inside to grind off.

I would like to make the work area...... adjustable tool rest... to be made out of some thick steel plate and have a groove machined/cut into it similar to a table saw so  can build various grinding jigs. 

*********How critical is a variable speed motor?  when would you need to slow down or speed up?  Leaning towards the step pulleys, which are cheaper, and already have a spare 2 hp motor.

*********Would there be an advantage to having the grinding tool rest attached to the table instead of the grinder body itself?

********* are there any situation where reversing the direction of the belt would be of any use???

Getting stuff to Canada is not an issue as I maintain a UPS box just across the border..... save on shipping within continental USA,,,, and 50% of the time you are not asked to pay Canadian sales tax........ no other duties for personal use.

Better start checking out my steel stock .......... I do have some 1/2 inch Duralum but not set up to weld  aluminium.

....and I like the reminder to get a proper face shield and maintaining the plastic shield clean.  All the ones I have are hard to see through and therefore get covered with grinding dust sitting on the bench/wall unused!!!!!!.

Thanks for your help.

Bob C


----------



## ttabbal

My thinking on speed changes is that I only expect to use a few. Ceramic belts like high speeds, while finer grit AO belts will want to be a bit lower. And perhaps slowing when I'm getting close to the size I'm aiming for. I don't see a problem with step pulleys if you don't mind changing them once in a while. And if you already have a good sized motor, might as well use it. 

I don't see any big pros or cons for the rest being attached to the machine vs the bench. 

I haven't come up with any reason for reversing either, unless you wired it wrong I guess. Same thing with versions that allow for horizontal operation. 

For the work table I have considered finding a cheap/free/broken benchtop sander or similar to get the table from. For now I think the flat plate will get it done though. 

If you decide to build one, please share pics and such. It's always interesting to see other people's takes on the basic design.


----------



## mikey

Hey Bob, the best option is to build or buy a decent belt sander, at least in my opinion. You can certainly grind a good tool on a bench grinder if that is cheaper or more desirable for you. I suspect more tools are ground on a bench grinder than any other kind of tool in the world. A belt sander is faster, cooler, easier to control the tool on and easier to re-grind tools on but it is not the only option.

Now, with that said, if I were going to have a new belt sander it would be a 2x72 like @ttabbal and the other guys have. It would be the ideal tool grinder but more importantly, it would be the most useful for general fabrication around your property. These grinders are simple to fabricate for most hobby machinists and the wheels can be obtained fairly easily on ebay. Very importantly, the belts are widely available in just about any grit or quality level you need. I don't have one (yet) but I recognize their utility and speed. When I do build one the "blame" will definitely go the other way!

A belt sander has to run at decent speeds to actually grind metal. Burr King says this is around 8,000 SFM. Below that, it is considered a belt sander, not a grinder. I've used a big Burr King and it definitely eats metal fast. So, you need a motor that has decent power, 1.5 - 2.0 HP, that is at least 3500 rpm in direct drive or pulleys that allow it to reach grinding speeds. A 3-phase motor with VFD, a decent DC motor or a good old AC motor at 3450 rpm with a pulley system will all get you into the speed range you need. 

Variable speed is useful when you go to finer belts. Finishing grits work better when you slow down the belt. For shaping a tool bit, the coarser grits work better at higher speeds.

I don't think a reversible motor is useful for tool grinding but I know the knife sharpening guys run it in reverse to sharpen knives.

As for the tool rest, I think it best to have it as an attachment that slides into place alongside the belt. This allows you to slide the rest away to change belts, then slide it back into place without losing the table angle. The table should allow you to easily adjust angles and mine would have an indexing template for that purpose. The table should have support ears on both sides of the belt to allow you to support the bit as you grind rake angles. 

Your platen should be very solid. The basic designs on most 2x72 grinders is fine but in my opinion you should incorporate a glass platen to keep it flat. 

Hope that helps you think through your project. I've certainly thought about it and all these guys dangling their carrots in front of me is bugging me. If I didn't already have a belt sander that works well I'm sure I would have moved sooner. When I do build one, it will be well thought out and functional but it is going to be tough to beat the ones our guys have already built.


----------



## rac1812

Response to Jeff

Can you send me some close up of the workings of your tensioner device and belt tracking.  In your case which wheel is the domed wheel.... the larger one on the motor or the smaller adjustable tracking/tensioning wheel???

.....for everybody else.....
There is only one basic design ....... but many different ways of getting there.  I am trying to learn as much as possible about the different build/design technics ........ will only do one once..so trying to learn from all the postings on Epay and Ewe/tube.

No matter the outcome I will document with pictures for the forum.

I am considering building up the main body from flat plates instead of trailer tubing in order to eliminate the natural slop found in trailer tubing.  I have seen a HD design on Epay that has welded flat plates creating a very tight fitting tube for a solid 2 inch steel bar both for the wheel platen support and for the tool rest.  I am leaning towards a design that will give me precise settings.   Being still at the paper design stage anything can be added or removed with an eraser.

Any source for the corning ware platen strip I will eventually need ?

Thanks

Bob C


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## mikey

Check here for a platen liner, Bob: http://usaknifemaker.com/catalogsearch/result/?q=platen+liner


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## Z2V

Sure Bob
Actually the tracking/tension wheel and the drive wheel are both domed. 
The glass I got here for $20 shipped.  https://usaknifemaker.com/catalogsearch/result/?q=Glass+platen
Here’s a closer look at the tension wheel.


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## rac1812

Thanks guys.

...and the knife maker has Micarta/phenolic material we need to replicate the charging panels used for powering/connecting hard wires for radio installations and workhorse charging systems........ 2 birds with one stone.

Cheers


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## rac1812

Sorry guys I am getting confused with the "conversation" I am having with Jeff and the information/picture sent by ttabbal

Looking at the green machine from ttabbal..... I was wondering how he accomplished his build of the tensioner on his particular design.

Jeff is supplying me with a set of wheels so I am off and rolling...... my design is still fluid and still considering various options.


----------



## ttabbal

The drawings show how it works, there is a page with a detail view of just the tracking pillar. 

The short version is that I marked the square tube with the angle, then cut that line on a bandsaw. 
Then the short side is cut off, leaving a U shape part. 
Drill a hole in the long side for the tracking wheel axle. 
Drill a smaller hole all the way through both sides for the hinge bolt. 

Then the pillar tube has a through hole that is larger on one side, large enough to fit the bolt head into from the tracking hinge. 

There is an adjustment bolt going through the tube that pushes on the bolt head for the tracking wheel. So it can sit inside the pillar, or get pushed out by the bolt.

If you have questions, let me know.


----------



## rac1812

Thanks Dan

I think I have reached "information overload" as I  could not remember that I had in fact looked at and read you attachments.

....and after watching Utube and seen tons of overbuilt machines I will lean towards the KISS formula.... well built, solid and dependable without breaking the bank or being so bulky I can't move it around.

Thanks for all your patience and assistance.

Bob C


----------



## rac1812

Catch 22.........  would be nice to have the grinder to make the parts I need for making the grinder.

Leaning towards the 2 inch 1/4 wall that I have in stock..... and follow Dan's design information.

Concerned with the removal of the weld seam inside a 10 inch long tube.  That will be my fist test.

Will weld a few nuts and see how tight I can get a bar to fit with out rattling inside the tube.

solid bar in 1 1/2 by 36 inches......... 12 dollars difference between steel and aluminum...... steel allows me to weld....Alum. means drilling and tapping.

Back up plan is to build one with two 3/16 side plates and 1 1/2 solid steel spacers giving me a more square tube for inserting the 1 1/2 solid bar.

Stay tuned.


----------



## ttabbal

Unless your tubes are very tight fitting, don't worry about the weld seam. Put the holes/nuts for the locking bolts on that side. Then the off square issue goes away. 

The slight slop is a non issue. The only exception is the tracking pillar. You have to shim that a little bit to keep tracking straight. The two arms toward the front are held with the bolts from the side and don't move once those are tightened. 

I used all steel per the plans. I wouldn't use aluminum in part because I don't like threads in aluminum. I'm just not nice enough to fasteners, even when I am trying.


----------



## rac1812

Finally positive results....

Found a 12 inch long piece of 2 1/2 thick wall ( 1/4 in.) and tried to remove the weld seam....... air die grinder can only do about 2 inches.  Then I remembered my old Craftsman "commercial" electric die grinder....... as not been used since I was porting 455 Pontiac engines in the mid 80s...  and it still worked.  Had to clean all the grinding dust from the casing and oil it a bit but it gave me a 7 inch reach inside the tubing.  Takes time but worked great.  The insert tube 3/16 thick walled 2 inch tube fitted quite nicely......... some looseness but not much.

 I drilled a  2x12 in. square  tube at 2 in. and 6 in. and Mig welded two fine thread 3/8 bolts.

Only had to snugged the two bolts and the insert tube is firmly in place.....and I mean real solid.

Now to do the same for the second tube and the vertical tube for the idler wheel.

After all this grinding, in the cut off stock pile I found a 4 foot section of 2 1/2 trailer receiver tube THAT HAS NO INTERNAL SEAM.....but the fit with a two inch insert is somewhat looser fitting......  will know more once the bolt/nuts are installed.

I have turned the corner and committed to a tube construction.  For me steel is so much easier than aluminum.
Will be plasma cutting the Base plate from spare 3/16 stock and getting ready to fit a jack shaft for the drive pulley.

Bob C.


----------



## mikey

Anxious to see your grinder, Bob!


----------



## Z2V

Bob, remember that we like pics. Looking forward to seeing what you come up with!


----------



## mikey

Was cruising ebay and saw a listing for 50 Chinese 3/8" HSS (M2?) for $69.00 with free shipping: https://www.ebay.com/itm/50pcs-3-8-...480439?hash=item486dc82c77:g:ITMAAOSwRLZUCgJb

Comes out to about $1.28/bit. This is the kind of bit I use to experiment with and I usually only use my high quality bits for keeper designs that I've worked out the geometry on. I think for you guys who are just learning to grind tools, this is a very good deal. Save your premium quality bits for your best tools and use these for daily drivers - they should be fine for most of us.


----------



## ttabbal

Thanks for the info mikey! I ordered some, should keep me going for a while. I'm already planning on firing up that grinder you made me build for some practice runs. Thanks for that too, it was a fun project I'm going to get a lot of use out of.


----------



## mikey

I ordered some, too. I tend to give bits away to new guys that stumble into my shop and I was running low on Chinese bits so this was a good time to re-supply. This is a very good deal, almost as good as the time I "won" a box of 20 high quality ETM M2 bits for less than $20.00, shipped!

By the way, the price for these bits just dropped $5.00 and they are now $64.00, shipped, for 50 3/8" HSS bits!



ttabbal said:


> I'm already planning on firing up that grinder you made me build ...



I need to get off my butt and build me one so I can blame you guys, too! I especially want to figure out how to make an indexable tool rest for one of these things. If you 2x72 guys come up with a good rest design, please share it.


----------



## Z2V

That’s a great deal on the tool bits. I’d like to get some but I don’t think I need 50 of them. If one of you guys is in the same boat and would like to split a 50 ct lot let me know.


----------



## ttabbal

Z2V said:


> That’s a great deal on the tool bits. I’d like to get some but I don’t think I need 50 of them. If one of you guys is in the same boat and would like to split a 50 ct lot let me know.



I doubt I actually need 50 of them. I'd be willing to split my batch up when it gets here. I bet a fair number would fit in a small flat rate box.


----------



## rac1812

Got some work done on the grinder in between snowblowing.

Did a preliminary mock up.   Found a steel table in the attic of the barn that was used for a Delta cast iron jigsaw.  It will reduce the floor foot print as it is narrower than the one I had planned on using.  Motor will be mounted higher for a shorter belt and set up on a swing shelf using the weight of the motor to tighten the belt.  Safety switch in front.  Managed to rewire the motor to turn CW as required by the design.  Will be using 4 step pulleys for variable speed.

The two springs on the tension arm are not yet fastened ........will need the belts to test the tension required.

I used whatever steel we had on hand..... tubing is thick wall (1/4 in.) trailer receiver (2 1/2) inserts are 2 in. thick wall as well.  The whole assembly will be welded to a 3/16 plate and bolted through the wooden top and steel table top.... It ain't gonna move.

Most of the odds and ends should be sitting at the UPS store by the end of this week for pickup.

Working on a work platen/table  that will be pivoting to adjust the grinding angle rather than rely entirely on the adjustment of the D plate.

Considering building an angle iron frame work with casters for mobility and to raise the working surface a few inches for my 6'2" frame.

Comments, questions, suggestions welcome.

Thanks everyone for the help, inspiration and parts.

Cheers


----------



## Z2V

Lookin good Bob!


----------



## mikey

Doing good, Bob!


----------



## hdskip

Maybe someone with a printer could print up some examples to be used for guides or patterns or what ever you'd want to call them. Just a thought from and oldster who only knows a little about printers.
   Trust me I can't believe I'd ever say something like this about 3D printers .LOL


----------



## benmychree

tweinke said:


> I think that would be an awesome idea. Possibly grind a standard LH, RH, threading tool, and ??? I for one would be very interested in actually being able to touch a tool that has the potential to work instead of guessing from pictures.


Add in a round nose tool


----------



## benmychree

dlane said:


> a shear tool , acme thread,


If you have a surface or T&C grinder, look for a Clark threading tool sharpening block, they make acme and 60 degree tools with perfect angles.  I found on  e bay.


----------



## rac1812

Round nose tool.....

Years ago when wood turning I bought a home made scraper....the tip was a 5/16 HSS bit..... rounded tip that needed sharpening.  The tool came with a 1/4 in pink 6 inch grinding wheel.   To sharpen you held the tool against the tool rest that about 15 degree then lightly pushed the tip over the rounded edge of the wheel.  The tool did not move just angled right than left........ gave a very sharp edge even curve both side.  I think it would work for a HSS round nose but would need a top relief cut at 15 degrees as well as per Mickey's teaching.

Only problem is I can't find that famous 1/4 pink wheel in all my junk.... I know I have but where?????

Working on the wooden steel table top for the grinder......drilled all my wood and top steel plate for 3/8 BUT the existing holes in the steel top table are 5/16....crap!!!  more work tomorrow.....Friday I get my D plate and belts......

Comments on the pink wheel please.

Bob C
PS..... and it is snowing like h*** but not as bad as Upper NY state.


----------



## mikey

benmychree said:


> Add in a round nose tool



Agreed. We discussed it briefly in post 435. Very useful to have.


----------



## benmychree

Those pink wheels are premium, cool cutting and long lasting; dress and shape with a boron carbide dressing stick.


----------



## rac1812

Mikey.....a quick question...... was reading a number of old post and memorizing your postings...... There is a mention of a wax lubricant applied to the grinding belts......  what is it exactly......  any need for lub on the glass plateen side...?  concerned with the belts slipping under grinding pressure.


Bob C.


----------



## mikey

rac1812 said:


> Mikey.....a quick question...... was reading a number of old post and memorizing your postings...... There is a mention of a wax lubricant applied to the grinding belts......  what is it exactly......  any need for lub on the glass plateen side...?  concerned with the belts slipping under grinding pressure.
> 
> 
> Bob C.



I mean this stuff: https://www.amazon.ca/Trend-TRENDIW...518205786&sr=8-1&keywords=wax+stick+lubricant

It is applied to the belt as it is running. You only need a little - push it lightly into the belt for a few seconds. You do NOT apply it to the platen side of the belt, only on the abrasive side. It really helps the belt to cut cooler, faster and extends belt life. You can use it as a lube for drilling, tapping and to lube your hacksaw and bandsaw blades. One stick will last a long, long time.


----------



## rac1812

Just did a quick search on the web and found it listed right next to K-Y jelly....Intimate lubricant.......  You would not want to get those two mixed up.


----------



## mikey

Yeah, but it might improve the rigidity of your tools!


----------



## rac1812

One quicky.......????

How much pressure should the idler wheel exert on the belt....enough to track but not enough to break it........  on car fan belt we go by deflection over a set length of the belt........

Lots of fiddling today to square up the tube portion against the jack shaft at the back ....have not hung the motor underneath but I am satisfied by turning the drive belt by hand that it is reasonably lined up but concerned that the idler pulley is not exerting enough pressure on the belt.

I have a gas strut that borders on too long and dual springs that I think are too soft.

Now the jack shaft step pulley did not come with the grub screws.....( cheap Ba*****)  ......
........and the grub I got is imperial  and the pulley from China is metric.....Arrrghhh!!!

Well we decided to call it quits..... roads are getting bad with freezing rain so we shut it down.

Cheers......

PS.... you know it is cold when you need to flash the floor drill chuck with the propane torch to loosen up the lub in the chuck so it will turn easier by hand......... the drill happens to be farthest away from Lucifer  which was roaring on hard wood and dripping engine oil.


----------



## Aaron_W

Ok, after months of anticipation I've turned my first bits. 

I started off with Mikey's square tool. I messed up my first attempt by grinding the top angle in the wrong direction, but luckily I bought the special beginners blanks that come with two ends, and think I got it right on my second attempt. 

The top angle was my biggest challenge, it is an awkward angle on the grinder. First attempt I got mixed up and ground from the left putting the slope in the wrong direction.


Mikey your instructions worked great. I printed them out and just followed along step by step.

I just used a small piece of scrap 2x4 to push the bit against the wheel. That worked, but I think I'll cut it down into a 2x2 or 1x2 for the future. I was really surprised at how fast the grinder removed the metal. I think it only took me about 10 minutes to complete both the mistake and its replacement.  


I'll need additional practice to get comfortable, but I think my first (ahem, second) attempt created a functional tool so I'm pretty happy. I fully expected to trash 4 or 5 blanks figuring stuff out. Helps to have good instructions.


----------



## mikey

Congratulations, Aaron! That looks good for your very "second" grind. Trust me, I know it isn't easy the first time but you done good! In time, tool grinding will be very easy for you.

How does the tool cut?


----------



## Aaron_W

I've been working outside getting the work bench built so I could mount the grinder, but that left a pile of tools in front of the indoor workbench and the lathe. I'll be getting the shop cleaned up tomorrow and try it out. I will let you know how that turns out.


----------



## Z2V

Looking good Aaron. Did you end up going with a 8” bench grinder or a belt grinder? Your building a new grinding bench, show it off, we like looking at pics!!


----------



## Aaron_W

Z2V said:


> Looking good Aaron. Did you end up going with a 8” bench grinder or a belt grinder? Your building a new grinding bench, show it off, we like looking at pics!!



Yep, I went with the 8" Rikon 1hp grinder that several suggested. That is a nice grinder, smooth, fairly quiet and it took the metal right off. Like most grinders the tool rests leave something to be desired. Would be nice to have something larger, particularly for grinding that top angle but they are at least stable and will work until I can make something better.


I'm building a work bench, but withholding photos until it is finished. I did post the detachable mount I made for the grinder though, which is attached to the new bench.

https://www.hobby-machinist.com/threads/quick-release-grinder-mount.67170/


----------



## Z2V

I somehow missed the thread you started there. Good idea on the quick mount and that’s a really nice looking grinder as well.


----------



## mikey

A good rest makes a huge difference in how your tool grinding goes. Jeff made one that he showed earlier in this thread and others have made similar designs. I have this one: http://accu-finish.com/product/grind-r-table. I have two bases and one table. It doesn't see much use but when I did use it, I switched the table from one base to the other to use the two grits I have mounted. Not suggesting you buy one but it is an example of a design I know to work well, at least the table part of it.


----------



## Aaron_W

Well it cuts, I didn't have anything in particular to work on so just made some test cuts and turned about 1 1/2" of 1/4" aluminum into 1/8" aluminum. Cut nice though.

Also faced and turned a piece of that cold rolled steel. not pleasant stuff to work with. 1" bar cut with a hack saw. That has also gone a long way towards convining me of a need for a band saw....


The tool rest on the grinder will work for now, I want to use it enough so that I really have an idea of what will work for me. I imagine something like that Accurest is what I'll want though, I've seen another similar to that that seems to be popular. I'd really like to make my own though. It doesn't seem like it would be that hard to make something functional.


----------



## rac1812

Well 90% of my belt grinder is finished, wired and running fine....... now working on a adjustable work table.  There is no stalling that 2 HP motor now.

will first build a solid flat table from 1/4 inch steel.....and that will help me grind the parts for the adjustable table.  I prefer to tilt my work table to adjusting the D plate.  Platen running on steel now glass to be installed later......also seriously considering installing a goose neck LED lamp aimed directly at the cutting area.

Meanwhile, nursing cold I worked on the 1x42 belt grinder in the basement...... I have a greater appreciation for a solid work surface as thet able should not move when leaning on it.  I now have the largest collection of busted belt...... everyone went.....from the 2 or 3 yeat old belts to the recently purchased 3 months ago.  By the way my new 2 inch belts stored in the barn are inside air tight ammo boxes with dis-secant bags in the bottom.  Using only one AO as test for now.  I have gotten real good at telling when the belt is about to break loose and duck fast.  All of them let go at the tape joint...... one actually let go before I could turn the motor on.  I searched Utube and tried different method for reglueing including my dear wife's clothe iron for heat process with no success....... iron on patches work the best for a few minutes until the heat builds up and FLAP!!!!

Also learned the lesson of wearing loves......between the heat and the slap from the broken belt, I now use the light weight, part cotton part leather, tight fitting gloves sold for mechanics..... they protect but provide sufficient tactile feeling.

Part of the reason for so many broken belts is that I switch from key stock to HSS....... which is really toooo hard to work with the small 1x42.  Also down sized from 3/8 key stock to 5/16 HSS and..... Gezz it is small ..... 1/4 HSS....

I will need to get my courage up to shove a tinny 1/4 cobalt bit into the 2 in. grinder with my clumsy fingers....... seems to me that wooden blocks of matching thickness will be of help rather than one size fits all.  I find cutting the "rake" angle dangle is the hardest as you are working past the belt on the sides and the table I was using is too short.......... or maybe tilting the D plate might make it easier........(problem solving as I write)...

To be reasonable, I need to test myself with key stock again on the big belt.... then gradually work down to the smaller key stock  size..... and then and only then try my hand at HSS and hard cobalt squares.

Will have pictures for " show and tell " later this week.

Bob C.
   .


----------



## mikey

Aaron_W said:


> Well it cuts, I didn't have anything in particular to work on so just made some test cuts and turned about 1 1/2" of 1/4" aluminum into 1/8" aluminum. Cut nice though.
> 
> Also faced and turned a piece of that cold rolled steel. not pleasant stuff to work with. 1" bar cut with a hack saw. That has also gone a long way towards convining me of a need for a band saw....
> 
> 
> The tool rest on the grinder will work for now, I want to use it enough so that I really have an idea of what will work for me. I imagine something like that Accurest is what I'll want though, I've seen another similar to that that seems to be popular. I'd really like to make my own though. It doesn't seem like it would be that hard to make something functional.



Keep us posted on how your rest turns out, Aaron. This tool grinding thing takes time but you'll get it down quickly. I hope your tools open up all the potential your lathe holds for you.


----------



## mikey

Hey Bob, your post reminded me of the day I ground the tool in this thread: https://www.hobby-machinist.com/threads/how-to-grind-a-hss-turning-tool.52581/

Just as I was almost finished the belt snapped and scared the crap out of me! It took a bit of courage to get my hands next to another belt from the same lot to finish it, I can tell you that. Old belts will let go with very little warning. All you get is a little noise then BAM! Buy some new belts and grind with confidence. They will generally will hold up for a year or so before the tape gets brittle.


----------



## tweinke

Amazing that this thread is still going! Seems that some of us kind of got the cart before the horse in respect to grinding tools vs what to grind with. I'm not saying this is bad by any means. Still working on my belt grinder, so far so good. Need to get a motor and grinding rest made. The tool and cutter grinder I had bought never happened. The guy came and refunded my money and apologized  before I could pick it up, Dang it! I'm thinking the belt grinder will probably be a better choice due to lack of space and usefulness.


----------



## Aaron_W

tweinke said:


> Amazing that this thread is still going! Seems that some of us kind of got the cart before the horse in respect to grinding tools vs what to grind with. I'm not saying this is bad by any means. Still working on my belt grinder, so far so good. Need to get a motor and grinding rest made. The tool and cutter grinder I had bought never happened. The guy came and refunded my money and apologized  before I could pick it up, Dang it! I'm thinking the belt grinder will probably be a better choice due to lack of space and usefulness.



I get the feeling that is just the nature of the hobby. 

I haven't been doing this long but I think it goes something like this:


I want a lathe

I need a grinder to sharpen the bits for the lathe

I'm tired of cutting metal with a hacksaw, I need a band saw

This isn't round but I'd like to put some holes in it, I need a drill press

I'd like to put some holes in this thing, and I need them perfect, I need a mill

The grinder has crummy tool rests, I need better tool rests

This guy says a belt sander works better than a grinder, I need a belt sander

I need a bigger lathe

I need a bigger shop


----------



## mikey

Aaron, the slippery slope is bottomless - it never ends. The only difference between you and the rest of us is that we've slid waaay past where you are now. Have fun and enjoy the journey!


----------



## DHarris

I wish it was just a "slippery slope" - so far I feel like it's much closer to an Olympic  bobsled run!!!!


----------



## rac1812

As long as you enjoy the ride........ and give yourself a Gold Medal.

got some small "gas struts" for my grinder and working feverishly at building a tilt table for the grinder.  Looking forward to getting it up and
 "operational" than I can start the next late Winter project of building a "rotisserie" to help reverse engineer a 1940 cargo box for my old Chev.

Bob C


----------



## Z2V

Hi Bob
Good to hear it’s coming together. Are you finally getting a break from the snow and crazy cold temps?


----------



## Brento

I need to go back through this thread so i can find the examples and instructions.


----------



## Z2V

The meat and potatoes starts on page four.


----------



## DHarris

Brento, somewhere in the one of the posts is a MS word document I put together of all of Mikey's tutorials on the actual grinding and reasoning for each step.  It's 19 pages long on 8.5x11 paper!!  Mikey should have been a professor - his explanations are great!


----------



## rac1812

I have taken the long route and been copying and emailing myself the text which I later open and save as precious information.  Mikey's style is so much superior to all the old school books (circa 1890) I have collected/read that are so hard to understand.

A number of hobby forums I belong to have a lot of similar "priceless information" which is worth every effort to preserve as most of us are on the slippery down side of our lives.  I have a collection of photos taken of various military restoration projects which will be passed on as digital legacy to a fellow collectors to insure they are shared in the years to come..... it may fall under intellectual property..... but so is the story of Adam and Eve.


----------



## dbq49

I did not read any where in this thread what kind of tool holder will be used.  A quick change holder or a lantern holder.  I have read some want to use a belt sander, bench grinder but no mention of a tool grinder.   Then what about the grinding stones on these grinders.  And I did not read anything about using a wet stone to polish the edge, a diamond stick to polish, what about a water stone?  When I was teaching machining, we used a 2x2 wood stick shaped to the lathe bit we wanted copied.  I painted the different surfaces different colors to be able to talk about what we wanted in the way of angles.  As one mentioned, one change can cause chatter and more frustration.  This all sounds like people want a lot of help but teaching is not easy, just because you hand out aids.
DBQ49er


----------



## mikey

dbq49 said:


> I did not read any where in this thread what kind of tool holder will be used.  A quick change holder or a lantern holder.  I have read some want to use a belt sander, bench grinder but no mention of a tool grinder.   Then what about the grinding stones on these grinders.  And I did not read anything about using a wet stone to polish the edge, a diamond stick to polish, what about a water stone?  When I was teaching machining, we used a 2x2 wood stick shaped to the lathe bit we wanted copied.  I painted the different surfaces different colors to be able to talk about what we wanted in the way of angles.  As one mentioned, one change can cause chatter and more frustration.  This all sounds like people want a lot of help but teaching is not easy, just because you hand out aids.
> DBQ49er



D, I agree that teaching tool grinding and geometry is not easy but try teaching it by typing the words over the internet. I agree that wooden models used while standing in front of a class is the way to go but I didn't have that luxury. I've tried to help guys grind tools before but only had varying amounts of success. The models we used in this discussion seemed to be the most effective way to get the points across and we have seen multiple examples of fine tools ground by quite a few of our guys here so, given the limitations of the teaching medium and the subject matter, I consider this effort a success.

Grinding tools can be done by wheel or belt and the choice is up to the user. My bias is towards using a belt and I made it clear that this is *my* practice. We have had a pretty extensive side discussion about that and some of the guys have built some pretty impressive belt sanders to grind tools with, which is cool. Unfortunately, not many of us hobby types have a tool and cutter grinder in our arsenal, including me, so we'll just have to use what we have.

I also made it clear that I prefer diamond stones to hone with and discussed how they are used for that purpose. I also mentioned oil stones briefly for producing a really fine finish on a tool. 

As for tool holders, almost nobody uses lantern tool posts anymore and the tool angles used in this discussion are intended for the more modern quick change tool posts. That is a given in this discussion.

My goal here was to help guys grind a decent lathe tool, not provide an exhaustive course on lathe tools; I've already done that elsewhere and provided references to it. The biggest barrier for most guys, especially new guys, is to wrap their heads around how to physically grind the various angles properly. Teaching how to do that over the net, without being there in person to guide them, is a bigger challenge than it might seem. 

I did the best I could with it.


----------



## ttabbal

I found it very helpful Mike. The detailed text along with the models in hand were very helpful. I now have copies of the models in keystock and will be making real HSS tools soon. I wasn't even thinking of HSS grinding as most of what I found wasn't very clear to me until I was holding an example to bring it together. 

Tool grinders are great, but crazy expensive new and not common used. At least, that's how it is around here. Materials to build a belt grinder are easy though, just some common steel plate and tube and various fasteners.


----------



## thomas s

I too found Mikey's tool grinding very helpful. And his tools work better than anything I have used.


----------



## Z2V

I have watched many YouTube videos on tool grinding. Some using a large chunk of wood and others using actual tool blanks. I managed to grind tools that would cut but not very pretty. 
I have not actually seen Mikey’s tool models but after reading and following his instructions I now have tools that I can make predictable, clean cuts and have a better understanding of how the different angles effect the operation.
If Mike is not a professional educator he would be a great one. I found his instructions very easy to follow and understand.
Hey Mike, how about some YouTube videos, they would be a hit!
Thanks Mike

Jeff


----------



## rac1812

Well I told my wife that it was all Mikey's fault........ belt grinder all finished...... and works like a charm.

Did a piece of 3/8 full length key stock inless  than a minute with 80 grit belt....... hardly heated up the steel.

Wheels from Jeff, D plate from Oregonblade on EBay belts from Red Label build tips from Ttabal...... scary to list the encouragements and tips at the risk of forgetting someone.

Once the work table is at 15 degrees it's a breeze.

Need to wear my new face shield and fabricate a metal shield for the top wheel on the D plate......standing aside is not the way to work.

Will graduate to HSS on the weekend then try them out on my small lathe.  Very happy with the results. I realize that it is overbuilt like a tank but that was/is the stock I usually work with.  Will tear it down when the weather permits....... roughen up the surfaces with the sand blaster and paint with grey POR 15 for a life time of enjoyment.

Ammo box underneath stores my belts with surplus military disseccant bags in the bottom.  12 guage cable stores on the back side and plugs in the welding outlet.


Thanks everyone

Bob C


----------



## Z2V

Looking good Bob, I like how you set your work table angle that’s a good idea, Solid.
Will be really nice all painted up.
Did you get ceramic belts?


----------



## mikey

rac1812 said:


> Well I told my wife that it was all Mikey's fault........ belt grinder all finished...... and works like a charm.



She looks great, Bob! I agree - the tool rest looks really solid. I bet it grinds really nice because of how well you built it. Congrats, and please tell your wife that I had absolutely nothing to do with it - let's blame Jeff, Travis, Dave Harris, DDickey, Twienke and whoever else we can come up with.


----------



## rac1812

No I have not ordered any ceramic belts.....yet!!!!  How much better are they??

Always afraid to use the HD grits...... I used 80 grit today and man does it work nice ...hardly any heat buildup.

I watched a few Utubes on grinders and tool sharpening and ne guy had made some aluminum blocks. 3/4x1x4 inchers, with channels grooved in by a milling machine at about 15 degrees in a cross shape specifically for 1/4, 5/16, and 3/8 and makes for holding the tool bits much easier and safer....  I lack the milling machine but will talk to a local shop about making me a set of 3.

During the summer, when I can fire up an old forge outside the barn, I may try my hand at making a few knives from old  high carbon buzz saw blades just for the heck of it.  I assisted a blacksmith at a pioneer village outside of Toronto years ago and I have made my own die for square nails, hand made hinges for a chest and a few camp site cooking irons.  I know just enough to be dangerous.

Now that I have the grinder all kind of new horizons are in sight.  In reproducing my cargo box during the Summer, I will be fabricating strap hinges from 1/4 by 2 inch strapping, the hinge pins, and devices to keep the opening side panels and tailgate and leanring how to hot rivet things in place.  The grinder will be earning its keep with the finishing touch.

Thanks again for all the support.

Bob C


----------



## ttabbal

Well dang. I have tool rest envy now.  

And no, we blame Mike for grinders and HSS tooling in general. I'm not sure what we blame me for yet. Making off size parts?


----------



## tweinke

I don't think any one can blame me for anything.......   I will admit to possibly putting a few ideas out there...... Besides that there are no pictures to prove any thing.....    Thanks to Mikey and ALL the others here I can grind a tool that will work pretty good on my flexible machine now if I could just finish my belt grinder I may post a picture or two.


----------



## mikey

rac1812 said:


> No I have not ordered any ceramic belts.....yet!!!!  How much better are they??
> 
> Always afraid to use the HD grits...... I used 80 grit today and man does it work nice ...hardly any heat buildup.



Bob, try the ceramic belts - they cut much faster and cooler than the Alum. Oxide belts. I won't ever go back to AO.

Before you think about having those blocks machined, try grinding your tools by hand. The ceramic belts grind so cool that I don't think you need those blocks. Just dip the tool in water after grinding each face and I don't think you'll feel much heat.


----------



## shorton

I'm late to this party.  A lot to read.  Did the model thing take off?  I've used inserts becasue I've been chicken to figure out how to grind.  I've got a couple of lower end belt sanders (no tthe nice 72" versions), a 1" and a 2" discontinued 3-wheel craftsman.  It's one of the ones that runs a little fast and no good way to control it.  I read somewhere a long time ago of a guy who loved that machine for doing his bits.  Anyway, I've got a pretty nice SB9 underbelt lathe and would like to learn how to do some tool grinding.


----------



## tweinke

You're not too late! Read through Mikey's posts toward the beginning, ask a few questions and you will be grinding bits. I have a feeling one of your belt sanders will work with a proper belt. I have a sneaky suspicion you may have read Mikey's article on another site. Happy reading and please do ask questions when they arise!


----------



## shorton

Might have been.  The author had scribed marks on the table as I recall.  At the time I didn't have that belt grinder/sander, they are hard to find now.  But stumbled across one and bought it.


----------



## mikey

Welcome, Shorton. Not late at all. Much has already been written and there should be enough here to help you grind some tools. If you want to see the models, send a PM to @Z2V to arrange it. Ask any questions you have then give it a shot. If you show us a pic of your tools we'll help you refine them if they need it.


----------



## Z2V

Shorton, if you PM me your contact info I’ll get a set of Mikey’s tool models headed your way. It might take a week or so to get them. 
I don’t know how much of the thread you have read so far but the meat and potatoes start on page four. Mikey’s method of grinding tool bits are really easy to follow and result in good cutting tools and a better understanding of how the different angles effect your tool. 
Give it a try!!


----------



## Z2V

mikey said:


> Congrats, and please tell your wife that I had absolutely nothing to do with it - let's blame Jeff, Travis, Dave Harris, DDickey, Twienke and whoever else we can come up with.



Ok guys, I’ll take the blame. I’m sure I was not the first of the bunch to make a belt grinder but I’ve been blamed for so many things for so many years I’ve developed pretty solid shoulders, and a don’t give a crap attitude. LOL  

I have a old 8” Craftsman bench grinder I haven’t used since I made the belt grinder.

Ceramic belts are the way to go also

It’s all fun


----------



## ttabbal

My grinder and I had a little chat today. Threading tools, square tools both with L/R versions. And a knife tool. 36 grit ceramic belt, a quick touch with 150 grit, then honed with diamond cards. They feel very sharp. Planning on trying them out later tonight. Thanks @mikey!


----------



## mikey

Looks good! You went to town on that grinder today.

Let us know how they work for you.


----------



## ttabbal

I got a chance to try some of them out. I did a quick hand facing and turning with the knife and square tools. I needed to radius the square tool a little more, but I got good finish passes and could take deep roughing cuts in 12L14 and 6061. I was also able to do a quick single point thread (3/8-24) which worked great with a couple nuts I had on hand. 

I switched to the lower speed range and mostly ran at 250-300 RPM. The only slight issue I had was long stringy chips in aluminum, but I get that with carbide as well and managed to get it under control with speed changes. 

Power feed finish passes looked better than the insert tools. The inserts are very sharp though, so I could probably radius those and improve things somewhat. 

Overall I think I'll be using these a lot. This batch was ground from the Chinese 50 pack we discussed from ebay a while back. 

I need more tool holders. Pffffttt...


----------



## mikey

It takes a while to get used to these tools. Go back and look at the discussion we had with HBilly about testing the tools on his lathe, both roughing and finishing, and see what happens. I also suggest you try grinding a general purpose tool with standard angles you find in the table and compare it to your square tool to see what the differences are. Do the same with your carbide insert tooling so you know what all these tool types can do. Then you can choose the right tool for the job. Good work, Travis!


----------



## ttabbal

mikey said:


> Shape: general purpose
> Relief angles: 15 degrees for side and end
> Side Rake: 18 degrees
> Back Rake: 40 degrees
> Nose Radius: 1/32"



I want to see if I have understood what I've been reading here.. And re-reading..  

To make this, I would start with the basic layout of the square tool, the first two, grinds on the end of the tool would be 15 degrees like the examples. The rake angles would be made by setting the table to 18 degrees, the line on the table to 40 degrees, then grind hanging off the side of the table/belt. Then radius the tip. 

Am I close?


----------



## mikey

ttabbal said:


> Am I close?



No, you're dead on. This is a severe amount of back rake and your hand is close to the belt so be sure to use a push block and concentrate. I do the rake grind in two stages - rough to get close and a bit slower to make sure I stop just as the grind reaches the tip. 

You got this, T. You will really like this aluminum cutter.


----------



## ttabbal

mikey said:


> No, you're dead on. This is a severe amount of back rake and your hand is close to the belt so be sure to use a push block and concentrate. I do the rake grind in two stages - rough to get close and a bit slower to make sure I stop just as the grind reaches the tip.
> 
> You got this, T. You will really like this aluminum cutter.




Lots of rake indeed. Interesting. I might have to give thought to making the table go around the belt a little more for added control. I usually use another blank as a push stick, perhaps not the best choice. A 36 grit belt at 500+ SFPM is not something I want my fingers getting into. That thing removes HSS fast, I don't want to know how fast it removes fingers.


----------



## Brento

ttabbal said:


> Lots of rake indeed. Interesting. I might have to give thought to making the table go around the belt a little more for added control. I usually use another blank as a push stick, perhaps not the best choice. A 36 grit belt at 500+ SFPM is not something I want my fingers getting into. That thing removes HSS fast, I don't want to know how fast it removes fingers.


Its just a tickle


----------



## mikey

ttabbal said:


> Lots of rake indeed. Interesting. I might have to give thought to making the table go around the belt a little more for added control. I usually use another blank as a push stick, perhaps not the best choice. A 36 grit belt at 500+ SFPM is not something I want my fingers getting into. That thing removes HSS fast, I don't want to know how fast it removes fingers.



I use an auxiliary table that sits on top of my steel table for grinding rake angles. It has a really good support ear on the right side of the belt and that makes all the difference. I highly recommend you use wood for a push block, T; much safer for you. 

Trust me; a belt will go down to the bone in a fraction of a second so do not slip and do not lose your focus.


----------



## rac1812

Some issue that I have observed from Utube.

All tool holders are not created equal!!!!!!!!

I still use a lamp tool post with a rocker and shims and also some old fashion Atlas/Williams tool holders........ have not invested yet in a small OXA quick change tool post.

It seems that your tools have to be ground to match the tool post you intend to use.

The modern quick change tool post hold the tool/cutter  parallel to the bed and Mikey's basic model of 15 degrees all around the 3 sides would work best .

But if I use the basic model in my old fashion Atlas tool holder _it is already angled about 16.5 degrees_ therefore my  back rake is now 31 degrees +-
which means I could leave the top flat or just touch it up for sharpeness.

Now if I use the lamp post with a rocker, using a 3/8 cutter, I can leave it flat on the rocker and grind a back rake as a typical Mikey tool for the proper angle.........  or curve the rocker and with shims get back to 15 degrees rake with an almost fat top.

Did some grinding today on 5/16 HSS with 80 grit.....worked very well doing the RH side cutter as the belt goes right to the edge of the steel plate backing and I do have over an inch of over hang past the belt to work from...... doing the back rake at 15 degree was fine.......HOWEVER.... when I reverse the process to do a LH cutter my belt will not go close enough to the edge of the backing plate to do a rake grind on the top..... at least not unless I tilt the big D plate and totally re adjust the work table.  I do have a pyroglass plate that is exactly 2 inches wide....once installed my problem be solved.

Worked with safety glasses today ( and gloves) and now appreciate the importance of good lighting to see what you are doing....so a goose neck light is a necessity......  usually cheap at flea markets.

With the 80 grit zirconium on HSS the heat is very controllable...... first the work table serves as a good heat sink....and when necessary a quick dip in a plastic butter dish filled with snow works wonders.

Belt speed is at its lowest....direct ratio with the 3450 motor with 4 inch drive pulley..... I don't see the need to go any faster.

Sheepishly I have not yet tried my new cutters on the lathe yet!!!!!!

Bob C


----------



## mikey

Bob, you're right; when using a lantern tool post the back rake angles are built in to many of the holders so you need to modify your tool grind accordingly. You might consider going to a QCTP - way more solid and versatile for altering your lead angles. 

Let us know how your tools work out!


----------



## ttabbal

Try the cutters. I'm really digging mine. There's room for improvement, but I think it's mostly me learning how to use them well and practicing my grinding technique. 

I made the aluminum tool. I think @mikey is my patron saint of aluminum cutting now. Grinding it was a little tricky, but I got a decent grind. Using finer belts polishes them up fast. I didn't need to hone as much. I went to 400 this time. 

Rough cuts are amazing with this thing. I stopped at 50 thou but the lathe didn't even seem to notice it was cutting. Finish cuts took a few tries with the nose radius and tool angle, but I got some nice finish passes down to 1 thou. Turning to a shoulder and facing out is easy as well.


----------



## Z2V

That aluminum tool cuts great, I agree. I have ground left and right hand for turning and facing. I’m with you also on needing more tool holders. I’ve made tools for stainless, brass, aluminum, and steel, not to mention 60* threading tools. I talked to Matt at PM today but forgot to order more holders. 
Good depth of the work table on the grinder wheel or belt definitely makes a difference in hitting the rake angles easily. 
The best part for me out of this thread is understanding how to relate the tool angles to the grinder cutting them. A combination of work table angle related to grinding surface and the angle of tool on that table related to the grinding surface. 
Mike has done a great job explaining these angles in the grinding process.
It’s a work in progress and a fun time doing it.


----------



## mikey

ttabbal said:


> I made the aluminum tool. I think @mikey is my patron saint of aluminum cutting now. Grinding it was a little tricky, but I got a decent grind. Using finer belts polishes them up fast. I didn't need to hone as much. I went to 400 this time.
> 
> Rough cuts are amazing with this thing. I stopped at 50 thou but the lathe didn't even seem to notice it was cutting. Finish cuts took a few tries with the nose radius and tool angle, but I got some nice finish passes down to 1 thou. Turning to a shoulder and facing out is easy as well.



Been called a lot of things but never a saint!

Glad that tool worked out for you guys. When a tool cuts what you dial in, whether its a heavy cut or a tiny one, it is a pleasure to use. This is what I meant about optimizing the geometry to accommodate a material class; the tool just works better than a standard geometry tool. For those of you who haven't tried grinding this aluminum turning tool, you might want to have a go at it. Hobby guys turn a lot of aluminum and this tool makes it easy and it finishes well, too. 

The one area where you will really see the value of this tool is when trying to come in on a critical dimension. When using an inserted carbide tool, you cannot take too fine a cut because the insert will deflect or may not cut at all. Not so with a sharp HSS tool like this one. If you can dial in the cut, the tool will usually cut it. For example, say you need to take off 0.0014" off the diameter. With a carbide tool, this is going to be really tough to do but with a sharp HSS tool, you can usually interpolate that 0.0007" and come in on size. 

This is why I suggested to HB and Ttalbbal to try taking both heavy and tiny cuts - to see what the tool can do. How deep can the tool rough and at what speed and feed? How far away from your target size do you need to slow down and take sizing cuts to get close enough to dial in that final pass? These are things you must know if you want to do accurate work and the only way to know it is to cut it.

I should tell you that when using inserts, get to know them well, too. You will find that when an insert is broken in and stable, it will cut consistently. If you take a roughing cut twice in a row, the reduction in diameter will be proportionally the same. If you know that the insert finishes well with a certain depth of cut then you can rough until you are at that finishing depth of cut away, then dial it in. Knowing how your tool likes to cut is really important, with carbide or with HSS. It is up to you to figure this out and the only way to do that is to cut with it and learn what it wants from you.


----------



## ttabbal

To be fair, it's not a very good position. No pay, benefits etc.. You just answer endless questions from goofy noobs like me about aluminum tools.  

I still have a lot to learn about tool geometry etc, but it makes a lot more sense now. Still working my way to better finishes and tolerances. I expect that's a never ending pursuit. But I have a grinder and a pile of bits to try it out with. 

Thinking of new things, I'm going to be working with graphite in the near future. I know it's dusty and messy and will have a shop vac set up with a water trap for most of the dust. And breathing protection, don't want to inhale that crap. And of course through cleaning afterward. But what about tools? I suspect the angles don't need to be very sharp as it's going to mostly turn to dust as I cut it. It will need to be sharp to get a decent finish I would think. Any other considerations I should have when making a tool for something like this?


----------



## mikey

Hmm, interesting question. I have not worked with graphite before so I do not know the properties of it. I do know it is very abrasive so perhaps this is an instance where a carbide tool might be best? 

What are you making - a nozzle for one of your rockets?


----------



## ttabbal

Yes, nozzles for the motors. I had not considered it being abrasive, isn't it used as dry lubricant? I have some people over on that side I can ask about it, I just wondered if there might be something useful to contribute here. I know some of them grind down spade bits to make form tools for the cones.


----------



## mikey

Not having machined it I'm next to useless but just on a guess, I would personally try a tool that cuts really easily to reduce internal stress on the graphite matrix. My main concern would be to reduce rubbing that would induce heat so I would increase the relief angles. I don't think it is a particularly tough material so I would go conservative on the rake angles. I have no idea how it finishes so maybe a 1/32" nose radius?

Okay, so, I would try 15-18 degrees of side and end relief, 12-15 degrees of side rake, 10-12 degrees back rake and 1/32" nose radius. I would try it and adjust the tool angles to optimize the cut. The only way to tell is to grind a tool and give it a go.

I watched a video on turning graphite and it sends up a cloud of particles. If I was to turn that stuff, I would cover everything in the shop, cover up everything on the lathe that I could, stuff a rag or paper towel moistened with oil inside my spindle bore and put up a BIG vacuum port - maybe two vacuum ports - and then clean the lathe and the room afterwards. I would also use a respirator on myself. 

Just curious by why would you use graphite instead of mild steel? Could you not use 12L14?


----------



## ch2co

in the long long ago i machined / drilled some graphite blocks.  Didn't seem to be any problem. Just another form of carbon, 
however so is diamond.


----------



## ttabbal

Thanks for the tips Mike! I know I'm a bit off in the woods on this one. Vacuum, respirator, and others will be employed. I'm still deciding on how I want to go about it before I try cutting any. My hope, and reports from others indicate, that dust can mostly be controlled with shopvacs. I imagine speeds and feeds have to be low for that to work. 

The materials are limited by the insurance carriers the national groups use. Motors and the rockets themselves have to be made from frangible material. Some steel and such can be used, but it has to be a small part of the overall mass and motor components cannot be steel. So it tends to be limited to things like fasteners to anchor recovery systems. About the only metal allowed is aluminum. If I were able to fly without the groups and deal with all the legal stuff myself, I could use steel. There are some people doing that, just not in Utah. Nozzles in aluminum don't work well due to the heat. Aluminum cases have thermal insulation liners that protect the aluminum from the worst of it. Phenolic is another choice, but it seems hard to get in large sizes. It also erodes during the burn, changing the motor performance in flight. That also means the nozzles can only be used a small number of times before they erode too much. Graphite tends to hold up for dozens of flights.


----------



## mikey

Sounds like graphite is the way to go then. It will be interesting to see what the cutter ends up looking like if you go with HSS.


----------



## ttabbal

Most of what I'm reading online suggests carbide for tool life reasons. I only have one response from the rocket guys so far, and they also suggested carbide with a rounded end for the o-ring grooves. I suspect that's about the inside corner of groove. I have to look at the carbide parting tool and see what it looks like. I could grind an HSS blade that way easily though. 

I might try some HSS just to see what the tools do on it. I have to rough cut it down to diameter anyway, might as well learn something.


----------



## mikey

Keep us posted on this one. I'm interested to see what works for you.


----------



## Sailplane Driver

I'm interested to hear what works on graphite as well.  I need to turn a couple of graphite pistons for a Jan Ridder design flame eater.  I did find this info:

http://www.substech.com/dokuwiki/doku.php?id=machining_graphite_and_carbon


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## Brento

Mikey i love the instructions. Great work. Im going to make aluminum and brass cutters from this. Im thinking of making both tools for each material.


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## mikey

I've been sort of bouncing this around inside my head for awhile and I'm wondering how a square tool would cut this material. The square tool has 15 degree angles all around. That gives us enough relief on the side and end for almost any material, and it has decent amounts of side and back rake to reduce cutting forces so I hope this enough to prevent chipping at the cutting interface. The only way to know is to cut it.

@ttabbal, why not try the square tool on some spare graphite and see how it works? It would allow you to see how the tool performs and hopefully spot any deficiencies. Then we can modify the grind to resolve them.


----------



## mikey

Brento said:


> Mikey i love the instructions. Great work. Im going to make aluminum and brass cutters from this. Im thinking of making both tools for each material.



Thank you, Brento. When you grind the brass tools, leave the top of the tool flat and just hone it; the tool will work great for brass. Let us know how it goes.


----------



## Brento

So dont create any rake for the brass tools?


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## ttabbal

I'll post pictures when I get some graphite turned. I'm building a dust capture setup before I try turning it. 

Watching Clickspring videos, no rake for brass. I haven't tried it, but he gets great finish that way.


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## Brento

Ill draft up my tool bits so i get an idea of what they look like. Not sure when i will get around to grinding them exactly. Still need to finish my other threading tool.


----------



## mikey

Brento said:


> So dont create any rake for the brass tools?



Nope, just grind the side and end, then hone it and put a nose radius on it.


----------



## shorton

My models arrived today, thanks very much.  Waiting on some new ceramic belts to come in.  And I need to order some HSS stock to make my copies.  Any reason to not get Cobalt?  Recommendation for best place to get my blanks?

Also, my lathe is a Southbend9, but has the QC toolpost and holders.  The tool holder's slots are horizontal (same plane as the bed).  It that compatible with these models angles?


----------



## Z2V

I would get the least expensive HSS bits to start with. In fact, Mikey recommends getting cheap key stock for starters just to get the feel for grinding. There will be a learning process. Get comfortable cutting the key stock then move to HSS, save the cobalt for down the road, just my opinion. I’m sure Mikey will be along shortly.
Enjoy


----------



## Brento

Ik this isnt the correct spot to ask this but ik everyone has been talking about building belt grinders fir this very topic. Did everyone build theirs from the fly or did they have drawings to go by?


----------



## Z2V

Brento
Both actually.  Bob, rac1812, built his from scratch as I believe ttabble did. Not sure of the others. I found some drawings for a KMG clone that I used. A lot of drilling and tapping involved but I don’t have a wire feed welder so I went that route. I used a 3 hp treadmill motor on mine.


----------



## shorton

> I would get the least expensive HSS bits to start with.


Thanks Jeff, I ordered some M2 at MSC for $3.67e.


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## Brento

Z2V said:


> Brento
> Both actually.  Bob, rac1812, built his from scratch as I believe ttabble did. Not sure of the others. I found some drawings for a KMG clone that I used. A lot of drilling and tapping involved but I don’t have a wire feed welder so I went that route. I used a 3 hp treadmill motor on mine.


If you ever get the chance to id love to see those for a future project.


----------



## mikey

Z2V said:


> I would get the least expensive HSS bits to start with. In fact, Mikey recommends getting cheap key stock for starters just to get the feel for grinding. There will be a learning process. Get comfortable cutting the key stock then move to HSS, save the cobalt for down the road, just my opinion. I’m sure Mikey will be along shortly.
> Enjoy



Yup, agree with Jeff. Grind on some keystock until you get used to shaping tools, then switch to HSS and get good at that before switching to cobalt.

Cheapest place to buy HSS blanks is ebay.

And yes, the models and the tools you grind when reproducing them will work fine in your QCTP on your 9" lathe. In fact, I think they are the best kind of tools to use for that lathe.


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## rac1812

Build your own it's a lot of fun and personal satisfaction...... but there are some caveat.

I did mine like a Sherman tank BUT I used the stock steel I had and was familiar with.  Basically if you can weld half decently you can build your own.  There are numerous models to choose from on Utube and ebay..... my biggest influence was Jefff and Ttabal based on the model of Dan Cormeau??? spelling???

I used 1/4 inch thick trailer reveiver tubing.... 2 inches that fits nicely inside the 2 1/2 trailer receiver..... that receiver tube has no INSIDE welding ridge to grind off.   I am sure that 1/8 or even 1/16 wall thickness would be adaquate.  Respect your skill/tools limitation....... in my case drilling and tapping the perfect hole on the D plate would have been a waste to time and good material so I purchased one ready made from Ebay "Oregonblade" including the platen base....... got a pyroceramic glass plate as well.  Used a spare 2 hp 220 v ac with step pulleys for changing belt speed...... still using the one to one ratio so far.  will eventually paint it whent he weather gets milder around here.......-18C tonite....

Followed gluing instructions to the letter using J B Weld...... sandblasted the glass back side and etched a criss-cross pattern on the steel with the Dremel and a diamond bit.

 I have now graduated to ceramic belts....... caution the 40 grit works fast but tends to throw grit in your face.... so a small guard/defector is in the design stage for the top D plate pulley,,,, I have used a partly worn 220 Alum. Oxide belt for the polishing....works like magic.... and yes I am using a face shield.

I saw a Utube where they were using a machined aluminum block to hold the cutter piece when grinding.....being limited by the lack of a milling machine I made some out of hard maple..... which works nice as proof of concept........ machine shops gets expensive so I am thinking of building a similar jig using Key stock welded to a 1/8 plate........ will have pictures soon as I can work out the angle details...... now going of a 30 degrees slot for the side and a 15 degrees for the rake.   Will see how that works out.....eventually will make 3 sets 1/4, 5/16, /3/8.

Look at the previous postings of my completed machine...... will gladly answer any questions to the best of my abilities.  Be prepared to turn on the creative juices....... lots of examples out there...... be prepared to adjust the belt tracking by adding or removing washers on the axles to get the best natural tracking......... fine tune with the tracking adjustments.   

Finally got some belt lub....... seems to work nice but having changed to ceramic belt at the same time as the belt lub it is hard to tell which influence what!!!

one closing question..... it seems inevitable that the rake angle is always easier to gring on the RH side of the platen, which wears out that edge first.....  any suggestions on how to get around that???  I can use the LH side for the LH tools but it is not as easy......considering reverting to a wheel grinder to rough out the rake angle and finish/polish with the belt>>>>!!!!!

I have been dealing with Red Label on Ebay for the belts...... fresh stock, very quick turn around, good selection and competitive prices.

Above all keep it simple and have fun!!!

Bob C


----------



## Z2V

one closing question..... it seems inevitable that the rake angle is always easier to gring on the RH side of the platen, which wears out that edge first.....  any suggestions on how to get around that???  I can use the LH side for the LH tools but it is not as easy......considering reverting to a wheel grinder to rough out the rake angle and finish/polish with the belt>>>>!!!!!
Bob C[/QUOTE]

Why not flip the belt around to even out the wear. The ceramics I have are not directional, are yours?


----------



## rac1812

Arrows ????         .......... didn't even see the Indians.....

My Ceramic is far from being worn...... the first edge to go was the AO 220 which I now use for polishing....  been using the old AO to put on a fine round radius on the bits....... but it is hard to control an even radius

All my belts have arrows that I recall....... will need to check specifically the ceramic belts.......  having broken so many 42 in. belts, I am trying to go by the rules and follow the arrows on the big grinder.

How "BIG" a nono is it to reverse the belts????   you would get a fresh bite from the grits......

Ceramic runs real cool and fast.... I have 36 to 120 but have only tried the 36 so far.   All my practice grinds on key stock and HSS have been done with AO so if the belt is tired and worn so be it.  

It seems that cutting bits in HSS or even cobalt are cheaper by the lot size based on Ebay....... almost $1.00 each HSS by the lot of 60.

Key stock I get from the local fabricator, who uses it in fancy metal work...... is about $7. for a 10 foot length of 1/4x1/4 in.

Cheers


----------



## mikey

shorton said:


> ... I need to order some HSS stock ...



Hey Shorton, this deal is still available on eBay: https://www.ebay.com/itm/50pcs-3-8-...e=STRK:MEBIDX:IT&_trksid=p2060353.m2749.l2649


----------



## rac1812

I have already done that....not sure of quality but a good price.....


----------



## ttabbal

rac1812 said:


> I have already done that....not sure of quality but a good price.....



I've been cutting with a few of them and have been happy with them. Particularly for the price.


----------



## Aaron_W

I ran across this youtube video the other night. I found it a good visual demonstration of what the various cuts are for and how they work, He starts off by trying to turn a piece of aluminum with a flat square piece of HSS, and then progressively adds relief and rake angles to show how they improve the cut. Also a little bit of discussion about the function of chip breakers near the end.

The purpose of these features has been well documented here, but I always find visual aids help.


----------



## mikey

I really liked how his computer graphics helped to illustrate the angles he was talking about, and also how he was able to show how each added angle changed the cut. There are very few videos that address how a turning tool cuts and in my opinion, the more, the better. 

In this thread, we discussed *how to* grind a tool and barely touched on how a tool actually works. We can discuss how it works if that is of interest to you guys. I've tried that discussion before and judging from the few responses I got, my impression is that most guys could care less how the tool works as long as it works.


----------



## Aaron_W

It is a lot to absorb when we are just trying not to grind our finger tips.

I run across a lot of comments about HSS being useful not just as an economical tool, but also for the ability to grind the custom tool you need which may not exist unless you make it yourself.

It is rather hard to make your own tool without understanding what it is that each cut does. At least for myself it isn't that I couldn't care less how it works so much as I'm still trying to figure out what is my fault and which is because of the tool. So many variables between feed rate, depth of cut, angle of the tool, material etc. 

As far as a lack of discussion I suspect it is more being overwhelmed and not having anything to add than a lack of interest.

It might help to talk about evaluating a cut to figure out what is going on. To be honest I'm just guessing when a part isn't turning out how I hoped. I'll adjust RPM, try adding some lubricant and adjust the depth of cut, sometimes that works sometimes I finish the piece with a fine and sand paper.


----------



## tweinke

I agree with Aaron. It would be nice to get the how and why version of the story though. The bits I have ground using the models work well, the thought of playing with the angles has occurred to me but which to change and why escapes me. Definitely lack of knowledge and feeling overwhelmed but the relationship of the angles. Might be interesting even to have the Cliff notes version and then expand from there.


----------



## Aaron_W

tweinke said:


> I agree with Aaron. It would be nice to get the how and why version of the story though. The bits I have ground using the models work well, the thought of playing with the angles has occurred to me but which to change and why escapes me. Definitely lack of knowledge and feeling overwhelmed but the relationship of the angles. Might be interesting even to have the Cliff notes version and then expand from there.



and then there is the tool that seems to work fine, maybe it could work better but why tempt fate.


----------



## mikey

Aaron_W said:


> It is a lot to absorb when we are just trying not to grind our finger tips.



I totally get that. Just learning how to move your hands to grind a useful tool is hard enough, let alone trying to absorb how the tool actually works.



Aaron_W said:


> It is rather hard to make your own tool without understanding what it is that each cut does. At least for myself it isn't that I couldn't care less how it works so much as I'm still trying to figure out what is my fault and which is because of the tool. *So many variables between feed rate, depth of cut, angle of the tool, material etc. ... *It might help to talk about evaluating a cut to figure out what is going on. To be honest I'm just guessing when a part isn't turning out how I hoped. I'll adjust RPM, try adding some lubricant and adjust the depth of cut, sometimes that works sometimes I finish the piece with a fine and sand paper.



Yup, it's called "learning to use the lathe." Having good tools makes it easier but there is still a lot to learn. That's the fun part, though. It takes time and experience, Aaron, but it will come.


----------



## mikey

tweinke said:


> I agree with Aaron. It would be nice to get the how and why version of the story though. The bits I have ground using the models work well, the thought of playing with the angles has occurred to me but *which to change and why escapes me. Definitely lack of knowledge and feeling overwhelmed but the relationship of the angles.* Might be interesting even to have the Cliff notes version and then expand from there.



Hey Todd,
Yeah, I admit that figuring out how the angles relate to each other and how to change them to suit the material is not intuitive or simple to understand. However, before you try to figure out how to do that, you have to understand what each angle on the tool does. Then you have to anticipate what an angle change will do to improve performance in a given material class. 

The hard part is that none of this is written down in the literature/books. In fact, I bet we have covered more  HSS tool information in this thread than is covered in any instructional book on the net. How far we take it depends on you guys. If you want the whole shebang then we can do that.


----------



## ttabbal

I wouldn't mind seeing more. It would be interesting to know more about why one would choose certain angles for different faces. When you might want to use a steeper or shallower angle, etc..


----------



## Z2V

I’m not saying much tonight, I have a sore throat but I’m in too!


----------



## tweinke

mikey said:


> The hard part is that none of this is written down in the literature/books. In fact, I bet we have covered more HSS tool information in this thread than is covered in any instructional book on the net.



That statement sums things up pretty well. Thanks to you and all that have participated in this thread for the knowledge that has been shared! Wish it would warm up a little more so I can finish my belt grinder, and then grind tools...........


----------



## mikey

Okay, let me think about how to present this info. Trust me, it is a huge discussion.


----------



## Tombstone

Hi guys I new to this hobby just got myself a lathe a week ago. I had help from a friend that is an x machines but still do little projects for cash on the side. My old man is and maecenas too but haven't done it for 25 year's. This ider of sending the tools for every one to have a feeling of how there look at is and good Ider. I'm interested if you're still doing it. I just downloaded an printed out the guides on page 2 of this threat. Keep the good work up.


----------



## jwmelvin

Three cheers for the whole shabang, Mikey!


----------



## tweinke

Will have the thinking cap dug out for this!!!!!


----------



## Aaron_W

mikey said:


> Okay, let me think about how to present this info. Trust me, it is a huge discussion.



Just a thought, but working through the development of a tool would be very helpful. You've mentioned being unsatisfied with Sherline's right hand tool. Understand that you've probably lost the actual memories of improving it in the sands of time, but maybe you've got one laying around still?

I guess where I'm mainly unclear is what the specific angles do. I understand the relief angles are mainly to clear the the work surface, the rake angles are to help clear the chips and the radius is a compromise between durability and precision. What I don't understand is what the effect of a small angle say 5 degrees of relief does compared to a larger relief of say 20 degrees assuming both keep the work piece from rubbing against the tool.   

I understand that even for experienced machinists some, maybe much of this is trial and error, but it would be nice to at least have a feeling for "if this then try that".


----------



## mikey

Aaron_W said:


> Just a thought, but working through the development of a tool would be very helpful. You've mentioned being unsatisfied with Sherline's right hand tool. Understand that you've probably lost the actual memories of improving it in the sands of time, but maybe you've got one laying around still?
> 
> I guess where I'm mainly unclear is what the specific angles do. I understand the relief angles are mainly to clear the the work surface, the rake angles are to help clear the chips and the radius is a compromise between durability and precision. What I don't understand is what the effect of a small angle say 5 degrees of relief does compared to a larger relief of say 20 degrees assuming both keep the work piece from rubbing against the tool.
> 
> I understand that even for experienced machinists some, maybe much of this is trial and error, but it would be nice to at least have a feeling for "if this then try that".



I'll keep these things in mind as I try to figure out an approach. I am trying to decide how much to include because there is a LOT to this discussion. I will include the function of each angle, what a change to each does and how to decide how much to change. 

The difficulty here is trying to say something in a clear and simple manner when the subject matter is anything but clear and simple.


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## ttabbal

If anyone can do it, it'll be Professor mikey.  sounds like a good plan to start with.


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## tweinke

ttabbal said:


> If anyone can do it, it'll be Professor mikey.  sounds like a good plan to start with.



What he said! We have time, think it out and when your ready to get started I'm sure we will be here. This should be very interesting!


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## Z2V

I’m excited about this going to the next level. Mikey has generated great interest in tool grinding and has done an excellent job of explaining the process of grinding the different angles that make a cutting tool. I’m looking forward to learning more of the mechanics behind the tools next.


----------



## mikey

Okay, we’re going to discuss how a turning tool works. I decided that I am NOT going to discuss cutting theory (Oblique vs Othogonal cutting models or the Merchant Equation) because it would make this discussion hopelessly complex. What I will attempt to do is give you practical information that you can actually apply in your shop.

*So, what happens during an actual cut? *

Have you actually watched your tool cut? If you haven’t paid attention to it, you should. What you will see is that the initial point of contact is the side cutting edge, followed by the nose radius. As the tool cuts, the chip peels off and exits at a downward angle that is about midway between the side and end cutting edges (assuming you have both side and back rake). The side cutting edge and nose radius produces the chip but* the nose radius and end cutting edge produces the FINISH* *when the tool is turned toward the chuck; the side cutting edge and nose radius produces the finish on a finishing cut when the lead angle is turned more toward the tailstock. *Rarely, if ever, is the end cutting edge on anyone’s radar but it should be because it’s important.

In point of fact, every single angle on the tool is important and each one has a function. You will often see guys state that you only need to get the tool angles close and its good enough. I swallowed that line for a number of years and was frustrated because of poor tool performance. Granted, this was on a Sherline lathe but that was actually a good test bed because if a tool cuts well on that little lathe then it is a good tool. After literally thousands of test cuts I know that a change of even a degree or two of a particular angle can make a difference in how the tool cuts.

Okay, let’s discuss the different tool angles on a turning tool. Here is a graphic for reference:

​
*The Side and End Cutting Edge Angles*

These angles define the shape of the tool as seen from the top of the tool. Of all the angles on a turning tool, these two are the least critical. They determine how much *mass* is in the tip and whether or not you can *access a shoulder* but beyond that you have a lot of leeway in how the tool is shaped. When we ground these angles for our models we drew them out as inked lines but in time you will not need to do that.

If you have a QCTP, my suggestion is to stick with a general purpose shape; this gives you enough mass in the tip to tolerate changes to your relief and rake angles without worrying about the tip snapping off in use and it allows you to cut into a shoulder without rubbing.

*The Relief Angles*

Of course, we have two: the side relief angle and the end relief angle.

Most people believe that the only function of the relief angle is clearance and that once you have it, then you have it. Accordingly, it matters little if you use 5° or 15°, right? However, don’t forget that the relief angles are also one half of the cutting edge and, together with the rake angles, they form the cutting edges of the tool. Moreover, they partly determine the included angle of those cutting edges; the greater the relief angle, the narrower the included angle of the cutting edge.




On the left we have the typical turning tool as seen from the end of the tool. The side relief angle combines with the side rake angle to form an included angle. On the right is an increased side relief angle and combined with the same rake angle, the included angle is narrower. What this narrower angle does is *improve penetration* *as the tool moves through the material* and as a result, it takes less power to make the cut. On a Sherline lathe, just this single change (from 7 degrees to 15 degrees) will allow a 1/3 deeper depth of cut. AND it improves the finish.

The angle tables we all use to grind tools calls for relief angles of 8-10 degrees and we are led to believe that this is all we need for “clearance”. Now we know that maybe there is a bit more to it than just clearance.

So, how does this affect the end relief angle? Recall that I said that the end cutting edge is what produces the finish when the tool is roughly perpendicular to the work. If you look at the tip of your tool you will see that the end cutting edge is angled downward, right? In this position, the end cutting edge does not cut a chip; it *shears*. The bulk of the material is taken off by the side cutting edge and nose radius and the end cutting edge shears a fine finish. When combined with the back rake, the included angle at the end cutting edge is like a razor held to the work at an angle that shears cleanly, and the greater the included angle of this edge is, the sharper your shear becomes. Does that make sense?

Now, take a look at your turning tool angle table. Most tables call out for about 2° less end relief vs the side relief. Presumably, this is to add more mass to back up the tip of the tool for strength. In all the years I’ve used a turning tool I have never seen a tool tip break off because I didn’t follow this recommendation. Therefore, *I recommend you use the same amount of relief for both the side and end.*

As in all things, there is no such thing as a free lunch. Increasing the relief angles weakens the cutting edge so tool life may decrease. It isn’t that you will break the edge off but the tool may dull more easily with a lot of heavy cutting. For most of us in a non-production setting, this is no big deal. If you lightly hone your tools after use they will hold up for many years without issues. However, if you plan to use a tool for heavy cuts in hard materials it is wise not to increase the relief angles too much. Be conservative with your relief angle changes and use the rake angles to alter the included angle at the cutting edge instead.

*The Rake Angles*

Again, there are two rake angles: the side and back rake angles.

Of all the angles on a turning tool, the rake angles are the most important because they have a significant impact on penetration, finish, cutting forces (and where they are focused) and cutting temperatures. Just as importantly, they do this with almost no downside or penalty.

Personally, when I think of the rake angles I actually think of them as *planes* because that is what they really are. On two edges of each plane is a cutting edge formed by the relief angle and the top rake surface of the tool. The area behind the cutting edges provides a pathway for chip egress. The angle of this pathway is a combination of both rake angles.

If you grind a tool with only side rake on top of the tool you will see the chip peel off directly perpendicular to the side cutting edge. This tells you that the cutting forces flow perpendicular to the side cutting edge. Now, if you add back rake you will see two things: the origin of the chip will shift toward the tip and the angle of the chip flow will angle back and exit roughly in a line between the side and end cutting edges.

Now you know that you can shift the origin of the chip, the area where the cutting forces are focused, by altering back rake; the more back rake you use, the closer to the tip the forces are focused. As this occurs, the chip thins and accelerates, the result of which is a reduction of cutting forces, cutting temperatures and an improved finish.

Okay, so how do the rake angles reduce cutting forces? I will try to simplify this as much as possible but have a look at this graphic that I blatantly stole off the net:

​
This graphic shows chip formation during an Orthogonal cut. Our tool does not cut this way; it is an Oblique cutting tool. However, the effect of the rake angles on the shear plane is the same. Note that the depth of cut in both cuts in the illustration are the same. Also note that the line, Ø, is actually a PLANE that is as thick and wide as the chip itself.

What you are seeing here is that *as the rake angle increases,* *the shear plane angle increases and the length of the plane decreases* and this leads to chip thinning, a reduction in the force required to produce the chip and an increase in chip velocity as it exits the cut.

_*EDIT: the above paragraph is true; it is also as clear as mud. The picture above, while accurate, has the wrong perspective; turn it 90 degrees clockwise to see what happens during a cut on the lathe.*_

_*What I am saying is that as the rake angles increase (applies to either side or back rake), the included angle of the cutting edge increases - it gets sharper. This causes the chip to thin out and break easier so that it takes less force to move the cutting edge through the cut; the result is a reduction in cutting forces. What we see at the lathe is that it takes less power to make the cut so that a smaller, less rigid lathe can take a cut that it normally could not take when a conventional tool is used. The chip also exits the cut faster so that cutting temperatures are reduced because the heat goes out of the cut with the chip. The effect of rake on the shear plane is WHAT happens; a reduction of cutting forces and cutting temperatures is the RESULT, and trust me, this is a big deal insofar as the results you see at the lathe. *_

Okay, okay, this is getting more into cutting theory than I intended. Suffice to say, the rake angles are important. What you should realize is that BOTH rake angles do this to the chip and their effects are additive. I subjected you to this in order to make sense of the following benefits of the rake angles:

Improves penetration by reducing the included angle at the cutting edges, independent of the relief angles. This reduces cutting forces without weakening the cutting edges, a very big deal.
Thins the chip and accelerates chip flow, thereby reducing both cutting forces and temperatures. Most of the heat in a cutting operation goes out with the chip so this matters. A good case in point is an aluminum cutting tool; a positive rake aluminum cutting tool will rarely, if ever, develop enough heat to have a built up edge. The chip is moving too fast and cool to allow chip welding – pretty cool, eh? (sorry, couldn’t resist the pun!)
Allows us to accommodate different materials. Different materials require different amounts of side and back rake to cut efficiently. This has to do with how the chip forms and breaks … and I am NOT getting into that.
Back rake allows us to tailor where our cutting forces are focused. By increasing back rake we can shift the forces toward the tip to enhance finishes or improve the facing capability of a tool. By reducing back rake we can shift the forces to the side cutting edge to allow for heavier cuts while relying on side rake to reduce cutting forces and temperatures. Back rake isn’t even on most people’s radar; too bad because it is one of the most important angles on a turning tool.
Machinery’s Handbook says that as side and back rake become more positive, cutting forces and cutting temperatures decrease and tool life increases (up to an optimal point, whatever that is) so do not underestimate the value of the rake angles. They are easily the most important angles on your tool.

*Finally, the nose radius*

I have seen all sorts of recommendation for the nose radius, from the “go big for better finishes” to benign neglect. Here is the reality – the nose radius is, for lack of a better term, a shearing device.

Take a good look at your nose radius and you will see that it is actually a really complicated feature. It angles up due to the back rake and also angles to the side because of the side rake. It also has a huge undercut because of both relief angles.

Recall I said that the nose radius and end cutting edge produces the finish on your part and that they do this in a shearing action. The nose radius actually serves as both a transition to the end cutting edge and a participant in the shearing cut the end of the tool produces. As such, the radius doesn’t need to be huge to do this job; it just has to be there.

What’s more, the nose radius is the key cause of radial deflection. Since the tool is more or less fixed, radial cutting forces will move or deflect the work away from the tip of the tool. The bigger the nose radius, the greater the deflection. If the work piece is big and rigid enough you may not see an effect but on a smaller diameter work piece it can deflect enough to produce a taper or chatter.

So, if you want an accurate turning tool that cuts with minimal deflection but still finishes well, keep the nose radius small and rely on the end cutting edge and back rake to produce the finish you need.

How small is small? For general purpose tools used for most materials, I suggest a 1/64” nose radius. For aluminum, brass and plastic tools, 1/32” is enough.

Earlier in this thread I said that I never felt the need for a Shear Tool because my regular tools finished well enough for me. Now you know why I said that; my nose radius IS a shear tool but unlike a regular shear tool, this one can take any cut I can dial in.

Okay, now you know what the angles do and how the tool cuts. Let me hear your questions or comments and we’ll move on to discuss how you can use their properties to modify your tools to work better for you.


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## Z2V

Mike, you referenced the tool at different angles to the work, angled toward the chuck, perpendicular to the work and finish cuts angled toward the tail stock. This is the same tool on the same work at different phases of the job? Roughing to finish cuts? Do you normally shift the angle of the tool to utilize the different features of the tool throughout the job?

I have plenty blank tool bits, I’ll get out on the lathe and pay closer attention to things mentioned here.
Great write up, thanks


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## mikey

Z2V said:


> Mike, you referenced the tool at different angles to the work, angled toward the chuck, perpendicular to the work and finish cuts angled toward the tail stock. This is the same tool on the same work at different phases of the job? Roughing to finish cuts? Do you normally shift the angle of the tool to utilize the different features of the tool throughout the job?
> 
> I have plenty blank tool bits, I’ll get out on the lathe and pay closer attention to things mentioned here.
> Great write up, thanks



Yeah, when we rough the tool is roughly perpendicular to the work or maybe slightly canted towards the chuck and in that position the end cutting edge is in play. When you turn into a shoulder the nose radius and end cutting edge is definitely in play. When doing sizing or finishing cuts the finish is produced by the nose radius and side cutting edge. The important point is that both the side and end cutting edges and the nose radius are important and I brought it to your attention because nobody ever pays any attention to the end cutting edge. They seem to think that the finish on the work piece magically appears or that the side cutting edge produced the finish all by itself - not true.


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## DHarris

GREAT write-up Mikey!  Ok, I've cut and pasted this into the summary document and will continue to do so until we've finished this latest installment of your undergraduate instruction course!  Then I'll upload the finished word document for anyone who whats it.

thanks Mikey!

edit:  MS word document for this "course" is now up to 28 pages of detailed information!!


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## ttabbal

DHarris said:


> edit:  MS word document for this "course" is now up to 28 pages of detailed information!!



Thanks for doing this! I found it very handy to have an "index" when getting started grinding my tools.


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## mikey

DHarris said:


> GREAT write-up Mikey!  Ok, I've cut and pasted this into the summary document and will continue to do so until we've finished this latest installment of your undergraduate instruction course!  Then I'll upload the finished word document for anyone who whats it.
> 
> thanks Mikey!
> 
> edit:  MS word document for this "course" is now up to 28 pages of detailed information!!



Thank you, Dave. Wow, 28 pages - I talk too much!


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## mikey

It occurred to me last night that knowing how the tool and tool angles work is all well and good but it doesn't help if the new guy doesn't even know how to use the tool itself. Aaron pointed this out and I flippantly said that figuring it out is part of the experience. While that's true, it is also arrogant of me.



Aaron_W said:


> It might help to talk about evaluating a cut to figure out what is going on. To be honest I'm just guessing when a part isn't turning out how I hoped. I'll adjust RPM, try adding some lubricant and adjust the depth of cut, sometimes that works sometimes I finish the piece with a fine and sand paper.



Aaron is only one of many new guys who are just starting out. What sets him apart is that he has the courage to put himself out there to ask what might be perceived as a "stupid" newbie question when, in fact, it is a really good question. We can learn to grind a good tool and even learn about tool geometry but if we cannot use the tool effectively then all of that knowledge does absolutely squat. Thanks for the epiphany, Aaron.

I decided to go off on a short tangent and quickly discuss how I set up and take a cut, then evaluate or adapt to the cut. Once that is out of the way, I'll get back to tool modification. I hope this is okay. I also invite the other more experienced guys to jump in and correct, add to or otherwise contribute to this basic approach to turning.

*Setting up*
Let us assume we are using a 3 jaw chuck that most of us own. The 3 jaw holds most round stuff quite well and as long as we don't remove it from the chuck, whatever we turn in it will be on the exact centerline of the lathe. Before chucking a piece up, wipe the jaws clean of debris and deburr one end of the work piece and stick it in the chuck. Be aware that if the piece sticks out more than 2 times the diameter of the piece then you should use a live center to reduce deflection. A Sherline chuck tightens with Tommy bars so you just snug it down onto the work piece but most chucks have a square key that tightens a pinion that rotates the scroll to tighten down on the work piece. On a quality chuck, one pinion will be marked by the factory. If your chuck is marked (dot, hash mark, whatever) then the accuracy of the chuck is obtained only when tightened by that one pinion. If it is not marked then you should take a ground rod and determine which pinion results in the best accuracy and mark it yourself. Your lathe chuck is not a drill chuck; tighten from one pinion only and do so firmly. You do not need to put a thousand pounds of torque on it.

With the work piece in the chuck, mount your lathe tool in the post and get the tip of the tool on the center height of your lathe. It is very educational to see what happens when the tip is above, below and on center and you should try it. Keep tool stickout to a minimum and lock the tool holder firmly in the post. Many turning issues are the result of a tool that is not on center or is not solidly anchored; pay attention to the basics.

*Material and your job*
Every material has a recommended cutting speed (in SFM = surface feet per minute) and it differs depending on which tool you use - HSS or carbide. Here is a useful chart: https://littlemachineshop.com/reference/cuttingspeeds.php. Find the cutting speed for your material and tooling and calculate your lathe speed: *RPM = SFM X 3.82 / diameter of the work piece*. The calculated RPM is not written in stone; you will adjust to the cut as you go. For example, if you are taking a roughing cut and encounter *chatter*, you can do three things: *reduce the lead angle of your tool (turn the tip slightly toward the chuck), reduce speed or increase feed. *

If you use the LMS speed chart, the cutting speeds assume a feed of 0.004”/rev. You need to adjust this as needed to give you a decent result. If you have chatter, feed faster. If you have surface defects (lines or whatever), try feeding slower. If the finish is good then, well, its good. For short pieces with a HSS tool, I often feed manually instead of engaging power feed and tend to feed slower for a good finish. Carbide tools require more consistent feeds but I won’t go into that here. Feeding manually allows you to feel how the tool is cutting and I do this whenever I cut something new to me. I am feeling for a slight resistance to the feed as the tool cuts; this gives me a good idea of what the feed rate should be for that speed in that material.

Okay, we’re almost ready to cut. Pick a cutting fluid if you’re going to use it. Brass, most plastics and cast iron do not require cutting fluids. You don't need a flood; brush it on.

*Face the part*
Almost all lathe work starts with facing. Turn the tool so that the side cutting edge just behind the nose radius contacts the work and lock it down. Turn the chuck by hand so the tool contacts the highest spot and back the carriage out. Feed in a few thou in the longitudinal direction and turn the cross slide in to face the part. Repeat as needed to obtain a clean face. If you have a nib on the face after facing then your tool is not on center height; if the nib is round, the tool is too low. If the nib is cone shaped, the tool is too high. Now you can center drill it if needed or continue on to turn the OD.

*Turn the part*
Realign the tool so the shank is perpendicular to the work piece. A square tool will rough well in this position because the lead angle (the side cutting edge angle) is built into the design. If the tool chatters, turn it slightly toward the chuck and the chatter will usually resolve. This is because reducing the lead angle is the equivalent of reducing speed and increasing feed, just by turning the tool toward the chuck.

Pick a depth of cut. On a small lathe and especially in materials that you haven’t turned before, a roughing depth of cut should be conservative. Forget the Testosterone thing; big hairy cuts are for YouTube guys. Start small, maybe 0.0250” deep and make a cut. You are trying to see if the cut goes well with the speed, feed, tool, lathe and cutting fluid you have. If the lathe cuts without strain and the finish is acceptable, make another pass at 0.040” deep. If the lathe handles it and the finish is still good, go to 0.050” and so on. You are learning how heavy a roughing cut you can make with your set up for that material. When you are satisfied with the results, take note of how the tool is positioned and what your speeds and feeds and depth of cut was and write it down. Over time, you will know this from experience but for now a record is invaluable.

Now realign the tool so the tip is pointing about 10-15° toward the tail stock. You are going to take a sizing cut. Sizing cuts are cuts that you do after a roughing cut but before a finish cut. The purpose of a sizing cut is to smooth out the rougher surface produced by the roughing cut; this gives you an accurate surface you can measure so you know how deep a finish cut you need to come in on size. Sizing cuts are not deep cuts; typically, I use 0.010”, just enough to take off any surface irregularities. Once the surface is clean, measure it and see how much more you need to take off to hit your final size. I normally take additional sizing cuts until I am about 0.010” from final size, then I reset the tool an additional 5-10° toward the tail stock; this is my finishing position.

After touching off on the part, I dial in half the remaining depth of cut and make a pass. Then I measure the OD carefully and dial in the required depth to come in on size. A square tool will usually cut what I dial in and I have come to rely on its accuracy. It also produces a very fine finish when the tool is turned as above because it is shearing with the nose radius and the side cutting edge.

Now you can part off and you’re done.

I encourage you to practice, practice, and practice. If I could pick one material to learn from it would be 12L14. It will tell you when you’re doing it right and when you’re doing it wrong. 

*Use your senses* when running a machine. Listen to her and feel the lathe as it tightens up under the strain of the cut; you will know when she is cutting well and when she isn’t. I can tell when my depth of cut is too deep or if my tool needs honing just from the way my lathe feels in a cut, even if I cannot see this on the work surface. In time, you will, too.

Hope this helps. If I missed something, and I’m sure I did, then ask and we’ll sort it out.


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## DHarris

Ok, I've included this latest explanation at the front of the full document!  NOW 30 pages!  I'll give it a final format and add a table of contents to the beginning when you think we are basically done adding chapters to your first, soon to be, published machining book!

good work Mikey!  and thanks!


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## mikey

DHarris said:


> Ok, I've included this latest explanation at the front of the full document!  NOW 30 pages!  I'll give it a final format and add a table of contents to the beginning when you think we are basically done adding chapters to your first, soon to be, published machining book!
> 
> good work Mikey!  and thanks!



Thanks again, Dave. This started out as a simple gesture to the forum members and has morphed into some monster mental regurgitation thing. Sadly, I'm not done yet. I still have the tool mod part to go but after that I will shut up ... I think.


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## Z2V

Nah, nah, don’t shut up! If your talkin we are learning,
Thanks Mikey


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## ttabbal

I'm still digesting the last class's work. I think I'm getting there. That the "clearance" angles actually matter made me smile. I thought they had to, but I kept seeing people say that you just need clearance to not rub. I'm thinking my grinder and I are going to need to have another chat here soon. I have an aluminum tool to fix, and some test tools to grind. I want to see what some of the angles do when I change them.


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## Aaron_W

Thank you. I have questions but I have to re-read these last few posts a couple of times so that my questions make sense.


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## mikey

Aaron_W said:


> Thank you. I have questions but I have to re-read these last few posts a couple of times so that my questions make sense.



When I have posted detailed discussions on tool geometry in the past, the forum suddenly goes quiet. The last time this happened, I actually PM'd one of our gracious mods and the OP of the thread and expressed concern that the posts had shut down! I was told to be patient and things would pick up; they never did. I am convinced that I lost of lot of the guys in the details, which is why I said that this stuff is anything but clear and simple and is also why I didn't do it in the first place.

At this point in my "grinding career", I can see tip geometry in my mind. I see every angle and how they relate to one another. I can mentally see how each will change if I change one or more of the angles and I can anticipate what will happen as a result of those changes with surprising accuracy. For me, what I have written here is like Tool Grinding 101 but it is really, really complicated to the uninitiated. 

What I'm trying to say is that I understand how you guys feel. You do not need to understand any of this stuff; all you need to do is learn to grind a tool so you can make chips. If you can grind a Square Tool, that should be enough to satisfy most guys and you don't have to understand anything else. However, there is one guy, maybe two, who want to go further. I am doing all of this for those guys and I hope they learn this stuff well. One day, I will be gone and somebody needs to pick it up. It is my hope that that somebody is a member of this thread because this information is not available anywhere else on the Net. 

And don't think you can rely on Bonehead. Not only is he going to **** you off, but he can't type!


----------



## tweinke

Mikey, still digesting what you have shared with us. I think I get it at least to a point. I was thinking that I need to play with the angles and see if that helps make things clearer. Sort of like in school when you were given a lesson and then told to make an example to prove it. I'm trying to dream up my next move. For me my next thing is to finish my grinder, cold in the shop or not. At that point when time allows there will not be a piece of HSS safe!!!! Please do continue even if this goes over my head and my eyes glaze over knowing the information is here gives me the piece of mind to know that as I learn and have questions I have an in-depth reference to refer to. The time you and Jeff have spent to help those of us here is priceless and I very much appreciate the hard work and excellent knowledge you have shared.


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## mikey

I put an edit in post 618. Please see it helps.


----------



## mikey

tweinke said:


> Mikey, still digesting what you have shared with us. I think I get it at least to a point. I was thinking that I need to play with the angles and see if that helps make things clearer. Sort of like in school when you were given a lesson and then told to make an example to prove it. I'm trying to dream up my next move. For me my next thing is to finish my grinder, cold in the shop or not. At that point when time allows there will not be a piece of HSS safe!!!! Please do continue even if this goes over my head and my eyes glaze over knowing the information is here gives me the piece of mind to know that as I learn and have questions I have an in-depth reference to refer to. The time you and Jeff have spent to help those of us here is priceless and I very much appreciate the hard work and excellent knowledge you have shared.



Thanks, Todd. I will finish what I started and give you the info to modify your tools as I said I would do, not to worry. Once I do that, you should have the ammo you need to play with your grinding.

I have always felt that if a student fails to assimilate the information, it is not the fault of the student; it is the fault of the teacher for not presenting the information in a manner that can be easily understood. I am trying and I am failing and it sucks. This is why it is taking so long to get the tool mod part of this to you guys. I'm trying to simplify it so anyone can get it. I may fail at that, too, but it won't be from lack of effort.


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## tweinke

I do not believe you are failing by any means. This is a complicated topic. In my case I have no formal training in any of this and it does interest me. It seems to me that as I grasp the topics by using your info the picture gets clearer in my mind. I am sure that face to face it would be simpler to convey your thoughts. Also on my part at least the information being a bit over my head so to speak gives me a push to learn more. I consider all you have given a huge resource that will be referenced now and in the future. Besides that the models will always give a starting point that will work so there is a fall back incase I fall off the learning cliff.


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## Z2V

tweinke,  I couldn’t have said it better.


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## Aaron_W

mikey said:


> When I have posted detailed discussions on tool geometry in the past, the forum suddenly goes quiet. The last time this happened, I actually PM'd one of our gracious mods and the OP of the thread and expressed concern that the posts had shut down! I was told to be patient and things would pick up; they never did. I am convinced that I lost of lot of the guys in the details, which is why I said that this stuff is anything but clear and simple and is also why I didn't do it in the first place.
> 
> At this point in my "grinding career", I can see tip geometry in my mind. I see every angle and how they relate to one another. I can mentally see how each will change if I change one or more of the angles and I can anticipate what will happen as a result of those changes with surprising accuracy. For me, what I have written here is like Tool Grinding 101 but it is really, really complicated to the uninitiated.
> 
> What I'm trying to say is that I understand how you guys feel. You do not need to understand any of this stuff; all you need to do is learn to grind a tool so you can make chips. If you can grind a Square Tool, that should be enough to satisfy most guys and you don't have to understand anything else. However, there is one guy, maybe two, who want to go further. I am doing all of this for those guys and I hope they learn this stuff well. One day, I will be gone and somebody needs to pick it up. It is my hope that that somebody is a member of this thread because this information is not available anywhere else on the Net.
> 
> And don't think you can rely on Bonehead. Not only is he going to **** you off, but he can't type!




Nope, I will be back with questions just have distractions at the moment that are far less fun than turning metal.


What you have written makes sense and many questions are answered within the posts themselves. That requires re-reading looking for different things each time. I really appreciate you taking the time lay it all out like this.

It is like the give a guy a fish or teach a guy to fish. We are busy trying not to jamb the hook in our thumb right now.


----------



## mikey

Thanks, Guys, but time will tell how this goes. I've been writing for two days and keep trying to simplify - its hard.


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## thomas s

Mikey, Thank you for taking the time to do this. For me this has been one of the best threads on this forum.


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## Tombstone

+2


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## mikey

thomas s said:


> Mikey, Thank you for taking the time to do this. For me this has been one of the best threads on this forum.



Thanks, Thomas, I do appreciate it. Coming from a veteran machinist like you, it means a lot.


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## ttabbal

When I was first looking into getting a lathe, I looked into grinding HSS. I read lots of stuff, watched videos, but it never "clicked". Your directions and the models made it come together enough to feel confident making tools and keeping them going. I did my first repairs on some tools and they went great. I wound up liking it enough to build a belt grinder and mostly use my HSS tools now. 

Getting into details of cutting geometry is much more complex than I expected, but I think I'm understanding it reasonably well so far. I find with these sorts of things I need to read, let it simmer a while, read again, try something, then start better understanding. 

On that line, I think it would help me to see things. Would you be willing to try giving angles to demonstrate better some of the concepts? Then I can make a tool, and see it be better or worse. Perhaps with a common material we hobby users all have like 6061 aluminum or 12L14.


----------



## mikey

ttabbal said:


> Would you be willing to try giving angles to demonstrate better some of the concepts? Then I can make a tool, and see it be better or worse. Perhaps with a common material we hobby users all have like 6061 aluminum or 12L14.



It's coming, Sir. I gave you the angles for my aluminum tool and the square tool is the best mild steel cutter I have been able to make. I will give you the angles for a very good 303/304 SS cutter in my upcoming Mods post. I will tell you what to change and why you want to change it, and I'll tell you how much to change it and how to assess it. 

After I deliver the article and you guys have a few days to think it over, I was going to propose we all design a tool together, on line. We would pick a material group, sort out the characteristics of the material that need to be dealt with and then design a tool to work with that material. It would help you guys to understand the thought process and solidify the concepts. It really isn't hard to do; what is hard is to say it in words.

I swear that if I could get you guys in my grubby little hands for one hour, I could teach you all I know about this tool grinding stuff.


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## ttabbal

mikey said:


> I swear that if I could get you guys in my grubby little hands for one hour, I could teach you all I know about this tool grinding stuff.



You heard it guys, party at Mike's place! BYOBits.  He's covering airfare, so get to the airport and tell them @mikey sent you.  

no?


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## Z2V

mikey said:


> I swear that if I could get you guys in my grubby little hands for one hour, I could teach you all I know about this tool grinding stuff.



Mikey, I think we need at least 2 hrs,,,,,,,


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## mikey

ttabbal said:


> You heard it guys, party at Mike's place! BYOBits.  He's covering airfare, so get to the airport and tell them @mikey sent you.
> 
> no?



You guys are welcome here but airfare, no!



Z2V said:


> Mikey, I think we need at least 2 hrs,,,,,,,



Nah, 1 hour is enough. I don't know enough to fill 2 hours!


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## ttabbal

mikey said:


> You guys are welcome here but airfare, no!
> Nah, 1 hour is enough. I don't know enough to fill 2 hours!



I'm remembering that next time I'm on Oahu.


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## mikey

ttabbal said:


> I'm remembering that next time I'm on Oahu.



You will be most welcome, Trav!


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## ACHiPo

Whew!  It took a few sessions, and quite a few re-readings, but I finally made it through this.  What a fantastic thread!

I got my belt grinder cleaned up and a selection of ceramic belts.  My grinder does not have a platen, so I need to remedy that.  When clicking on a link from this thread I came across graphite canvas as a platen surface.  This would not have the static issue of pyroceram, but presumably gives a bit, so could lead to slight curvature of the tool face?

Here's a pic of the belt grinder I received from a very generous hobby machinist:


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## mikey

Evan, to grind tools you must have a flat platen. I know Pyroceram will stay flat for many years so that is what I use. I have no experience with a graphite coated canvas thing but the forum guys say it give in use. I would use glass instead but it is just one opinion.


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## Aaron_W

The local metal supply has added a bunch of machines making a corner into a sort of showroom for tools. Mostly Jet brand, I saw this 2x42 belt / 8" disc grinder. It is a bit pricey but if it would be good for grinding bits I could start watching for a second hand one, finding a used one can't be any more of a long shot than finding the old Craftsman like you have. 

http://www.jettools.com/us/en/p/j-41002-2-x-42-bench-belt-disc-sander/577004


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## mikey

Aaron_W said:


> The local metal supply has added a bunch of machines making a corner into a sort of showroom for tools. Mostly Jet brand, I saw this 2x42 belt / 8" disc grinder. It is a bit pricey but if it would be good for grinding bits I could start watching for a second hand one, finding a used one can't be any more of a long shot than finding the old Craftsman like you have.
> 
> http://www.jettools.com/us/en/p/j-41002-2-x-42-bench-belt-disc-sander/577004



You might PM @Aukai - he owns one and can give you first hand info on it.


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## mikey

_Sorry this took so long, Guys. I wrote and re-wrote this multiple times, trying to simplify it. I hope this works._

Have you ever thought about what a good lathe tool does? I have. To me, a good tool should do its job without calling attention to itself. If you need it to rough, it roughs well without any annoying chatter. If you need a fine finish it should give it to you simply by angling it toward the tailstock. If you need accuracy, you should be able to dial in what you need and the tool should cut it. This is what all good lathe tools should do, in whichever material you happen to be working with, but they must be designed to do it. You can’t just grind up any old shape and expect it to work well.

Not to overstate the obvious but no tool does it all. Every material group we work with has its own characteristics and if you want your tool to perform well then it has to be designed to accommodate those characteristics. Designing such a tool takes some thought and work but if you do it well then you will have a tool that is all but invisible – it will do what you need it to do without you having to struggle to achieve it.

I know that some of you have ground the Square Tool and have hopefully found it useful. I designed it and I’m proud of it but I know it for what it is – a compromise that works with most stuff but is not great at any one thing; it is an “okay” tool. If it is good enough for your needs then stop here and be happy but you should know that a material-specific tool ground for high performance will easily kick a Square Tool’s butt!

So just what is a high performance, material-specific “good tool”? _It is a tool with a tip geometry designed to minimize cutting forces and cutting temperatures while accommodating the characteristics of a specific material group. _Note that cutting forces and temps comes first, at least in my book, because these tools are intended for use on smaller lathes, maybe 12” and below. I do not need a bigger lathe; I just want mine to cut like one.

Now, as for the material-specific part, each material group has certain characteristics that we need to deal with and we need to know what they are in order to design a tool to accommodate them. I’m not referring to the chemical composition of the material, although that does matter. I am more concerned about other factors:


*Machinability* refers to the ease with which a material can be cut. It is a comparative rating using 1212 mild steel as a standard. Here is an easy to use list: http://www.carbidedepot.com/formulas-machinability.htm. We need know how “hard” the material is to cut because this influences how durable the cutting edge must be. It also influences your choice of blank; it might be better to go with cobalt instead of M2 for tool steels, high carbon steels and stainless steels.
*Work Hardening* –Work hardening occurs when the cutting tool transfers the heat from the cutting operation to the work piece instead of the chips and is aggravated by materials that have low thermal conductivity and retain the heat in the body of the work; stainless steels are an example of such a material. Stainless Steels and many of the higher carbon heat treatable steels will work harden. Sharp tools, rapid chip evacuation and a savvy lathe operator are required for these materials.
*Heat sensitivity *– some materials, especially plastics, are very heat sensitive. If the work gets too hot it tends to melt and that can affect finishes and dimensional accuracy. The tool must cut freely and remove heat as quickly as possible. Aluminum-specific tools work pretty well for most plastics.
*Variations within the material group.* For example, the 300 series of Austenitic Stainless Steels include 303, 304, 316, 316L, etc. All of them will work harden, especially 304 and 316 – they get hard if you look at them sideways. 303, on the other hand, contains Sulfur, which makes it much easier to machine. It will work harden, too, but you can cut it easier so avoiding high temperatures in the cut is simpler. Stainless Steels are not particularly hard in the annealed state in which we usually buy it; it gets hard if we don’t cut it the right way or use sharp tools.
My point is that in every material group there will usually be different alloys. Your job is to know about distinguishing factors in the group that will affect your ability to cut it and design around it.

The more you know about your materials, the easier it is to design the tool to accommodate them. Do your homework, guys.

*Designing a tool*

If you’ve read through this thread this far, you have been exposed to what each tool angle does. We are going to use that knowledge to design our tools. To assist us, I’ve summarized them below:


*Relief angles* – *reduces cutting forces* by improving penetration and *improves finishes*. It also weakens support under the cutting edge and reduces edge life if taken to extremes.
*Side Rake* – the key effects produced by increases in side rake are the *reduction of cutting forces and cutting temperatures* without impacting on support under the cutting edge. It does this by increasing (narrows) the included angle at the cutting edge to enhance penetration, thins the chip, increases chip flow rate, and extends edge life.
*Back Rake* – *reduces cutting forces and cutting temperatures and controls where cutting forces are focused.* As back rake increases, the cutting forces shift closer to the tip.
*Nose Radius* – the bigger the radius, the greater the deflection. Deflection is minimized when the depth of cut exceeds the nose radius.* Therefore, small nose radii are good radii.*
Next, let’s look at a typical angle grinding table. The information in these tables is derived from manufacturing, machining and experiential data collected over many decades and is an industry “standard”.




Note the following:


All the angles change to suit the material type the tool is being ground for. Distinctions are not made for different alloys within a material class; sometimes this matters, sometimes it doesn’t.
The side relief angles are pretty constant; this is where the concept of “clearance is clearance and enough is enough” comes from … Hmmm.
Side relief is greater than end relief. That smaller end relief angle adds mass behind the cutting tip for strength but it also concentrates heat so while the tip is stronger, it cuts hotter. This is why I recommend making the end relief the same as the side relief; you don’t need the mass in a non-production setting and you certainly don’t need more heat in the cut.
Side rake angles vary widely depending on the material class. Note that the side rake for machine steels (higher carbon steels) and stainless steels are higher. This is because greater amounts of side rake clears chips faster and that reduces cutting temperatures, which reduces work hardening. This tells you that the table actually does account for at least some of the known properties of the materials.
Back rake also varies widely but recommends higher amounts of back rake for aluminum and copper. These softer materials are also “sticky” when cut and the higher back rake shears these materials more effectively. Now you see that the table actually understands tip geometry; it just isn’t blatant about it.
One last one. Did you notice that brass and bronze have a side rake range that is slightly positive to slightly negative? Most of us just use Zero rake, and I do it because I’m lazy. I tested tools on brass and bronze with various amounts of side rake and found that brass finishes better with slight positive rake and bronze finishes better (less tearing) with slight negative rake but only when the relief angles are at conventional angles. When the relief angles are increased to about 15°, I saw little improvement in the finishes with changes to side rake in these materials, which is good because as I said, I’m lazy. So, when I make these tools, I use a 15° side and end relief and just hone the top flat – one less surface to grind. It is also interesting to note that a positive rake Square Tool will cut these materials to a very fine finish; there goes the “neutral rake” and the “tool will dig in” argument. Try it and see.
Okay, so now we know that the table sort of does account for the characteristics of each material class and while it is subtle, understanding how the tool angles work allows you to see the nuances contained therein. This knowledge and 5 bucks will get you a Venti Hazelnut Mocha at your local Starbucks!

There is a reason for dragging you through the table discussion. The table gives you two really valuable things: it gives you baseline angle data to begin your angle changes from, and it tells you which materials can potentially work harden (higher carbon steels and stainless steels).

Now you know what the tool angles do and you have some baseline tool angles to consider. Next you need to consider the characteristics of the material you’re going to work with. I’m not going to list the characteristics of every material class for you. You need to research this yourself but we will design a tool for Stainless Steel as an example of the design process.

NB: To possibly save you some work, I’ve already given the angles for my mild steel, brass and aluminum cutting tools in post #36 of this thread if that is of interest to you. You never know; they might just work well on your lathe.

*Designing a tool for Stainless Steel*

*Material considerations:*

Stainless steels are produced in a large variety of alloys. Perhaps the commonest group of SS is the Austenitic group, the 300 series: the most commonly used SS is probably 316, followed by 304. The easiest alloy to machine is the Sulfur-bearing 303; this is a good choice for hobby guys to use.

The 300 series is not really that hard in the annealed state. If you look at the machinability chart you will see that 303 has a rating of 78%, while 304 is about 45% compared to 1212 mild steel at 100%. So, 303 is only slightly harder to cut than mild steel and 304 is about twice as hard to cut. The cutting speed for the Austenitic group is about 120 SFM for HSS tooling so again, not that hard to cut. It can actually be a little “gummy” and will tend to produce stringy chips.

Again, the one characteristic we need to be aware of is the tendency for SS to work harden. Basically, if the work heats up too much at the point of cut the surface will form a hard layer that can be very difficult to cut, much less take a finish cut. You have to get under that layer to cut it if it forms so we need to avoid work hardening when possible. To minimize work hardening, use a good tool and avoid dwelling in the cut. We can discuss how to cut SS in more detail if there is interest.

*SS Tool Design*

Now we know that we need to focus on reducing cutting forces to produce a tool that will move through our SS with relative ease while also getting the chips out of the cut fast to avoid work hardening. We also know we intend to alter the standard tool angles in the table to do this. The question is* how do we change them and by how much?*

The answer is based on my experimental data. I apologize but this is all I have to go on; there is no published data beyond this recommendation as far as I know. My method is to add 25-40% to the standard baseline angles and base the specific amount on your priorities. For example, if the material is soft then you can increase the relief angles by 40% without worrying about edge life but if the material is hard, like tool steel, then you may want to leave the relief angles at baseline and try reducing cutting forces with your rake angles. It’s a judgement call that will later be tested in a cut.

Sorry guys, I know this sounds nebulous. The best advice is to start low, say 25%, then increase it until you either get the result you want or things get worse. Over time, you will learn the judgement you need to adjust things with confidence. You will also find that this 25-40% range works rather well. Going above 40% usually doesn’t provide much benefit; it tends to lead to premature wear, especially in harder materials. There are also times when going past 40% makes sense; I do this if the tool keeps cutting better and better without going dull too fast. Usually this is on soft stuff like plastics.

Keep in mind that when we change an angle to produce a desired advantage, it will produce that advantage. But if we change another angle the effect is additive; each angle change augments the effect of other angle changes. In other words, no tool angle works in isolation. If you change one, it affects them all. This is a good thing, by the way, and it is good to know that a change here and a change there adds up to a lot so you do not need to go hog wild with your angle changes. Go slow, be conservative, and base further changes after you assess how well the tool cuts. After you have some experience with this tool angle change thing I think you will be very surprised to see how even a degree or two can produce BIG results.

*Okay, now we can get to designing our tool*

Tool angles from the table: Side relief: 10°, End relief 8°, Side rake 15-20° and Back rake 8°.

What these angles tell you is that a conventional tool attempts to deal with the work hardening tendency of SS by using the rake angles – smart. The remainder of the angles are rather ordinary – not so smart.


Relief angle considerations: Since SS is not that hard we can add a bit more relief angle to reduce cutting forces without worrying too much about affecting edge life. We need not go overboard with this because the effect of our rake angles will be additive to whatever we do with the relief angles. For this tool, a 40% increase will do, so we can make the side and end relief 14° but 15° will work better with minimal impact on strength.
Side rake: side rake is the key angle here because it reduces both cutting forces and cutting temperatures in a single stroke. If we use 40% of the standard 20° we would have 28°, which is just about right.
Back rake: standard amounts of back rake will put the cutting forces at the side cutting edge, which is fine, but if we increase back rake it will assist in chip thinning, reduce cutting forces and will also accelerate chip flow to reduce cutting temperatures even more. It will also put the cutting forces closer to the tip, which is where a smaller lathe will apply power during a roughing cut. Let’s add a full 40% of the standard 8° to give 12° of back rake.
So, if we hold to the recommended 25-40% increases over standard table angles we could grind our tool with *15° relief angles for both side and end, 28° of side rake and 12° of back rake.* Our tool will have adequate support under the cutting edges and pretty large amounts of side and back rake to get the chip out of the cut quickly to reduce cutting temperatures and cutting forces will be reduced significantly. Note that these angles are a guess on my part but based on past experience, it’s a pretty good guess. If I were a new guy, I would start with a 25% increase for each angle and work my way up until the tool cut really well. There is no magic number or formula.

I would use a 1/64” nose radius on this tool to minimize deflection. The reasoning is that too large a nose radius will tend to deflect with smaller depths of cut and if it deflects it won’t cut and if it doesn’t cut then it builds heat and if it builds heat then it work hardens and then we can’t take a finishing cut. Whew!

And that is how you design a tool for Stainless Steel – Toldja’, not that hard!

*How to test your tool design*

When I design a tool that I’ve never made before, I grind one blank to the conventional angles in an angle table and put my modified angles on another blank or on the end opposite the conventional one. I keep careful records on depth of cut, speed and feed, then push the conventional tool until it chatters. Then I do sizing cuts and then finishing cuts. Once I know how that conventional tool works and I am sure of its limits, I test the modified tool.

Usually, I will grind the modified tool with conventional angles except for one single angle. Typically, this will be a modified relief angle. Then I push that tool hard and record the results. I often start the modified angle at about 25-30% and increase the amount if the edge holds up well. If I can take a cut deep enough to chatter and the edge remains razor sharp then I consider that optimized. Sometimes I will go beyond 40% if the edge is holding up well. If you later notice that your side edge is dulling in use, go back to your notes and reduce the relief angles on the next tool.

Once I get the relief angle optimized, I move on to modifying side rake alone, then modify back rake. What I am looking for here is to see how much deeper I can cut before the tool chatters or the lathe bogs down. Do not be surprised if your modified side and back rake allow you to double the depth of cut over a conventional tool. I also watch to see if the chips clear faster and better and also if the chips thin as expected; they should. I consider rake angles optimized when I can at least double the depth of cut over that of a conventional tool. If the tool is for a material that work hardens, then it must be able to exceed the depth of cut that causes the conventional tool to chatter at the very least; your tool should easily make that same cut without chatter and without work hardening. Typically, your cutting edges should be as sharp as they were at the start of the cut.

How do you assess whether the tool reduces work hardening? You take a decent depth of cut and keep the tool cutting continuously. Then you take a fine cut with a relatively slow feed, maybe 0.005” deep, and the tool should shave off a chip with a fine finish. If it does this, that work surface is not hard and your tool angles worked. You can also test the work for hardness with a hardness file and compare it to an un-cut piece.

I always start with a very small nose radius, one I can just see with the naked eye, then increase it until it gets to about 1/32” so I can see how the tool cuts with that large a radius. To me, 1/32” is a big radius and I try hard to keep it smaller if I can. For soft materials like Aluminum, brass or plastics a larger nose radius is okay but for steels, I usually go with 1/64”.

Once you feel comfortable that you’ve optimized your tool angles and you’ve actually done some practice pieces and know that the tool works well then grind a keeper from a blank you trust and you’re done. It may take me several months to get to this point but I know that my keeper tool is going to be a “good tool”.

As I said, this is not hard to do. It requires work and thought but you will end up with a tool that is unique, and you will know exactly why it is ground the way it is. Moreover, if something goes wrong with it down the road, you will know exactly how to address it.

Trust me; one day you will rough out a work piece, then size it quickly and then take a micro-cut to come in on size. You’ll notice that the finish is really fine and the lathe and tool handled everything without effort. Then you’ll realize that you didn’t even stop to think about the tool once; you just made your cuts and the tool cut. On that day, you’ll know that you designed and ground a really good tool.

*End Notes:*

Guys, there is something about a 15° relief angle that just works. I don’t know why this is; it just works. I’ve done thousands of test cuts in all sorts of materials and somehow, that 15° relief angle is almost always where I end up. It reduces cutting forces nicely and stays sharp over time. I also tested relief angles for threading tools and 15° produced burr-free threads and held up in just about every material I’ve used it on, including tool steels. I tested angles above and below 15° for threading tools but this angle cuts really well and holds up the best. Whenever I need to grind a new tool for some material I haven’t cut before, I will start low and dial in the relief angles but somehow I end up with 15° as the best setting … dunno’.

I know this is a lot to absorb but while tedious in words, it is not difficult. It may look that way but it really isn’t. It is the only way I know of to grind a tool that will work on your specific lathe with you in the driver’s seat and I encourage you to try it.

I hope this helps you. If you have questions, I am here.



Mike


----------



## TTD

Awesome post (as usual), Mikey.

Being relatively new at grinding cutting tools (at least properly, anyways), I’ve still got a while to go yet before all of this becomes “second-nature”. Not knowing any better when I first started out a couple of years ago, I used to think that as long as only the tip of tool was touching the work  & nowhere else was rubbing, that I was good to go. In fact, NONE of my tools back then even had any back rake…just “a bit” of side rake & side/end relief.

Now, thanks to this thread, I can see the errors of my ways & I’m starting to actually visualize in my mind what’s happening at the tool tip while cutting. Started paying more attention to tool geometry instead of the “that’ll-be-good-enough” mindset & the difference has been (no surprise) night & day.

I, and more importantly my wee lathe, can’t thank you enough Mike for taking the time to explain all of this so even dummies like me can understand it. It is immensely appreciated, my friend! Hands down, the best tutorial out there for beginners learning to grind their own tools.


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## mikey

Thanks, Todd. What a nice way to start my day!


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## ttabbal

Thanks again @mikey! I'm going to try your design method out on some 304 SS, just because I have some. 

A couple questions I've bumped into that might be helpful for everyone to see answers to... 

1) I see why turning the tool toward the tailstock helps with finish, but what about when you are turning to a shoulder on the left? Would it be better to make a tool for this? Perhaps by increasing the angle on the left, decreasing on the right to mimic the tool post angle change? 

2) Stringy chips. I've had some of this on 6061 in particular. You can break them by stopping the cut, but is there more we can do to help them break on their own? I know chip-breakers can become a whole new topic, but perhaps a couple ideas for one material would be appropriate? 

3) Tip radius. I made some using the belt grinder, but they aren't that consistent. Tend to be larger at the tip, and thin out toward the bottom. It works, as the top is where the cutting happens, but I would like to be more consistent to make measuring easier. The diamond cards are a bit slow to cut this. Would a light touch with a file be a good idea? Perhaps some sandpaper on a flat surface?


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## ttabbal

I'm putting this in a different post to try to keep things organized.. I need to turn some cast iron for my collet chuck. It doesn't seem to have a hard surface, which I read can be a problem. Sadly, I don't have scraps to work with, so testing will be a little limited. I was leaning toward just taking a light cut for testing, as I only need to remove about 0.1". 

Tool angles from the table: Side relief: 10°, End relief 8°, Side rake 12° and Back rake 5°.

This puts them in range of the 15° square tool, with a lower back rake. I read it tends to cut a bit dusty, and can be a bit abrasive. So I'll cover the ways and use a vacuum to keep dust down. I was leaning toward doing 15/15 on the side/end. This is to a shoulder on the left, so the previous post's question about that will come into play here. I'm leaning toward going to 15 on the side rake, 8-10 on back rake. 15 mostly so I can be lazy and not adjust the table angle.  Increasing the back rake to move cutting forces toward the tip, as like most here, I have a small lathe.   

My lazy side wants to toss a 15° square tool in there and give it a go. I suspect it would cut reasonably well. Perhaps not ideal, but it IS a one-off. I don't anticipate turning much cast iron. Of course, now that I've said that, I'll need to do a ton of it.  

What do you think Professor Mike? Am I heading the right direction?


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## DHarris

GREAT write-up Mikey! 

Ok, I've taken this latest chapter and placed it at the end of the text book (we are now at 37 pages).  I've attached it to this post for Mikey to review and let me know if there is a better "order" for the flow of the document.  Let me know what changes to order of topics you would make, and I'll make them - format the document better (page breaks & text flow around photos / diagrams etc) and post a final version to this thread.

All input welcome

p.s.  and I'll make a table of contents in the front from the highlighted titles.

edit:  file is in an older version of MS word - so everyone should be able to open it up.


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## mikey

ttabbal said:


> A couple questions I've bumped into that might be helpful for everyone to see answers to...
> 
> 1) I see why turning the tool toward the tailstock helps with finish, but what about when you are turning to a shoulder on the left? Would it be better to make a tool for this? Perhaps by increasing the angle on the left, decreasing on the right to mimic the tool post angle change?



If you use a general purpose shape, like our Square Tool shape, then it will cut into a shoulder with no problem. When doing so, you are taking light cuts with the nose radius and end cutting edge. The tool angle is the same as you would use for a facing cut. Usually you will cut with the end edge until you hit the shoulder and then face out.



ttabbal said:


> 2) Stringy chips. I've had some of this on 6061 in particular. You can break them by stopping the cut, but is there more we can do to help them break on their own? I know chip-breakers can become a whole new topic, but perhaps a couple ideas for one material would be appropriate?



Certain materials, most notably aluminum and stainless steel, will string. This is especially true when we take light cuts. It has to do with the higher ductility of the material - thin chips don't break off; they string. You can break them by taking heavier cuts at higher feed rates or you can pause momentarily in the cut. Unfortunately, light cuts will string and that is just the way it is. If you use a carbide insert with a chipbreaker it can help but you have to take a heavy enough cut for the chipbreaker to work so what do you do when you have take light cuts? You string, plus you will have issues with accuracy when taking finishing passes. There is no perfect answer, sorry.



ttabbal said:


> 3) Tip radius. I made some using the belt grinder, but they aren't that consistent. Tend to be larger at the tip, and thin out toward the bottom. It works, as the top is where the cutting happens, but I would like to be more consistent to make measuring easier. The diamond cards are a bit slow to cut this. Would a light touch with a file be a good idea? Perhaps some sandpaper on a flat surface?



For me, the fastest way to cut an accurate nose radius is with a coarse diamond stone. I cut a flat with it using firm pressure, then switch to a fine or extra-fine stone to round and blend the edges. It takes me maybe 60-90 seconds from start to finish. I can do it with a fine grit belt if I'm careful but I prefer the diamond stones - far more likely to give me an accurate radius. It would be unlikely to have a file cut hardened HSS but a sandpaper might work - see you in about a year or so. All kidding aside, use the diamond stones.


----------



## mikey

ttabbal said:


> I'm putting this in a different post to try to keep things organized.. I need to turn some cast iron for my collet chuck. It doesn't seem to have a hard surface, which I read can be a problem. Sadly, I don't have scraps to work with, so testing will be a little limited. I was leaning toward just taking a light cut for testing, as I only need to remove about 0.1".
> 
> Tool angles from the table: Side relief: 10°, End relief 8°, Side rake 12° and Back rake 5°.
> 
> This puts them in range of the 15° square tool, with a lower back rake. I read it tends to cut a bit dusty, and can be a bit abrasive. So I'll cover the ways and use a vacuum to keep dust down. I was leaning toward doing 15/15 on the side/end. This is to a shoulder on the left, so the previous post's question about that will come into play here. I'm leaning toward going to 15 on the side rake, 8-10 on back rake. 15 mostly so I can be lazy and not adjust the table angle.  Increasing the back rake to move cutting forces toward the tip, as like most here, I have a small lathe.
> 
> My lazy side wants to toss a 15° square tool in there and give it a go. I suspect it would cut reasonably well. Perhaps not ideal, but it IS a one-off. I don't anticipate turning much cast iron. Of course, now that I've said that, I'll need to do a ton of it.
> 
> What do you think Professor Mike? Am I heading the right direction?



As usual, the answer is more complicated that just tool angles. Cast iron comes in a variety of alloys and this matters - a lot. If your plate is grey cast iron then it machines readily. Ductile cast iron has higher strength and is a bit harder to cut. There are several other alloys that I haven't machined before so I cannot advise you there. The problem for me has been consistency in the material, or lack thereof. Chinese CI is not usually of high quality and can have soft and really hard spots throughout the casting. Unfortunately, it is the most readily available and the cheapest. European CI is usually pretty consistent. USA CI is also usually pretty good  to very good.

I normally use a HSS tool to cut CI but I have also used carbide inserts with TIN coating and they worked well. I prefer HSS because I can keep the tool sharp. I also use cobalt HSS, not M2. The machinability rating for CI varies with the alloy but in general, it is about 45-50%. Bear in mind that this material is abrasive so in addition to being harder, it tends to grind down edge. That is why I tend to use cobalt. It is also why I tend to be more conservative with my relief angles. 

I cannot find my CI tool to measure the angles but my records show that it had 12 degree relief angles to contend with the hardness and abrasion. When turning CI with a cobalt tool, I tend to go slower (about 60SFM) so cutting temps are not that big an issue but cutting forces can be huge so I did increase side rake to 15 degrees. Back rake was 10 degrees on my tool. My records show that I was concerned about a built up edge but I didn't go into more detail (and I can't remember that far back). Regardless, the tool cut backplates well. 

I will need to grind another CI tool soon because I have some backplates to do, too. I will very likely put some thought into it but I will probably end up close to these numbers. Sorry to be of so little help. I do agree that a Square Tool will probably work but the only way to tell is to try it. If the edges wear too fast, switch to cobalt.


----------



## ttabbal

mikey said:


> If you use a general purpose shape, like our Square Tool shape, then it will cut into a shoulder with no problem. When doing so, you are taking light cuts with the nose radius and end cutting edge. The tool angle is the same as you would use for a facing cut. Usually you will cut with the end edge until you hit the shoulder and then face out.




Ah, hold it like a facing cut was the bit I missed. Thanks! I kept visualizing trying to come into a shoulder with the tool post angled toward the tailstock, so the shoulder might well hit the tool or the tool post before the cutting edge got there. I knew that couldn't be what you were saying to do. 




mikey said:


> Certain materials, most notably aluminum and stainless steel, will string. This is especially true when we take light cuts. It has to do with the higher ductility of the material - thin chips don't break off; they string. You can break them by taking heavier cuts at higher feed rates or you can pause momentarily in the cut. Unfortunately, light cuts will string and that is just the way it is. If you use a carbide insert with a chipbreaker it can help but you have to take a heavy enough cut for the chipbreaker to work so what do you do when you have take light cuts? You string, plus you will have issues with accuracy when taking finishing passes. There is no perfect answer, sorry.




I suspected that might be the answer, but I wanted to make sure I wasn't missing anything obvious. Strings aren't the end of the world, just have to be a little more careful around the machine when they are present. And try not to let them get into the cut, messing up my finish. I see why 12L14 is so popular. I can cut that with near anything and get nice easy chips. 




mikey said:


> For me, the fastest way to cut an accurate nose radius is with a coarse diamond stone. I cut a flat with it using firm pressure, then switch to a fine or extra-fine stone to round and blend the edges. It takes me maybe 60-90 seconds from start to finish. I can do it with a fine grit belt if I'm careful but I prefer the diamond stones - far more likely to give me an accurate radius. It would be unlikely to have a file cut hardened HSS but a sandpaper might work - see you in about a year or so. All kidding aside, use the diamond stones.




I'm blaming lack of coffee for the idea of using a file on HSS.  I forget how hard these things are, the belts just cut them so quickly. 

Push harder with the coarse diamond, got it.  I tend to be a little too gentle on the honing pressure.


----------



## mikey

DHarris said:


> GREAT write-up Mikey!
> 
> Ok, I've taken this latest chapter and placed it at the end of the text book (we are now at 37 pages).  I've attached it to this post for Mikey to review and let me know if there is a better "order" for the flow of the document.  Let me know what changes to order of topics you would make, and I'll make them - format the document better (page breaks & text flow around photos / diagrams etc) and post a final version to this thread.
> 
> All input welcome
> 
> p.s.  and I'll make a table of contents in the front from the highlighted titles.
> 
> edit:  file is in an older version of MS word - so everyone should be able to open it up.



Thank you for doing this, Dave. I don't know, your order looks good to me. I would imagine that you and the guys would be a better judge of what you would like to see so I'll leave it to you guys.

I sure have been verbose but sometimes it take more words to make things clear for new guys and I wanted to make sure that I reached as many people as possible. I'm glad the bulk of the writing is done and I should be able to turn most of this thread over to you guys to discuss, show your tools and report your successes. 

Sure has been an enjoyable thread for me, though!


----------



## ttabbal

mikey said:


> I will need to grind another CI tool soon because I have some backplates to do, too. I will very likely put some thought into it but I will probably end up close to these numbers. Sorry to be of so little help. I do agree that a Square Tool will probably work but the only way to tell is to try it. If the edges wear too fast, switch to cobalt.




It's never as simple as we would like.  

It looks like a basic grey cast, but it is an import (Shars) so it could have issues that way. Come to think of it, I don't think I actually have any cobalt bits. Need to look for some for when I need it. I think I'll give my M2 bits a go and if they don't make it I'll switch to carbide. The post was mostly to see if I was understanding the concepts enough to adjust to a material I had in front of me. Your notes were close to where I was going, so I will feel good about that and keep learning.


----------



## mikey

ttabbal said:


> It's never as simple as we would like.
> 
> It looks like a basic grey cast, but it is an import (Shars) so it could have issues that way. Come to think of it, I don't think I actually have any cobalt bits. Need to look for some for when I need it. I think I'll give my M2 bits a go and if they don't make it I'll switch to carbide. The post was mostly to see if I was understanding the concepts enough to adjust to a material I had in front of me. Your notes were close to where I was going, so I will feel good about that and keep learning.



Pretty sure I sent you a Mo-Max cobalt bit some time back.


----------



## ttabbal

mikey said:


> Pretty sure I sent you a Mo-Max cobalt bit some time back.



Oh! I had to go look, I thought they were all M2, though nicer than the bulk pack I've been using. Turns out you are correct, you did include a cobalt bit. Go you! 

I also remembered that I picked up some 1/2" bits that appear to be made from this stuff... 

http://www.matweb.com/search/datasheettext.aspx?matguid=8835250a8db649beae12dd1ba89b1604


----------



## mikey

ttabbal said:


> Oh! I had to go look, I thought they were all M2, though nicer than the bulk pack I've been using. Turns out you are correct, you did include a cobalt bit. Go you!
> 
> I also remembered that I picked up some 1/2" bits that appear to be made from this stuff...
> 
> http://www.matweb.com/search/datasheettext.aspx?matguid=8835250a8db649beae12dd1ba89b1604



T15 - fun to grind but pretty abrasion resistant. It should work well for your CI project. I suggest you use a new ceramic 35 grit belt and lean into it a bit more when you grind. Once you get it to cut, keep going because if it cools it will be harder to get it going again. I really like T15 for stainless steel tools.


----------



## jwmelvin

Mikey, I appreciate your explanations and guidance, thank you. I have a couple questions:

Can you point me to theory regarding the relief angles and how they play into cutting forces? Although they do not go into any degree of detail, the slides here and here do not describe the cutting forces as dependent on the relief angle. I know you said you did not want to get into some of this; perhaps the answer is that Merchant's assumption does not hold (or depends on small relief angles)?

In post 652, you describe work hardening as a result of temperature. I've always understood the phenomenon as strain-induced hardening (as reflected on Wikipedia or here). If possible, I'd like to better understand the underlying principles and conditions that induce work hardening when cutting. Sharp tools seem like they would help by minimizing deformation in the workpiece. As a practical matter, I understand that taking sufficiently large cuts will avoid the issue.


----------



## ttabbal

mikey said:


> T15 - fun to grind but pretty abrasion resistant. It should work well for your CI project. I suggest you use a new ceramic 35 grit belt and lean into it a bit more when you grind. Once you get it to cut, keep going because if it cools it will be harder to get it going again. I really like T15 for stainless steel tools.



So not like the normal HSS where you don't want to let it get too hot? Do I need heat protection to grind this stuff? M2 gets pretty toasty at times while grinding.


----------



## Bob Korves

ttabbal said:


> So not like the normal HSS where you don't want to let it get too hot? Do I need heat protection to grind this stuff? M2 gets pretty toasty at times while grinding.


Decent HSS can be heated to a dull red with very little loss of hardness.  Higher cobalt tool steels can run red hot all day.  Do not worry about some colors coming into the metal while you are grinding it or using it.  It will make little or no difference.


----------



## ch2co

A veritable masterpiece.  Thank you Mikey and all of the other contributors.


----------



## mikey

jwmelvin said:


> Mikey, I appreciate your explanations and guidance, thank you. I have a couple questions:
> 
> Can you point me to theory regarding the relief angles and how they play into cutting forces? Although they do not go into any degree of detail, the slides here and here do not describe the cutting forces as dependent on the relief angle. I know you said you did not want to get into some of this; perhaps the answer is that Merchant's assumption does not hold (or depends on small relief angles)?
> 
> In post 652, you describe work hardening as a result of temperature. I've always understood the phenomenon as strain-induced hardening (as reflected on Wikipedia or here). If possible, I'd like to better understand the underlying principles and conditions that induce work hardening when cutting. Sharp tools seem like they would help by minimizing deformation in the workpiece. As a practical matter, I understand that taking sufficiently large cuts will avoid the issue.



Now we're getting into an area that gets complicated. First of all, the Merchant Equation essentially addresses the relationship between the rake angles, shear plane friction and shear plane angle. It does not address the relief angles. Second, it applies to the Orthogonal cutting model where cutting forces are applied perpendicular to the work surface, whereas our tools are actually Oblique cutters where the cutting forces and rake forces are applied at an angle. While the impact of the rake angles on the shear plane applies, the Merchant Equation does not. Well, it does but only when it is modified.

To my knowledge, the relief angles are essentially viewed as clearance angles in the literature. Unfortunate because they matter. I looked for some reliable model regarding the relief angles and found little so I based my understanding on what I could prove at the bench; I had no other option. I took a conventional tool and measured the power required to move that tool through a cut, then varied only the relief angle and measured power with each cut. I no longer have the numbers available but essentially what I found is that as the relief angle increases the power required to move the tool through the cut decreases. The amounts are small but they are there. What is interesting is that on a Sherline lathe, where the carriage is moved by turning a hand wheel at the end of the lead screw, you can feel a difference in the force required to move that tool through a cut when you compare a conventional tool with a high relief angle tool.

I'm sure there is some cutting model out there that addresses this but I am just not aware of it, and I looked hard. What I can say is that there is a lot more to the relief angles than just clearance. What's more, if you look at the finish produced by a conventional relief angle and compare it to that produced by a modified relief angle, there is a definite improvement in the finish produced by the modified tool. If relief is only for clearance then you would not expect an improvement. At this point, I've decided that I'm okay with what I know to be true, although I would be even happier with a model that explained it.

You have to understand that the vast majority of the information on the net applies to carbide tooling, not HSS. There is a lot more available now than when I looked at this stuff initially. In fact, the net was rudimentary back then so the only option available to me was to look at books and to sort it out at the bench. What actually happened was that I derived most of my conclusions by what I could measure and by the results I saw at the lathe. Then I tried to find models that explained what I saw and discovered the Merchant Equation, which explained what I was seeing with the rake angle mods I did. I couldn't find anything about the relief angles. There is a LOT of stuff on the cutting forces; look it up.

With regard to the cutting temperatures, Kennametal describes it thus:
*Work hardening ... is caused when heat generated by the cutting tool transfers to the workpiece material and causes plastic deformation. The process is similar to a heat treatment of the workpiece but on a lower scale.*

Essentially, what is happening is that the lathe tool is generating enough heat to harden the part at the point of cut. The thing to focus on is that while the tool is generating the heat, how that tool is used is just as, if not more important than, the tool itself. Hence, the tool must be sharp, it must efficiently remove the chips and it must be kept moving continuously. Anytime the tool stops cutting while in contact with the work elevates temps and this includes taking light cuts with a nose radius that deflects instead of cutting.

You will find that working with stainless or other potentially work hardening material is something you have to do from time to time. I work with a lot of stainless and have no issues with HSS tools; I do have problems with carbide inserts at times, though. To save my fingers, here are some tips I wrote in another thread:

Mount the work piece as rigidly as the lathe allows. Keep work extension as short as possible and use a live center when needed.
Mount the tool as rigidly as possible, keeping extension of the tool to a minimum.
Use tools with smaller nose radii to reduce deflection. If the tool deflects, it does not cut and if it does not cut it will build heat.
Use tools with high positive rake to enhance chip clearance so that the heat goes out with the chip. 303 has high ductility so chips do not break easily; they string. Even so, getting the chips out fast removes heat and high positive rake tooling does this.
Use sharp tools. For me, HSS with larger side and back rake angles works well. I don't use carbide for this material, although that is certainly not an industrial practice. I opt for cobalt tools that handle higher heat better and I keep the tool sharp.
Use lubricants. I prefer sulfur-bearing cutting oils but have found AnchorLube to work well. This is not so much to cool the cut; it is more to lube the cut without boiling away.
Attend to cutting conditions. The smaller the lathe, the more important this becomes. The speed, depth of cut and feed have to be adjusted to allow the tool to cut continuously; if you dwell in the cut then heat builds and the work hardens. Stainless, especially Austenitic steels like the 300 series, is not particularly hard so cutting speeds in the 100-120 SFM range is recommended but I have found that on smaller lathes it is better to go slower so that we can keep up with the feeds. I normally use 60 SFM. Depths of cut need to be realistic and applicable to the lathe in use; smaller lathes require smaller depths of cut in order to keep feed consistent. Feeds in industry may be measured in IPM but that is meaningless to a hobby guy who is cranking manually; here, our speeds and depths of cut have to be adjusted to enable us to turn the wheel at a consistent and achievable rate and that comes with experience.
The final thing I can think of is to use a steel that is easier to cut. 303 is the sulferized version of 304 and cuts better. 416 does not contain nickel and is much easier to machine than the 300 series.
I hope this answers you. Your tools are important, yes, but you are *more* important.


----------



## mikey

ttabbal said:


> So not like the normal HSS where you don't want to let it get too hot? Do I need heat protection to grind this stuff? M2 gets pretty toasty at times while grinding.



As Bob said, HSS can get hot without concern. What I meant is that the high Tungsten content of T15 takes more pressure to grind it. Once you cool it, it seems to get even harder so getting it to cut again takes even more pressure before it starts to cut again. I use Vasco Supreme bits that are T15 and they are superb bits but grinding them is a bit of a chore. Once I get the belt cutting it well, I don't let up until I have to. Don't worry; it isn't alien steel and you grind it like any other cobalt tool. Just use more pressure and you'll be fine.


----------



## mikey

ch2co said:


> A veritable masterpiece.  Thank you Mikey and all of the other contributors.



Thank YOU! We have an extraordinary bunch of guys here and its been a load of fun.


----------



## ttabbal

mikey said:


> As Bob said, HSS can get hot without concern. What I meant is that the high Tungsten content of T15 takes more pressure to grind it. Once you cool it, it seems to get even harder so getting it to cut again takes even more pressure before it starts to cut again. I use Vasco Supreme bits that are T15 and they are superb bits but grinding them is a bit of a chore. Once I get the belt cutting it well, I don't let up until I have to. Don't worry; it isn't alien steel and you grind it like any other cobalt tool. Just use more pressure and you'll be fine.




Hmmm... I could swear I heard somewhere not to let the tool get too hot when grinding to avoid messing with the hardening/tempering. By "don't let up until I have to" do you mean till it's hot enough to burn you? Or do you hold it another way? With M2 I've just been dipping it in water perhaps more often than needed to keep it cool. Mostly to keep my fingers unburnt, but also to avoid getting the bit too hot. Sounds like that part was not needed. I'd still prefer not to burn my fingers too much though, that's what welding is for.  

I suppose I could use welding gloves, but that seems dangerous around spinning things. I think I'd prefer using a jig of some sort to hold the bit if it comes to that. As usual, I'm probably overthinking it and need to just go fire up the grinder. 

I have 36 grit ceramic belts, and wax lube for them.


----------



## mikey

I would just dip the tool if the tool gets too hot to hold and not worry about it.  The advice about not getting the tool too hot usually comes from wood turners. Many of them used carbon steel tools, although HSS is much more common nowadays. In any case, dip it. There is some concern about micro-fracturing but I haven't noticed any degradation in performance from dipping my tools. 

I hold the tool bit with my bare hand but I use a glove on the other side, the one next to the belt. I know I shouldn't but I've been cut to the bone too many times not to. When using AO belts, the tool gets really hot because the belt doesn't cut efficiently but ceramic belts cut so fast and cool that I don't need to dip the tool, even though I do in between faces. Your results may vary so if it gets hot, just dip it and cool it. There are no rules when grinding other than to do it as safely as you can. Personally, I think that you should do what works best for you and ignore bozos like me.

T15 is harder to grind. It takes more pressure to get it up to the temperature where the belt starts to cut well so once I get the belt working well, I keep it up until I'm either finished or close to it and then I look at where I am. If I need to further, I go further but I don't dip it unless I can't hold onto it due to heat; that's rare.


----------



## Bob Korves

HSS tools, including the higher cobalt versions, were developed specifically for good high temperature hardness.  They quickly replaced high carbon tooling when users learned how heat tolerant they are.  Don't get me wrong, you can burn them up, but you will have to work at it.  The heat of grinding the tool is not an issue.  Dunking it in cold water can cause micro cracking, like Mikey said.  Only cool them enough to get them ground.  It is a good idea not to leave stress risers in the finished tool.   Some blue, brown, or purple color on the tool after grinding does not give problems when you use the tool.


----------



## jwmelvin

mikey said:


> I hope this answers you. Your tools are important, yes, but you are *more* important.



Very helpful, thanks.


----------



## Aukai

Had fun catching up....


----------



## mikey

Okay, it's been a few days and I hope you guys have had a chance to determine if you understand this tool angle and tool mod stuff. I just re-read it and there is a LOT there. I wrote it so I do understand it but something tells me that a lot of you do not. It's okay, I totally get it. Unfortunately, I don't know how to make it simpler than I did. Tool geometry is the key to lathe tool performance and if you want to grind high-performance tools then you need to understand this stuff. If something is not clear, then ask.

The other way you can do this is if I just give you the angles. I know that most of you should be able to grind a tool to specs by now. So far, I have given you the tool angles for mild steel, brass, aluminum and stainless steels. Not much left to cover - just the harder steels - but rather than just give you numbers, I would prefer we take a look at these steels and work out a design that one or some of you can grind and test. It really is simpler than it looks. 

Heh, heh, so if you want a tool to cut tool steel or higher carbon steels then this is how you get it. You jump in so we can uncover confusion points and clear them up. Then pick a material and lay out the characteristics we need to accommodate. Then we'll design a tool together, meaning you choose the tool angles and I'll guide you but I will not tell you. If someone is willing to grind it up and test it, we can tag along and make suggestions for improvement and that would be an incredible opportunity for all of us. 

We do not have to do this if you are not so inclined. However, it is the only way to have me there to look over your shoulder to make sure you're going in the right direction. So I will leave this to you and you guys can decide how you wish to proceed. 

By the way, I talked this proposal over with Bonehead before I wrote the above message. His reaction was really interesting because his default is "snarky" but not tonight. He said that he has come to enjoy the responses and questions that have come up in this thread, many of which he had himself when he was learning to do this. He especially enjoyed seeing the tools that you guys have ground and sincerely congratulates you all. I again tried to get him to join the forum but he just flipped me off when his wife wasn't looking! In any case, with regard to my proposal above, he said, "Good idea. How else they going learn?" Seven Pidgin English words in a row is a lot for him so, with his approval, my offer stands.


----------



## ttabbal

I have to admit, I want to meet bonehead. Sounds like a fun guy. If I make it out there, I'm buying you both a beverage. 

I don't have anything harder here. But I like the idea. I kind of went that way with cast iron. I ground up a T5 bit but haven't cut with it yet. I'll add a pic just for fun. It's a basic 15 degree square tool with about 10 degrees back rake. I was lazy and didn't want to reset the table angle. 

Have to really push that T5 into the belt..


----------



## mikey

Toldja' that T15 needs some pressure to cut. The edge holds up for a looong time, though, and it will handle CI well if you get the angles right. You certainly have the grinding down, Travis - good for you!

We're more likely to catch Bonehead in Vegas - he goes there so much he should file for residency in Nevada. He tells me he enjoys gambling but I suspect he is just trying to keep his wife occupied so she stops nagging him.


----------



## ttabbal

Thanks for all the help Mike! Great thread here. I'm going to need to download and print a new copy of the Book of Mike. 

I also discovered that my honing is improved, I found a few shallow cuts on the thumb I used for testing the edge and cleaning the crud off so I can see the edge. Going to need to switch to a paper towel for cleaning.  I knew I should, but I didn't expect it to be that sharp. My grandfather would slap me upside the head, he taught me sharpen knives safer than that.


----------



## ttabbal

Took a first pass. Not bad... 





And my tool is apparently magnetic...


----------



## mikey

I almost always have small unintentional cuts somewhere after honing. My tools are pretty sharp when I'm done and I usually don't feel cuts; I just see blood on the tool.  

CI induces a magnetic field when cut so yeah, the splinters will stick on like that. I use a demagnetizer when it gets to the point where it bugs me.

You need to play with the speeds and your tool's lead angle. There is a combination that will produce a really nice finish but still cuts well. Every tool is different so you need to mess with it.


----------



## ttabbal

You're not kidding about durability. I can see why you would like it on stainless. I can't tell any difference on the tool after the work. Not that it really did all that much work, just turning that center diameter down about 0.1". I did mess with speeds and angles and got a nice finish on the CI. The chuck is mounted on it now and running very well. 

If people want to do the @mikey tool bit challenge, let's pick a material and I'll get some to practice on and grind the test bit. Would 4140 be a good choice?


----------



## mikey

4140 would be a very good choice. It is commonly used in a hobby shop.

1144 is also common; if you have not worked with 1144, you should try it.

Or you can go with O-1 tool steel or whatever.

T15 has a good amount of Tungsten in it so it can run at pretty high temperatures and is abrasion-resistant. The abrasion resistance is evident when you grind it, as you now know.


----------



## Tombstone

Brento said:


> I need to go back through this thread so i can find the examples and instructions.


page 11 there is a new PDF


----------



## Tombstone

It took a few sessions tho the last 2 weeks, and quite a few re-readings, but I finally made it through this. Did missed the part 2 as it was info overload.  What a fantastic thread!
Are we still putting pic up as it gets pass round?

 Mikey you have don a really good thing on here.

If there any Aust on here I still lokking for some thing better then buy the HSS tools from https://www.ebay.com/itm/50pcs-3-8-...e=STRK:MEBIDX:IT&_trksid=p2060353.m2749.l2649

But the sipping is 2x the price so its a no go for me.


----------



## mikey

Tombstone said:


> It took a few sessions tho the last 2 weeks, and quite a few re-readings, but I finally made it through this. Did missed the part 2 as it was info overload.  What a fantastic thread!
> Are we still putting pic up as it gets pass round?
> 
> Mikey you have don a really good thing on here.
> 
> If there any Aust on here I still lokking for some thing better then buy the HSS tools from https://www.ebay.com/itm/50pcs-3-8-x-3-HSS-Square-tool-bits-for-69-00-HS-2BT-38-new/311079480439?ssPageName=STRK:MEBIDX:IT&_trksid=p2060353.m2749.l2649
> 
> But the sipping is 2x the price so its a no go for me.



Thanks for the kind words, Tombstone, and yeah, we really want to see your tools! I hope they work as well for you as they do for me, and that they help you enjoy this great hobby.


----------



## Tombstone

Have not seen any photos for awhile. who's that the HSS tolls right now?


----------



## Brento

Tombstone said:


> page 11 there is a new PDF


Ive got the pdf unless it was updated


----------



## Tombstone

Can you send it to me I must of missed it. It's  a quite of a read to this point. Should be getting Mike's HSS tools soon when there finish with the last guy or the next guy. I'm in Australia.


----------



## Vacuum

What a great thread. Has to be up to being close to #1. Absolutely fabulous information and instructions. Mikey is great and describing the process and is very modest in in his presentation. I would like to know what he has forgotten. To all the posters you also are a great asset. All are very willing to encourage the NOOB and seasoned participents who want to expand their skills without be negative. As far as I am concerned this it by far the best forum on the interweb. I feel honored to associated with you all. Thank you. Now off to try my hand with some tangtung bits.


----------



## Vacuum

Trendiwax may have been discontinued by the manufacturer. Can anyone confirm or lead me in the direction of what I am looking for to be able to search. I used to use a DoAll product for band saw blades but it was also discontinued.


----------



## DHarris

Brento - there is the latest MS word doc with all of Mikeys tutorial in it on page 22 - post #657


----------



## Tombstone

Find it thanks guys will get that one printed ASAP. There 38 pages now


----------



## mikey

Vacuum said:


> Trendiwax may have been discontinued by the manufacturer. Can anyone confirm or lead me in the direction of what I am looking for to be able to search. I used to use a DoAll product for band saw blades but it was also discontinued.



Hey Vac, a belated welcome to HM! Thank you for your kind words but to keep things in perspective, I learn best from my mistakes. If I seem to know something, it means I screwed up ... a LOT! 

All the stick waxes are about the same. Search Amazon for "stick wax lubricant" and pick the cheapest option. You don't need a lot; just a few seconds of application with the belt running will do ya'.

By the way, Tantung bits can be a challenge to grind. Some M2 is easier and will work for most stuff.


----------



## Aaron_W

Ok, I'm still digesting this. I've started to ask a question several times, but then thinking it through I find the answer is actually somewhere in what you have written, either specifically or readily implied.

I keep thinking if a sharper angle is less work for the machine, then why not more. Obviously there must be a point where to much is too much, and I keep coming back to an answer only to read through you posts again and see this.




mikey said:


> Guys, there is something about a 15° relief angle that just works. I don’t know why this is; it just works.



Considering how often I seem to see this angle in your tools, that explains a lot.


At least on our end it seems like the very simplified summary is shallower angles are easier on the tool (less need to sharpen) while the steeper angles are easier on the machine (cuts better, with less force).




One item that seems to have only been briefly touched on is tool size, larger being more rigid, smaller being cheaper and easier to grind. I'm not seeing anything to suggest the tool size has much effect beyond that. What works well on 1/4" will probably work even better on 3/8" or 1/2".

The trade off seem to be cost, and grinding effort, vs stiffness and tool durability. Does that pretty much sum up tool size?

Perhaps some minor fine tuning needed based on the tool flex, but a bigger tool doesn't seem to result in a larger, less agile contact point, it just has more material backing it up.


I've been using 1/4" tooling all this time and when I was playing with aluminium and brass that seemed fine. Steel seems to be more of an issue, so I've bought some 3/8" blanks to try out to see if the additional rigidity helps on these harder materials. Nothing too fancy just 12L14, and some hot and cold rolled.

I'm going to carve one of the 3/8" blanks into a square tool and see how that goes.


----------



## mikey

Aaron_W said:


> I keep thinking if a sharper angle is less work for the machine, then why not more. Obviously there must be a point where to much is too much, and I keep coming back to an answer only to read through you posts again and see this.
> 
> 
> 
> 
> Considering how often I seem to see this angle in your tools, that explains a lot.
> 
> 
> At least on our end it seems like the very simplified summary is shallower angles are easier on the tool (less need to sharpen) while the steeper angles are easier on the machine (cuts better, with less force).



Let me say that there is no magic number for any angle. What works for me may or may not work for you. I tested every single angle on each of my tools and found what I think is the optimal angle for a given material but to say those angles are correct is just plain hubris. The 15 degree angle thing is just something I've observed; it is not a rule or anything. Let me illustrate.

When I was trying to optimize my threading tool, I ground 10 separate 1/4" tool bits with relief angles from 8 to 17 degrees (zero rake) and cut 10 separate 1/4-20 threads in 12L14 steel. Under 10X magnification, I looked at edge wear and how clean each thread was cut; all subjective but it is what it is. I found that as the relief angle increased the threads got cleaner and cleaner until I hit 16 degrees. What seemed to happen is that I began developing edge wear and that showed up as more burrs, and 17 degrees was worse. 15 degrees cut clean threads with a nice finish and the edge held up really well. I have since cut threads in brass to semi-hardened steel with that 15 degree tool and have gotten really good results and no significant edge wear. I normally only give the top of the tool a few strokes with a diamond stone from time to time and haven't had to re-grind a tool for well over 10 years now. So, 15 degrees is not magic; just tested and found to work well for me on my lathes in my hands. 



Aaron_W said:


> One item that seems to have only been briefly touched on is tool size, larger being more rigid, smaller being cheaper and easier to grind. I'm not seeing anything to suggest the tool size has much effect beyond that. What works well on 1/4" will probably work even better on 3/8" or 1/2".
> 
> The trade off seem to be cost, and grinding effort, vs stiffness and tool durability. Does that pretty much sum up tool size?



As long as your tip geometry is good, tool size is not a major factor. This is especially true for softer materials. In harder stuff, like higher carbon and tool steels, you will probably see a better finish with the larger tool size. I don't know if this is a resonance thing but I suspect it is. I use 3/8" bits because they are stiffer and cut better for me vs 1/4" tooling, and I tested them pretty exhaustively. I can also use the same tools on my Sherline or my 11" lathe. It takes me 2 minutes to grind a 1/4" tool and under 4 minutes for a 3/8" tool. It takes 8 minutes for a 1/2" tool but without any gain in performance so I don't use them.

I suggest you grind identical tools in 1/4" and 3/8" blanks and see which works better for you. Its the only way to tell, and once you know it then you know it and nobody can tell you different. The same applies to your tool geometry. Test it yourself so that it works well for you and ignore what anyone else tells you to do, including me. 

I am always leery about sharing tool angles. This is why my initial post in this thread said that these are my tools used on my lathe; it is right for me but it may not be right for you. This whole thing isn't about duplicating my tools. It is about learning to design and grind tools that work for you. I hope that is clear to everyone because the last thing I want anyone to think is that I'm some tool grinding guru or that my way is the only way; I'm just one of the guys.


----------



## ttabbal

You know you're the lord of the angles... 

I've tried a few changes, though not under a microscope. I find 15 works well for most things so far, of course, most things amounts to all of three things that I happen to have in the shop, so it's far from exhaustive. And it plays to my lazy streak, I don't have to adjust the table angle!


----------



## ttabbal

Here's my latest tools. For threading close to a shoulder. I cut a thread that fit perfectly into a tapped hole. And, no, I didn't grind the first one backwards. I would never do that......


----------



## mikey

Travis, you made me smile! You made a tool your own way and it worked - awesome!!! This is the kind of thing that I love to see.


----------



## ttabbal

mikey said:


> Travis, you made me smile! You made a tool your own way and it worked - awesome!!! This is the kind of thing that I love to see.



I'm glad I posted them then! I like seeing other people's tools, so I thought I'd share. Having the parts thread together perfectly was very satisfying. 

What other types would work for that job? 

Tip for change gear users... Always double check the pitch on scrap. I use some random PVC pipe pieces I have around. I managed to flip a gear set and had about 5TPI. I was aiming for 14.  I had to guess on what I ended up with, it wasn't on the machines' chart and my pitch gauges stop at 8.


----------



## Z2V

For you guys in Australia we now have a set of Mikey’s tool models there for you. Send me a PM if you would like to get on the list.


----------



## ACHiPo

Success (I think?) grinding a turning (square) tool.  I'm sure it would be easier with the models on hand, but wanted to try it just based on Mike's pictures and descriptions.  I think I'm close (it seemed to work very well in brass, just ok on 303 stainless).   Critiques appreciated.


----------



## mikey

Hey Evan,
It looks like you got the relief angles right and your tool shape is fine. However, the rake angles are problematic. I can see side rake but the back rake is slightly lower at the tip, which gives you a negative rake. The intersection of the side cutting edge and the top of the tool is also irregular so the tool may not cut well.

This is all easy to fix. Draw a line on your tool rest at about 15 degree from the horizontal, up near the belt. Lay your tool on the rest with the side cutting edge facing up and align the shank of the tool with the inked line on the tool rest. Keep the back of the tool flat on the tool rest and push it into the belt with your push block. Do not let the angle of the tool bit deviate when doing this. Let the belt cut until the grind reaches the tip of the tool. This will give you both a 15 degree side and back rake. 

Please give this a try and post up a pic. The rake angles are the trickiest for folks to grind but once you figure out how to hold the blank steady, this will be a piece of cake for you. Don't worry, you'll get it and I'll stay with you until you do.


----------



## ACHiPo

Mike,
One question I had was whether the top (back?) rake should be ground with the table set at 15º or 0º?  I ground it at 15º.  I did draw a 15º line on my table, but I am having tracking issues with my belt--it kept scooting as I put lateral force from the angled blank (which is why the back rake is "stepped").  I may be better off doing this step on the bench grinder until I figure out what I need to do to get the belt tracking rock-solid on my 1x42.

Will give it another shot next weekend.

Evan


----------



## mikey

ACHiPo said:


> Mike,
> One question I had was whether the top (back?) rake should be ground with the table set at 15º or 0º?  I ground it at 15º.  I did draw a 15º line on my table, but I am having tracking issues with my belt--it kept scooting as I put lateral force from the angled blank (which is why the back rake is "stepped").  I may be better off doing this step on the bench grinder until I figure out what I need to do to get the belt tracking rock-solid on my 1x42.
> 
> Will give it another shot next weekend.
> 
> Evan



Another complicating factor might be that platen. It attaches only on the bottom so rigidity is compromised; as you apply force into the belt, the platen moves backwards. You might look for ways to stiffen the platen, like welding side plates to it or perhaps a gusset of some kind behind it. Regardless, the platen has to be solid or your grinds will suffer.

The other thing you can do is find a stronger tracking spring to help keep the belt from moving.

I also found that ceramic belts cut much better than aluminum oxide belts. They require less pressure to cut well so you might want to try them.

Finally, try using M2 HSS instead of cobalt. Cobalt isn't hard to grind but it does require more pressure to cut and that might cause your belt to move. A ceramic belt plus M2 steel will give you a better chance at a decent grind.


----------



## Aaron_W

I've had more time with the square tool I ground. Initially I just took a stone to the tip to just slightly blunt it to create the nose radius. 

I've since sat down and spent a little more time fine tuning the radius with a stone, and have found it makes quite a difference. 

It was working well enough before, but it now turns out a better finish and peels off long (1/2" - 2") strips of brass and aluminum instead of little flakes. Really kind of neat to watch and easier to clean up. Not long enough to get in the way.


----------



## mikey

Yeah, it makes a difference. I spend whatever time it takes to smooth the radius so that it transitions to both side and end evenly. The nose radius is involved in every cut you take with a turning tool. Even a facing cut involves the very end of the nose radius. It pays to do this part of the honing job well. Make sure to make a light pass or two on the top of the tool after you finish honing the nose radius to remove any burrs that may have arisen.


----------



## shorton

Being past time to pass my models on, I forced myself to take time to grind the primary today.  With the excellent directions on post #104 I had no trouble.  My belt grit may have been a little light as it took a few minutes, especially on that first big cut.  But I was able to reproduce the shape, no problem, first try.  I tried touching the radius with the belt and think I made it too big.  Hard to see 1/32 at my age LOL.  A stone in order for that step.  I piddled with it taking some huge cuts in 6061 effortlessly.  Got a little galling on my tip but I had no lubricant which was probably part of the reason.  And no honing.  Excited to be able to do this.  Thank you.

Photos, models vs mine after playing around and I redid some edges a couple of times to sharpen the radius I made a hair big and ugly.


----------



## shorton

When using the tool, I'm fuzzy on what the tool angle is supposed to be relative to the workpiece.  Not shank/square I gather.


----------



## ttabbal

The radius is tough to do on the belt properly, for me anyway. I found the coarse diamond card works well with a bit of pressure it only takes a few passes. Then just blend it in.


----------



## shorton

Thanks, can you point me to and example of exactly what I need to order?


----------



## ttabbal

shorton said:


> When using the tool, I'm fuzzy on what the tool angle is supposed to be relative to the workpiece.  Not shank/square I gather.



Start with it perpendicular to the work and ensure that the tip is on center. Angling a bit toward the headstock or tailstock changes how the tool cuts. A few degrees toward the headstock roughs a bit better, toward the tailstock gives better finish. A lot depends on your specific tool, lathe, and workpiece, so it's good to experiment and learn your setup on some scrap when possible.


----------



## ttabbal

shorton said:


> Thanks, can you point me to and example of exactly what I need to order?



I use these and have had good results. 

https://www.amazon.com/dp/B00006IIO3/ref=cm_sw_r_sms_awdo_t1_vK55Ab4AGC6W4


----------



## ACHiPo

mikey said:


> Another complicating factor might be that platen. It attaches only on the bottom so rigidity is compromised; as you apply force into the belt, the platen moves backwards. You might look for ways to stiffen the platen, like welding side plates to it or perhaps a gusset of some kind behind it. Regardless, the platen has to be solid or your grinds will suffer.
> 
> The other thing you can do is find a stronger tracking spring to help keep the belt from moving.
> 
> I also found that ceramic belts cut much better than aluminum oxide belts. They require less pressure to cut well so you might want to try them.
> 
> Finally, try using M2 HSS instead of cobalt. Cobalt isn't hard to grind but it does require more pressure to cut and that might cause your belt to move. A ceramic belt plus M2 steel will give you a better chance at a decent grind.


Mike,
Great input as usual.  I am using ceramic belts, and even stepped up to an 80 grit for this task, even though 120 grit is amazingly aggressive.

I think I need to figure out a way to strengthen the arm of the grinder.  I'll just get the belt tracking dialed in, then if I put any sideways force on the arm the belt will hop to the side.  The spring seems plenty strong.

I suspect you're right about the platen.  Until I get a chance to dial in the belt grinder, maybe my best bet is the 8" bench grinder with 36 and 80 grit wheels.  I'll also see if I can't find some plain HSS.


----------



## Aukai

I have a 2 x 48 belt grinder. What I did to reinforce the platen was to cut down a piece of box tubing that my platen fit well, then welded them together, and added/epoxied the Pyrex glass to it.


----------



## mikey

shorton said:


> Being past time to pass my models on, I forced myself to take time to grind the primary today.  With the excellent directions on post #104 I had no trouble.  My belt grit may have been a little light as it took a few minutes, especially on that first big cut.  But I was able to reproduce the shape, no problem, first try.  I tried touching the radius with the belt and think I made it too big.  Hard to see 1/32 at my age LOL.  A stone in order for that step.  I piddled with it taking some huge cuts in 6061 effortlessly.  Got a little galling on my tip but I had no lubricant which was probably part of the reason.  And no honing.  Excited to be able to do this.  Thank you.
> 
> Photos, models vs mine after playing around and I redid some edges a couple of times to sharpen the radius I made a hair big and ugly.



Looks really good, shorton! You got all the angles right - looks just like the model. It amazes me that you guys can do this right off the bat.

Travis has given you the dope on lead angles using far fewer words than I did in post 107.

I also agree with him re the diamond stones for honing - I use the same ones.


----------



## mikey

ACHiPo said:


> Mike,
> Great input as usual.  I am using ceramic belts, and even stepped up to an 80 grit for this task, even though 120 grit is amazingly aggressive.
> 
> I think I need to figure out a way to strengthen the arm of the grinder.  I'll just get the belt tracking dialed in, then if I put any sideways force on the arm the belt will hop to the side.  The spring seems plenty strong.
> 
> I suspect you're right about the platen.  Until I get a chance to dial in the belt grinder, maybe my best bet is the 8" bench grinder with 36 and 80 grit wheels.  I'll also see if I can't find some plain HSS.



Yeah, if the chassis of the grinder is moving under pressure then you're gonna' have issues. You have to find some way to stiffen things up. 

Aukai's platen mod is a really, really good one!


----------



## mikey

Aukai said:


> I have a 2 x 48 belt grinder. What I did to reinforce the platen was to cut down a piece of box tubing that my platen fit well, then welded them together, and added/epoxied the Pyrex glass to it.



This sucker ain't moving, that's for sure!


----------



## Aukai

I think it did add some stiffness to it.


----------



## Bob Korves

These hones also work well:
https://www.amazon.com/gp/offer-lis...ywords=ez+lap+diamond+sharpener&condition=new
The file shape is easy to hold and work around the tip of a tool.  They are definitely expendable, so do not last forever.  It helps if you do not push hard with them, a lighter touch works just as well, let the diamonds do the work.


----------



## shorton

Ok, emboldened with how easy this basic square tool was for me, now I need a boring tool.  Is there somewhere good to explain that shape?  I have 2 cases:
1. I gather one can do it with a normal piece of square stock like I have (3/8") but the bore would be limited by the tip size obviously. 
2. I've got a boring bar that has a holder/clamp for a teeny piece of tool material.  I have no idea how to point that piece.
Be great if there were some instructions as good as post#104.  Or similar.


----------



## mikey

shorton said:


> 1. I gather one can do it with a normal piece of square stock like I have (3/8") but the bore would be limited by the tip size obviously.



Boring bars can be ground but it involves taking a lot of material off. To be honest, it is simpler to buy one. Note, too, that a steel bar can only go to a depth that is about 4 times the OD of the smallest diameter of the shank. For example, if you had a 3/8" square bit and necked it down to fit into a 1/4" hole, the tapered part of the bar would be about 3/16" OD, so the depth of the bore would be limited to about 3/4" deep. A similar carbide bar from Micro 100 could go almost 2" deep. I no longer grind boring bars. Instead, I use solid carbide bars from Micro 100 for smaller bores and inserted carbide bars for deeper bores.



shorton said:


> 2. I've got a boring bar that has a holder/clamp for a teeny piece of tool material.  I have no idea how to point that piece.
> Be great if there were some instructions as good as post#104.  Or similar.



This might help: http://homews.co.uk/page140.html


----------



## shorton

Thanks.  For some bigger bores I bought a insert bar that holds some inserts I got that I understood were for alu.  It tends to make a chip ball/nest when boring something I do that's pretty big ID (6").  

As for carbide tooling... almost everything I do is aluminum and my understanding was that carbide required much higher speeds to work well, and my little Southbend 9 won't go very fast.

For smaller stuff that I can' tdo with the large insert bar, I have this holder I mentioned (picture).  Size wise it's been suitable for some bores I wanted to do, but I don't know how to grind it's point.  From the education I've gotten here on the square tool I could probably make a stab at it.  Being a noob though I dont' know which direction to cut when boring.  I've been cutting toward the head.

Given the photo, any suggestions on the tip geometry for that piece of HSS?


----------



## mikey

Sorry but I don't know much about that type of bar. Looks like an Everede bar. They are still in business and it might be worth a shot to send them an email. I know they make bars with different tip angles and the bits are ground to that geometry.

You can also start a thread on the forum about this type of bar. I know some guys use them.

Boring is a huge discussion. Carbide inserts can be used quite effectively for boring but the geometry of the bar and insert is well beyond this thread.


----------



## ACHiPo

Got my models duplicated.  My platen is too wide on my belt grinder, so I had to use my bench grinder for my back rake. The HW store only had 3” key stock, so my models are the short ones
.
	

		
			
		

		
	











Critiques?


----------



## mikey

The rake angles look much better evan. As you practice, focus on keeping the tool shank aligned with the inked line on the tool rest and the back of the tool flat on the tool rest. 

For example, in the third picture, the short tool second from the bottom: you lost your alignment with that inked line and also ground too much of the tip down. This resulted in the loss of most of the back rake and the tip of the tool no longer aligns with the level of the shank. Contrast that to the first tool; the height of the tip is even with the shank (good) and the back rake is retained. 

The shape of your tools is fine.

Grinding the rake angles takes practice but you're getting it quickly. Good job!


----------



## ACHiPo

Mike,
Thanks.  I got the belt tracking better now, but I need to mill down the platen on my belt grinder--it's about 0.1" wider than the belt.  Once I can use the edge of the belt I can do much better on the back rake.  My bench grinder has issues as well--I can't find my diamond dresser and the wheel needs to be trued up.

Anyway, having the physical models helped tremendously.  Great idea!

Evan


----------



## mikey

ACHiPo said:


> Mike,
> Thanks.  I got the belt tracking better now, but I need to mill down the platen on my belt grinder--it's about 0.1" wider than the belt.  Once I can use the edge of the belt I can do much better on the back rake.  My bench grinder has issues as well--I can't find my diamond dresser and the wheel needs to be trued up.
> 
> Anyway, having the physical models helped tremendously.  Great idea!
> 
> Evan



The platen is critical in my view. It has to be flat and solid and you have to be able to track the belt beyond the right edge of it by about 1/16" when grinding the rake angles on a RH tool. I would strongly recommend you brace the platen in the back so it cannot flex at all and put a Pyroceram liner on it; this will allow you to grind accurately and it will last for many years. 

Much of tool grinding is in the machine. While the person is important, the tool rest and platen have a significant impact on how well your tools turn out. I have a feeling that if these two things are addressed on your grinder, the results will amaze you. Please keep us posted, Evan, because I'm truly interested in seeing you do well.


----------



## ACHiPo

I milled 0.050" off the right side of the platen.  Definitely a step in the right direction.  The belt is just proud of the platen, maybe 0.010", so I need to give it a little more, but will wait until I brace it and add the pyroceram.

I dove in an tried my hand a grinding a stainless steel tool.  Without pictures, I'm hoping I interpreted the guidance correctly.  Here are pics of the tool and the tool in operation.  The chips varied between never-ending strings, nice 1" curls, and short (1/4" curls).  The tool seemed to cut decently, and I could take 0.050" deep cut with the gear box in its lowest gear without lugging down the machine.  I did get a lot of (presumably sulfur?) smoke.







The stainless part I made is on the right.  Finish is not great, but no chatter to speak of.  I machined the 1/2" section with my stainless tool.  I fixed the geometry of my square tool and cleaned up the base with it.  The square tool worked much better with more back rake, but the stainless tool worked better yet.  The 28º side rake is pretty acute and doesn't leave much meat at the tip.  I stopped 3 times and honed the tool.


----------



## mikey

Light cuts with any tool in stainless will string; this has to do with the ductility of the material. Like aluminum, stainless will string with light cuts. You can improve the finish with a nose radius, Evan. You tool as shown has little to none ... maybe my eyes can't see it. You can also improve the finish by angling the tool a little bit more toward the tailstock. Also, if you take light cuts, you can improve the finish by angling the tip of the tool toward the chuck and cut with the nose and end cutting edge; it will string but the finish will be better because the end cutting edge will shear.

Yeah, you're right; a stainless tool has a lot of side rake but that is a good thing. It gets the heat out of the cut faster so you have less potential to work harden the work piece. You still have to use the tool correctly, which means you cannot dwell or pause in the cut. 

You might also give Anchorlube a try. I've been using it for stainless steel and it seems to work quite well for that. Considering it is a soap-based product, this was surprising to me. I need to compare it to sulfur-based cutting fluid one of these days to see which works better. If the Anchorlube wins, then I'll use it for threading and knurling and see how that works. I have found that I get less smoke, cleaner finishes and the chips coil more with Anchorlube so that's a plus. It still strings with light cuts but when I take deeper cuts or if I increase the feed rate then I get chips but this is not due to the lubricant; it is due to the geometry of the tool.


----------



## ACHiPo

Mike,
I realized last night the side rake of 28º was taken from the wrong reference, making my side rake effectively 62º.  This would explain the fragility of the edge.  Man it's been a long time since geometry and trig!







I did use AnchorLube on the last pass of 0.010".

I don't have a feeling for honing a 1/16" radius on the end of the tool.  To get a radius I rolled the edge on my fine diamond stone 3-4 times, then honed the back rake.  I can certainly increase it.  I think I saw that someone honed a 1/32" flat on the edge, then smoothed it.  That may be a better way to proceed.


----------



## rolleikin

Hi Everyone,

I know that I am coming late to this party, but we may want to add to this wish list cutting tools for a shaper. The relief angles on shapers are shallower than on a lathe. Unfortunately, I no longer have my copy of Leo St. Claire's book on cutting tools, or I would have provided some references. 

Thank you for taking on this project.

Just my 2 cents.
Andrei


----------



## ttabbal

ACHiPo said:


> I realized last night the side rake of 28º was taken from the wrong reference, making my side rake effectively 62º.  This would explain the fragility of the edge.  Man it's been a long time since geometry and trig!



That's pretty easy to do, don't feel too bad.  



ACHiPo said:


> I don't have a feeling for honing a 1/16" radius on the end of the tool.  To get a radius I rolled the edge on my fine diamond stone 3-4 times, then honed the back rake.  I can certainly increase it.  I think I saw that someone honed a 1/32" flat on the edge, then smoothed it.  That may be a better way to proceed.



The best way I found was to use the coarse diamond card and press a bit harder than I do for normal honing. I do a flat a little less than I'm aiming for, then use a rolling motion to round it out and blend with the sides. Once it's there, I don't have to do much to it later when honing the tools. I tried using the belt grinder, but you're trying to remove such a small amount that it's tricky to get it even, even with the finer belts.


----------



## ACHiPo

ttabbal said:


> That's pretty easy to do, don't feel too bad.
> 
> The best way I found was to use the coarse diamond card and press a bit harder than I do for normal honing. I do a flat a little less than I'm aiming for, then use a rolling motion to round it out and blend with the sides. Once it's there, I don't have to do much to it later when honing the tools. I tried using the belt grinder, but you're trying to remove such a small amount that it's tricky to get it even, even with the finer belts.


 I don't feel bad--I'm learning lots, and pretty quickly.  I've gone from not having a clue what I didn't know, to understanding a little more about what I don't know.  Progress!

I suspect your technique on the radius creation is what I remembered.  My radii are definitely smaller than would be created by smoothing a flat, and likely way too small.


----------



## mikey

ttabbal said:


> The best way I found was to use the coarse diamond card and press a bit harder than I do for normal honing. I do a flat a little less than I'm aiming for, then use a rolling motion to round it out and blend with the sides. Once it's there, I don't have to do much to it later when honing the tools. I tried using the belt grinder, but you're trying to remove such a small amount that it's tricky to get it even, even with the finer belts.



This is how I do it, too, Evan. The nose radius is an important feature, to me anyway, so I take the time to do it well. 

As for the angle thing, don't worry. It takes some time to wrap your head around these stupid angles. I swear that if you have seen all the mistakes I made you would wonder how I ever got it straight. You're doing fine. Just keep working at it and you'll sort it out.


----------



## mikey

rolleikin said:


> Hi Everyone,
> 
> I know that I am coming late to this party, but we may want to add to this wish list cutting tools for a shaper. The relief angles on shapers are shallower than on a lathe. Unfortunately, I no longer have my copy of Leo St. Claire's book on cutting tools, or I would have provided some references.
> 
> Thank you for taking on this project.
> 
> Just my 2 cents.
> Andrei



Hi Andrei, and welcome to HM.

I don't own a shaper and know very little about shaper tools. However, I am familiar with how it cuts. Not too long ago, I was contacted by one of our members, UlmaDoc, who has a little Aamco 7" shaper. He wanted a tool that would hog cuts in aluminum while leaving a good finish. He was using a traditionally shaped tool that was giving him 0.050" deep cuts but he wanted to go deeper. Our collaboration eventually resulted in a tool that is shaped very much like a lathe tool and it was able to take 0.214" deep cuts with a good finish. He did a video showing how this tool worked:






We also did a tool for steel but I don't know how well that one worked (well, I sort of do; it seems to have worked well but he didn't try really deep cuts). The gist of it was that we tried an oblique cutting tool instead of the traditional orthogonal cutting tool and it worked much better for stock reduction. Of course, when cutting features like dovetails or slots, the tool would need to be shaped for the job but the geometry could likely be altered to improve performance. His little 7" Aamco shaper only has 1/4HP so we needed to get cutting forces as low as possible. Again, I'm no shaper tool expert by any means but a cutting tool is a cutting tool and at least to the extent possible, it seems to have worked


----------



## Z2V

I have a set of model tools available if anyone is interested. PM me if you would like to see them.


----------



## TerryH

mikey said:


> I swear that if I could get you guys in my grubby little hands for one hour, I could teach you all I know about this tool grinding stuff.




Given your location, I think we should reconvene this discussion to your house ASAP.  I'll bring my sander. Should be an interesting conversation piece as a carry on. lol...


----------



## ttabbal

TerryH said:


> Given your location, I think we should reconvene this discussion to your house ASAP.  I'll bring my sander. Should be an interesting conversation piece as a carry on. lol...



I've threatened to invade him a couple of times. He calls my bluff, but I do have family on the islands....


----------



## mikey

You guys are welcome if you're ever on Oahu. I'll be sort of ashamed to show you my little belt sander after the new ones you guys made up but my hands move on their own after 30 years of tool grinding - bet there's still something I could show you!


----------



## Camnefdt

Finally made it to the end! 

What a read!! And big ups to Mikey and jeff for everything done so far, incredible information available at our fingertips as long as we are willing to put in the effort and attempt it ourselves! 

So Mikey has already seen my first ever attempt at grinding a tool which wnded up a disaster after an attempted touch up haha.

But this is my second attempt ever at grinding up a tool. Was working with an old bench grinder that desperately needs to be dressed and a tool rest that was not able to be adjusted so everything was done free hand with a protractor in one hand for referance!







This is before being honed.


----------



## ACHiPo

Nice job!


----------



## mikey

Under the circumstances, not sure I could have done it any better. Good job!


----------



## thomas s

Yes good job.


----------



## Z2V

Looks really good considering what you had to work with.


----------



## Esmith41

Hello and a big thanks to Mikey and Jeff for starting the pattern sharing. I just got my lathe up and running a few weeks ago and tried sharpening my own bits based on what I thought I knew. My surface finish was terrible and it sounded like I was grinding the chips off if I took more than .003. So I requested a set of bits from Jeff and just got my set of patterns done tonight. I hope to grind a few HSS bits tomorrow night after work. I don’t have a sander but I used my slow speed grinder. Here are my results. My bits are on the right side of each pattern. They are all the same three bits just rotated to show the different profiles.
	

		
			
		

		
	





	

		
			
		

		
	
 Now I just need to learn how to use them.Thanks again guys!!
Eric


----------



## Headrc

Hi guys ....

So I have read through about 30% of the posts here and got in line to have the samples sent to me.  One thing I have not found ...so far ...what about cutoff/parting tools?  I have not found anything on sharpening them here ....or for that matter on Youtube channels like Tubalcain's.  Thanks, Richard


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## mikey

Eric, it looks like you nailed all the angles - good job! When you're ready, do the same thing in HSS and let us know how they work for you. Pretty sure they'll beat 0.003"! If you post pics of the tools themselves then we can critique them for you and help you get them working well for you. Congrats!


----------



## mikey

Headrc said:


> One thing I have not found ...so far ...what about cutoff/parting tools?  I have not found anything on sharpening them here ....



What kind of parting tool are you referring to, Richard? If it is the P or T-type, then it just has a relief angle below the tip. Standard angle is 5 to 10 degrees; I use 7 degrees. The easiest way to do that is to use a protractor and ink a line at 7 degrees as shown below:




When viewed from the top of the tool, the face should be straight across the front. The easiest way to grind it is to place the blade into the tool holder with just enough blade extension to allow you to grind without hitting the tool holder. Hold onto the tool holder and grind to the line.

If you're talking about grinding a tool from a square bit, I don't do this anymore. They are cumbersome to grind and don't work anywhere near as well as a P-type blade.


----------



## Headrc

Being a total newbie I probably stepped in it.  I really don't know what type of parting tool I was asking about ....just the knowledge that at some point you are going to want to cut or part something you have turned.  So is it that we are to just purchase a parting tool ...and then keep it sharp from your detail above?  And not try to create one from scratch?  Sorry for being so dumb here ...I am moving as fast as my little mind can.


----------



## mikey

Absolutely not dumb; it is, in fact, a valid question. Parting is something we all need to do and it should be a simple, routine job. You turn the part, determine where you want to cut it off and then feed a parting blade into the work to separate it from the stock that is held in the chuck. Sounds simple enough and it really is that simple when everything goes right. The problem is that for many guys, parting is a major PITA because of chatter and that chatter has many potential causes, only one of which is the tool itself. I'm not going to go into setting the lathe up for parting unless there is interest by the guys in this thread.

I will suggest you not attempt to grind a parting tool from scratch. A parting tool must have relief angles in front and on both sides and the side relief angles need to be the same or the tool will steer. It is much easier to just buy a tool and get on with your life. I highly recommend a P-type tool on your small lathe. You can also use carbide tools if you choose but a thin P-type blade will cut with lower cutting forces and is easier to use. P-type blades come in various widths, from 0.04" thick on up to 1/8". 




Most of these blades are 1/2" tall. There are T-type blades as well and those are larger. 

So, how do you choose one? The larger the work diameter, the larger the blade is supposed to be. This is not a hard and fast rule. For example, a P1-N is typically used for work up to about 3/4" OD. If the work is larger than that then you would step up to P1, which works up to about 1-1/4", and so on. This is when the blade is used with the cutting edge on top. However, if the tool is mounted upside down at the rear of the work then a thin blade can part much larger work pieces. I use a rear mounted parting tool on my Sherline lathe and a P1-N blade only 0.04" thick can part work up to 2" in diameter at very high speeds. So, choosing a blade depends on how you mount it and how large the work is.

If I were you, I would buy a decent P1 blade from AR Warner. There are many cheaper blades but the one from AR Warner is ground well and will last you for many years if you take care of it. I would also look into mounting the tool upside down and run the lathe in reverse to part; this will save you mucho grief. You can either make a tool holder or buy one from Eccentric Engineering: https://www.eccentricengineering.com.au/index.php?option=com_content&view=article&id=31&Itemid=45. Another option is to make a rear mounted parting tool holder but your cross slide must have threaded holes or T-slots to allow you to mount it; this is the best way I've found to use a parting tool.

Hope this helps.


----------



## Headrc

Always soooo helpful ...thank you Mikey.  How about keeping these purchased tools sharp?  Any advice on that?

This begs another question ...what about boring bars?  Buy them pre-made as well?  If I am going to place an order and pay shipping I might as well pack the box and empty the wallet.  

Thanks,  Richard


----------



## mikey

A P-type blade stays sharp for some time if it is used properly. Grinding the primary 7 degree relief up front will leave a burr on top of the tool. Use an extra-fine diamond or bench stone and lay the top of the blade flat on the stone. Draw back lightly a few times and that will knock the burr off, leaving a razor-sharp edge on the tool.

Boring and boring bars is a HUGE discussion. It is probably the single most complicated lathe operation there is and the bars you choose and the way you use them matters. Here I am talking about boring a precise hole to tight tolerances with control, not a hole in a model canon. Everything, from the bar size and material the bar is made from to the geometry of the bar and insert to the nose radius of the tip matters. That kind of boring needs to come later. For now, I recommend you buy a cheap Chinese boring bar set like this one: https://www.amazon.com/dp/B0007TZZF...be84-d9bc618b97e4&ie=UTF8&qid=1532453152&sr=1

These cheap bars will let you get your feet wet for not much money. You will need to hone them with a diamond stone before use but they actually do work pretty well for such a cheap set. The linked set has a 1/2" shank and you may need an adapter for your QCTP: https://littlemachineshop.com/products/product_view.php?ProductID=1700

You can also buy cheap Chinese inserted carbide bars but the smallest of these are usually around 3/8" OD so they won't allow you to bore small holes. I would buy the cheap brazed carbide set I linked above. They will teach you a lot about boring.


----------



## Headrc

The tool models are on the way to me ...now for some reason locally I am only finding 3/8 low carbon steel keystock that is zinc plated ...have not found plain.  Will this matter in trying to learn to create these tools?


----------



## mikey

No, they grind the same. Not healthy to breath zinc particles, though, so use a fan and mask.


----------



## Headrc

No worries ...actually I use a shop vac with my grinders dust port ...and a mask.  Although I continue to look for just plain low carbon locally...


----------



## Headrc

Ok ...let's see if I am a halfway decent student here.  I got the models this past weekend and have spent time practicing and studying against the models.  It is a challenge to actually mimic those models with my grinder ...especially that rake angle but please give me your critique if I am on the right track and suggestions on how to improve.  Thanks Richard

Turning tool with the model:














Facing tool with the model:














Threading tool


----------



## Headrc

Trying to figure out the posting pictures here too ...so excuse the extra attachments


----------



## mikey

Not bad, Richard, especially considering you're a new guy using a bench grinder. I'd bet money those tools will cut pretty well as they are. 

The tool model you are calling a Turning tool is actually a knife tool used for facing. Both of your tools will work but the tool in the middle has better rake angles ground into it and I suspect it will cut better for you.

The tool you're calling a facing tool is actually a right hand turning tool or Square tool. Your tool on the far right will work better. The shape is nearly correct and the rake angles look pretty good. The center tool will also work but the rake angles are a bit shallow; it will cut but chip clearance may not be as good. 

The threading tool looks pretty good. Did you match it up to a fishtail gauge? If not then do so; it needs to be exactly 60 degrees and you need a tiny flat at the front like the model. 

Give the tools a try and see how they work for you. Don't forget to put a nose radius on your tools and ensure the radius follows the corner angle up front, from top to bottom. Hone the tools well and give them a try.

I highly recommend you reproduce the models in mild steel keystock and practice with keystock until you can duplicate the models very closely. Doing it with HSS can be challenging for new guys because it is much harder to grind. Keystock grinds easily and allows you to learn how to move your hands. 

Oh, and just so you know, you did waaay better than I did in the beginning. You're off to a great start so hang in there and let us know how your tools work.


----------



## Headrc

Thanks Mikey.  I guess I should get some regular key stock ...although again it seems locally all I can find is zinc coated ...and getting low carbon shipped to me was more expensive then the HSS blanks you recommended.  Which is why I just went with that.  On this ...do you think that it is possible to really duplicate your samples with a bench grinder?  Getting that top rake is really hard to do and I did my best to mimic it without grinding my hand.  

I don't even own a fishtail gauge yet ....so no the threading tool was not checked with that ...yet.  I will be getting one of course and check with that.  Although threading will not be on my hit list at this time due to the fact that my lathe does not have a quick change gear box or even back gears.  And in fact it may be another week or two before I even try regular turning with the other tools.  I am studying the whole process of using a lathe and do not want to even crank it up until I understand all of the nuances of it as a beginner.

I will take note on the actual uses of the tools and of course be putting a radius on them.  I did not do that because I wanted to make sure I was headed in the right direction.  

Sigh, looks like there is yet another piece of equipment on the agenda ....a smaller belt sander.  Just when I thought I was out ...they keep pulling me back in!  

You really are a giving and helpful resource ...as well as many others here.  Hopefully I can return the favor somehow.  Thanks, Richard


----------



## Esmith41

Headrc said:


> Thanks Mikey.  I guess I should get some regular key stock ...although again it seems locally all I can find is zinc coated ...and getting low carbon shipped to me was more expensive then the HSS blanks you recommended.  Which is why I just went with that.  On this ...do you think that it is possible to really duplicate your samples with a bench grinder?  Getting that top rake is really hard to do and I did my best to mimic it without grinding my hand.
> 
> I don't even own a fishtail gauge yet ....so no the threading tool was not checked with that ...yet.  I will be getting one of course and check with that.  Although threading will not be on my hit list at this time due to the fact that my lathe does not have a quick change gear box or even back gears.  And in fact it may be another week or two before I even try regular turning with the other tools.  I am studying the whole process of using a lathe and do not want to even crank it up until I understand all of the nuances of it as a beginner.
> 
> I will take note on the actual uses of the tools and of course be putting a radius on them.  I did not do that because I wanted to make sure I was headed in the right direction.
> 
> Sigh, looks like there is yet another piece of equipment on the agenda ....a smaller belt sander.  Just when I thought I was out ...they keep pulling me back in!
> 
> You really are a giving and helpful resource ...as well as many others here.  Hopefully I can return the favor somehow.  Thanks, Richard


Richard, you may want to dress your wheel and create defined edges on your wheel. I recently made a copy of the models and used a slow speed bench grinder with half way decent results. I am in the same boat as you as far as being a new turner. As long as we learn and progress each time we screw something up it’s a win in my book.


----------



## Headrc

Thanks Esmith ...the grinder was dressed when I used it.  But it seems I need more practice...and I agree with you.  I am also a guitarist (watching those hands!) and I know quite well the "practice makes perfect" phrase.


----------



## Headrc

Another question comes to mind now as a result of me becoming aware of the segment in the Southbend Lathe book  about tool bits and grinding .  Are the models we are using appropriate for quick change tool posts and their holders?  Or are they designed for the older style lamppost holders?  Also, I have this turret type holder on my lathe ...which you can see in the attached picture.  Are these models appropriate for it as well?


----------



## ttabbal

The models here are designed for a QCTP, not the lantern post. Your 2-way turret post should work fine with them though. 

If you build a 2x72, grinding tools is almost too easy. And it's useful for general shop grinding as well. Good work on those bits. I bet they will cut well, and only get better as you get practice.


----------



## mikey

I would use the zinc-coated keystock, Richard. Just use a mask and the dust won't be an issue (you should always use respiratory protection anyway). You need to understand that tool grinding is not an intuitive thing. It takes time for your brain to learn to move your hands to create unfamiliar shapes and nothing builds grinding skills faster than keystock. You are trying to learn control and that takes practice. Stick with keystock until you're comfortable that you can grind exactly what you intend and you'll be way ahead of the game. If it helps, I still use keystock when I'm grinding a new design. It helps me to see a tool in real time so I can examine the tool angles; I use keystock for this, not HSS.

Yup, I am absolutely sure you can duplicate the models with a bench grinder. The vast majority of hobby guys use bench grinders to grind their tools, not belt sanders. I can grind tools just as well on either type of machine; I just happen to prefer a belt sander. It isn't the grinder type; its the skill of the user that matters. Read through this thread and you'll see some fine examples of tools ground on a bench grinder. If I can, and they can, then you can.

Buy yourself a good protractor and a fishtail. Unlike other lathe tools, a threading tool requires precise angles so be fussy about it. 

I know that things may seem overwhelming at this point in your machining "career". There is so much to learn, tool and machines to buy and you don't even know what you don't know. Let me assure you that you are about to engage in the greatest period of growth you're likely to experience in your life. In 5 or 10 years, take a look back and see if it isn't true. Welcome to the hobby and welcome to HM!


----------



## tweinke

Hard to believe this thread is still going after all this time! My belt grinder is finialy in the sea trial stages and bugs are being worked out, I think it turned out nice. Too bad life has gotten in the way of my shop time, wife wants siding and windows on the house hopefully before winter she says. Gonna make me a busy man for a while. Will post a pic of the grinder soon. I'm still just using my bits ground to match the models and am happy we started this lesson!


----------



## mikey

Looking forward to seeing the grinder when you wife cuts you loose!

Yeah, this thread has been a surprise. Over 48K views and well over 700 posts. I guess we hit on a subject that has some value to the guys, eh?

By the way, thank you for all your support, Todd. You've been behind this effort from the very beginning and you were on my mind a lot when I wrote much of the material here.


----------



## Z2V

mikey said:


> Looking forward to seeing the grinder when you wife cuts you loose!
> 
> Yeah, this thread has been a surprise. Over 48K views and well over 700 posts. I guess we hit on a subject that has some value to the guys, eh?
> 
> By the way, thank you for all your support, Todd. You've been behind this effort from the very beginning and you were on my mind a lot when I wrote much of the material here.




Yeah Mike, you definitely hit on a good topic and did a great job explaining the grinding process. The tool models are still floating around with the members. 
Thanks for your effort putting the thread together.


----------



## mikey

Those models are out there because of your efforts, Jeff. The guys and I are grateful to you. 

We aren't done. I still have to find time to grind that Shear tool but right now I have other priorities. In the meantime, we can all work on helping the newer guys with their tools.


----------



## Aukai

Everyone's efforts have been very much appreciated.


----------



## 9t8z28

Mikey, I just made your knife tool based off of your superb directions from page 4 and 5.  I made a left hand knife tool yesterday and then a right hand knife tool today.  I made both of them from old stock of 3/8” Sterling Circle C tool bits.  
I was having trouble turning a grade 10.9.  I tried all of my insert tooling and couldnt get the diameter to size.  I also couldn’t get a nice finish on the face.  The insert would skip over some areas and cut in others.  I found this thread and went to work making the knife tool.  What an amazing tool!   I cannot thank you enough for sharing your knowledge.  I can now cut tenths so easily and I can face and get a mirror finish without having to use sandpaper to take out the tooling marks.   I think this will be my go to tool from now on.  
 Tomorrow I am going to make the square tool bit (right hand) but I am going to use a piece of 1/2” or 7/16” in either Rex 95, Cleveland Mo-Max ,Sterling Circle C, or Fagersta WKE 4.   I will be using it for a lot of tool steel and mild steel and some aluminum.   Any recommendations on which brand to use ?  
 Also, do you have any specs on grinding boring bars and flycutters?   I think I read somewhere that you use Carbide for flycutters and I do as well but I am not sure on the geometry.   Sorry if this has already been asked or if I should be posting another thread.   I tried searching for relative threads started by members but cant seem to figure out how to do it.  
Thanks again!  
Brandon T


----------



## ttabbal

I'm using a left hand square tool for a fly cutter with very good results.


----------



## Z2V

9t8z28
Welcome to the club. Mickey has done a great job teaching us new to the hobby how to grind cutting tools.
I use the Crucible Rex bits as well as the Cleveland but do not have the others you mentioned. What I have has worked well for me.
I don’t have much to offer on boring bars and fly cutters, others will chime in though.
Glad that you found Mickey’s thread


----------



## mikey

Thanks, Brandon. I'm glad to hear the knife tools works for you. It works pretty well for me, too.

The Rex 95 is a good tool bit; 5% cobalt but a fair amount of tungsten so it will handle the heat with harder materials like tool steels. A square tool will cut tool steels fairly well but a tool ground specifically for tool steels will work better. If you tell me what you're cutting maybe we can come up with something that will work better.

The square tool will also work on aluminum and is pretty good for mild steels. However, again, a tool ground for aluminum will work better than the square tool will. I know I gave the tool angles for an aluminum tool somewhere in this thread and it works well for me. The key difference between the square and aluminum tools is the back rake - this gets the cutting forces right up near the tip of the side cutting edge and it also really accelerates the chip flow, which keeps temperatures down. The square tool works pretty good in aluminum, too, so you might try both and see what you think.

As for grinding boring bars and flycutter bits, let me take them one at a time.

Boring tools can be ground to work very well. I can't even remember how many I've ground but what I've learned is that no matter how well the tool is ground or how hard the blank is, that old modulus of elasticity comes into play. A steel bar of any kind is still limited to a depth of 4 times its diameter. We can go deeper with care but consistency suffers. Contrast that to a carbide shanked bar of the same diameter that will go 8-10 times its diameter before running into deflection issues - big difference in depth, consistency and accuracy. For these reasons, I only use solid carbide inserted boring bars for most holes or Micro 100 solid carbide boring bars in small bores. I use inserted carbide bars because of their consistency; I can rely on them to take the cuts that I dial in all the way down the bore, whereas a HSS bar will not consistently do that.

Some guys like to grind HSS tool bits that fit sideways in the end of a steel bar. I've tried those but again, you are limited to the depth of the material the bar is made from. This doesn't work for me when I need to go deep so I don't bother with these anymore.

As for fly cutter bits, yeah, they work fine. However, they do wear faster because almost every cut is an interrupted cut so edge wear is a factor. I clearly remember fly cutting a longish piece of O-1 steel and having the finish change as I neared the end. My inserted carbide fly cutters don't do that if the insert is in good shape, which mine usually are. With that said, if you want to try a HSS tool then go with M2 steel; it handles interrupted cuts better than the cobalt or high tungsten tool bits will. A left hand tool like @ttabbal  said will work quite well in a fly cutter. The thing you want to avoid is a huge nose radius. I know that some guys like that sort of thing but it causes too much radial deflection so I don't use them.

Anyway, I'm glad you've joined us here. If you would like to share your tools or otherwise query, have at it and we'll all pitch in to help. The guys are now quite experienced and I've seen them step in to help others in other threads, which is awesome to see.

Edit: I have used Rex 95 and Cleveland Mo-Max and many others but am not familiar with the others you listed. Cleveland Mo-Max is M2, Mo-Max cobalt is 5% cobalt, and Super-Mo-Max is 8% cobalt; these are some of the finest tool bits made. Anything from Crucible/Rex is also very good. European tool bits tend to be really good, also. I know and have used ETM from Israel and feel they are as good as a Mo-Max bit.

I just looked at all my keeper bits, the ones I use the most, and they are made from either Cleveland, Crucible/Rex or ETM. One of my oldest knife tools is made from a Vasco Supreme T-15 bit - tough as hell.


----------



## Downunder Bob

An excellent and generous offer Mickey. I would offer to help, but postage from here in downunder is horrific. I might suggest that you explain that british threads are 55 deg and widely used in british commonwealth countries particularly Australia and New Zealand. The threading tool is exactly the same as you would use for 60 deg tool just the included angle is 55 deg. Although we have changed to metric there is still a lot of old equipment around that uses 55 deg threads

I believe there are a few members on this forum who are proud owners of Hercus lathes and mills. They were, for a long time, made in my home town Adelaide South Australia, they will all have imperial 55 deg. threads.

You might also include  a parting off tool as this an area where many people have problems, although parting off is a whole subject in itself and grinding the tool is the least of the problems.


----------



## mikey

Downunder Bob said:


> An excellent and generous offer Mickey. I would offer to help, but postage from here in downunder is horrific. I might suggest that you explain that british threads are 55 deg and widely used in british commonwealth countries particularly Australia and New Zealand. The threading tool is exactly the same as you would use for 60 deg tool just the included angle is 55 deg. Although we have changed to metric there is still a lot of old equipment around that uses 55 deg threads
> 
> I believe there are a few members on this forum who are proud owners of Hercus lathes and mills. They were, for a long time, made in my home town Adelaide South Australia, they will all have imperial 55 deg. threads.
> 
> You might also include  a parting off tool as this an area where many people have problems, although parting off is a whole subject in itself and grinding the tool is the least of the problems.



Thanks, Bob. You are referring to the British Standard Whitworth (BSW) thread, which is distinguished from the more modern threadform by having a 55 degree angle instead of 60 and a rounded profile at the root and crest of the thread. They are otherwise similar. BSW is commonly found on older equipment, for both fasteners and leadscrews. In fact, my Emco lathe uses a BSW threaded cross slide leadscrew; it is far more common to see this thread in countries outside the US. With that said, the BSW thread is not commonly used even in Europe anymore; the 60 degree metric thread is more common.

To grind a BSW threading tool, the process is exactly the same except you need a 55 degree fishtail and a rounded nose instead of a flat. They are used the same way as a 60 degree tool.

Parting tools are a lot of work to grind. I've made some in the past and they worked fine but in my opinion they are not worth the time and effort. A P or T-type blade is so much better, is fairly cheap and easy to find, are easily sharpened for the life of the blade and is my blade of preference. I also have inserted carbide parting tools but they tend to be on the thick side and I rarely use them. I'm sure others have the opposite opinion, which is fine.

I think that if you have a surface grinder and can grind the angled sides of a parting tool accurately then it might be worth the effort. I don't own one so ...


----------



## 9t8z28

Thanks for the reply and also for your dedication to helping every single person here.  I sincerely appreciate you sharing your knowledge with us.  You are truly a huge benefit to our community and we are very lucky to have someone so dedicated to helping others. 
I was gonna make a right hand square tool today but instead I got sidetracked and started on my second homemade slitting saw arbor.  I made the first arbor for slitting saws with a 1/4” mounting diameter using the 10.9 bolt that I mentioned in my previous post and now today I started on making a larger arbor for my saws with a 5/8” mounting diameter.  I am using a piece of 7/8” CRS and I just started turning down the shaft diameter to 5/8”.  (Yes I know I should have started with smaller round stock but its what I got and I dont mind making lots of chips, besides its good practice  ).  I have only taken about .030” off the 7/8” CRS so far using the knife tool.  I have been taking very light cuts ranging from a few tenths to .002”.  I tried turning the tool bit towards the chuck, parallel to the chuck and towards the tailstock and have not been able to get a decent finish although I will admit that I can take skim cuts on the diameter and take off as little as a few tenths and the diameter in 3.5” only differs by .0003” which I have never ever been able to do with any tool.   I cant believe it can skim tenths like this!  Anyway, I tried all different speeds and feeds and it has made no difference.  I should have made the square tool instead of trying the knife tool as Its my understanding that this tool wasnt designed specifically for turning as much as it was designed for facing or turning into shoulders. I dont want to seem like I am going back on saying how wonderful the knife tool works because it works wonderful, just not for what I am trying to use it for.  It faces beautifully but I need to get a good finish on this CRS. 
Is there a single square tool that I can make that will turn CRS and 01/W1 or do I need to make one for CRS and one for tool steel?  I really dont mind making 2 tools if its gonna give me a the best chance at a good surface finish.  I really dont need any tools for roughing, I’ve got that covered with a huge selection of inserted and brazed carbide tools and a bunch of AXA QCTP holders.  I understand that less tool changes equals faster production but this is a hobby so no need to rush.  Should I make a square tool to your previously quoted specs ?  I dont really need any tools right now for turning aluminum, I just need a good finishing tool for 01, W1, some CRS and the typical mystery metal.  Sorry if I somehow said I needed a tool for aluminum.  I dont think I did but I am ok with turning aluminum. 

By the way, not sure if you need to know or if its relevant because I assume that the majority of the guys and girls using these specific tools tools are doing so because our hobby machines are lighter duty, but my lathe is a Sieg C4.  Its the slightly smaller cousin to the C6 or the 8X and 9X lathes.  Mine is a 8.5x20 lathe.  Its got a torquey 1HP variable speed drive and rpm’s run from 90 to 2,000.  I also did away with the compound and have a solid toolpost which really stiffened things up especially for boring.   Occasionally I put back on the compound for tapers and some threading although I would like to try threading with only the cross-slide.   The carriage gibs were also replaced with tapered brass gibs which helped with lifting and I’ve also got a fancy dancy cam lock carriage lock for facing.    Lastly the spindle bearings were retrofitted with tapered rollers and the lathe sits on a 3/4” sheet of steel spanning the entire length of the bed.  I tell you this because although its in a light duty hobby class lathe it has been tightened up some to give it more stability and rigidity and it can take a huge cut for what it is in comparison to a 7x Sieg lathe.  I have ran large engine lathes so I am familiar with their power and rigidity as well, not saying they are comparable as far as rigidity and power but just giving you an idea of what it is and how I am able to compare it. 

In reply to the boring bars, I dont really have the cash for carbide bars that use indexable carbide inserts right now.  I have a few steel indexable boring bars that use CCMT inserts but I want to be able to bore smaller holes.  My smallest indexable bar can only bore from I think around .4” and up.  I have a few long pieces of round and square HSS that I would like to grind into boring bars.  I cant seem to find grinding info on bars anywhere.  I also have a few HSS boring bars that I picked up second hand but they need to be freshened up and I dont know if the angles are even right or what they should be.  Lastly I do have a few boring bars that use small square stock at an angle or straight but I don’t know what geometry these should have as well.  Again I would be using a lot of tool steel and CRS and some mystery metal. 
Just curious, what kind of inserted flycutter tools do you use, meaning what insert do they take and is the insert neutral ? 

In reply to the flycutter tool, can I use a left hand square tool for the geometry when using brazed carbide tool bits or does the carbide require a totally different geometry?   Same material as well, 01, W1, CRS and the mystery metal. 

I will post pictures of my tools that I made to your specs tomorrow.   Lately it’s been hard getting the time to get on the forums and ask questions and help others but I do the best I can.   Unfortunately, Sometimes I do more reading and learning than I do posting! 



mikey said:


> Thanks, Brandon. I'm glad to hear the knife tools works for you. It works pretty well for me, too.
> 
> The Rex 95 is a good tool bit; 5% cobalt but a fair amount of tungsten so it will handle the heat with harder materials like tool steels. A square tool will cut tool steels fairly well but a tool ground specifically for tool steels will work better. If you tell me what you're cutting maybe we can come up with something that will work better.
> 
> The square tool will also work on aluminum and is pretty good for mild steels. However, again, a tool ground for aluminum will work better than the square tool will. I know I gave the tool angles for an aluminum tool somewhere in this thread and it works well for me. The key difference between the square and aluminum tools is the back rake - this gets the cutting forces right up near the tip of the side cutting edge and it also really accelerates the chip flow, which keeps temperatures down. The square tool works pretty good in aluminum, too, so you might try both and see what you think.
> 
> As for grinding boring bars and flycutter bits, let me take them one at a time.
> 
> Boring tools can be ground to work very well. I can't even remember how many I've ground but what I've learned is that no matter how well the tool is ground or how hard the blank is, that old modulus of elasticity comes into play. A steel bar of any kind is still limited to a depth of 4 times its diameter. We can go deeper with care but consistency suffers. Contrast that to a carbide shanked bar of the same diameter that will go 8-10 times its diameter before running into deflection issues - big difference in depth, consistency and accuracy. For these reasons, I only use solid carbide inserted boring bars for most holes or Micro 100 solid carbide boring bars in small bores. I use inserted carbide bars because of their consistency; I can rely on them to take the cuts that I dial in all the way down the bore, whereas a HSS bar will not consistently do that.
> 
> Some guys like to grind HSS tool bits that fit sideways in the end of a steel bar. I've tried those but again, you are limited to the depth of the material the bar is made from. This doesn't work for me when I need to go deep so I don't bother with these anymore.
> 
> As for fly cutter bits, yeah, they work fine. However, they do wear faster because almost every cut is an interrupted cut so edge wear is a factor. I clearly remember fly cutting a longish piece of O-1 steel and having the finish change as I neared the end. My inserted carbide fly cutters don't do that if the insert is in good shape, which mine usually are. With that said, if you want to try a HSS tool then go with M2 steel; it handles interrupted cuts better than the cobalt or high tungsten tool bits will. A left hand tool like @ttabbal  said will work quite well in a fly cutter. The thing you want to avoid is a huge nose radius. I know that some guys like that sort of thing but it causes too much radial deflection so I don't use them.
> 
> Anyway, I'm glad you've joined us here. If you would like to share your tools or otherwise query, have at it and we'll all pitch in to help. The guys are now quite experienced and I've seen them step in to help others in other threads, which is awesome to see.
> 
> Edit: I have used Rex 95 and Cleveland Mo-Max and many others but am not familiar with the others you listed. Cleveland Mo-Max is M2, Mo-Max cobalt is 5% cobalt, and Super-Mo-Max is 8% cobalt; these are some of the finest tool bits made. Anything from Crucible/Rex is also very good. European tool bits tend to be really good, also. I know and have used ETM from Israel and feel they are as good as a Mo-Max bit.
> 
> I just looked at all my keeper bits, the ones I use the most, and they are made from either Cleveland, Crucible/Rex or ETM. One of my oldest knife tools is made from a Vasco Supreme T-15 bit - tough as hell.


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## 9t8z28

Thanks ttabbal.  I thought it would but flycutters scare me a little.  Its not the flycutter whipping around that scares me, its the time spent wasted grinding a tool bit that leaves me wishing I had just used an endmill and been done with it!


ttabbal said:


> I'm using a left hand square tool for a fly cutter with very good results.


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## 9t8z28

Thanks Z2V.  I dont want to jack the thread but I think I saw a CTS-V in one of your photos earlier on in this thread?   I think it was around page 4 or 5 that I saw the photo.   I have almost read every page of this thread. I think I’m up to page 22.   I am trying to absorb every bit of information from everyone that has posted here !


Z2V said:


> 9t8z28
> Welcome to the club. Mickey has done a great job teaching us new to the hobby how to grind cutting tools.
> I use the Crucible Rex bits as well as the Cleveland but do not have the others you mentioned. What I have has worked well for me.
> I don’t have much to offer on boring bars and fly cutters, others will chime in though.
> Glad that you found Mickey’s thread


----------



## mikey

First, thank you for your kind words, Brandon. We ALL stand on the shoulders of the guys who went before us, who shared knowledge freely and helped us along the way. You, me and the other guys on the forum all try to help when we can. Together, we can keep the hobby and HM healthy and growing.

Okay, before we get too far, you're using CRS. I assume you mean cold finished rod but I'm not clear which steel it is. CRS is usually used to describe CR1018, 1045, 1141, 1144 and there is even CR12L14. Clearly, there is a difference so which one are you using? Most CRS has a higher carbon content and greater density due to the forging it undergoes. While not as hard as tool steel, some of them can be considered semi-hard. The reason this stuff matters is because the tool differs for the kind of material you're turning; not so much the shape, but the angles. So, is there a tool that will work with all CRS AND tool steels like O-1/W-1? Yes, you can make a tool that will work with both, although there will be some compromises. I doubt you'll be able to tell the difference between a tool optimized for either group unless you were doing big runs of stuff.

Before we discuss tool angles, know that a knife tool works well for facing primarily or very light finishing cuts. As you've noticed, it is not intended to be a good turning tool. For that, a general purpose shape works much better and the reason is the end cutting edge on the general purpose tool. You'll note that while a knife tool has an end cutting edge, it doesn't really contact the work in use; all the cutting is done by the side cutting edge and the nose radius. A knife tool can take a big roughing cut but it won't finish well because there is no end cutting edge to provide the finish ... make sense? In contrast, a general purpose tool has a side cutting edge and nose radius that takes the bulk of the material off and an end cutting edge that shears a nice finish, and that is why it works better for turning! Who knew?

A general purpose tool like our square tool is a really good shape. It can rough, face or finish depending on the lead angle you use and it can turn into a shoulder, which makes it really useful for most lathe work. However, the relief and rake angles you use determines which material it will work well with. Fortunately, I've gone over most of this in this thread so I don't need to re-write it. What I will do is give you the angles you need for a tool that will work well with harder steels (1144, O-1) and you can read more about it in this thread for the rationale. I will use the shorthand we've unofficially developed here and that should be enough for you to grind the tool/tools you need.

*Shape:* I would recommend a *general purpose shape*, just like our model square tool.
*Relief angles, both side and end*: If you look at a tool grinding table, you will see that the relief angles for machine steels and tools steels is about 10 degrees. To reduce cutting forces without sacrificing edge life too much, I would suggest using *12 degree relief angles for both side and end*. This means that you will angle your tool rest to 12 degrees (instead of 15 degrees for a square tool) and grind the side and end cutting edge angles without changing the tool rest angle.
*Side rake*: To reduce cutting forces and keep temps lower, I would use *16 degrees* of side rake instead of the recommended 12 degrees. While a 4 degree change might seem small, it will reduce cutting forces significantly, especially when combined with increased relief angles. Moreover, it will not impact on edge life much at all and will reduce the tendency to work harden the material. This matters a lot because high carbon steels like to work harden on you if local temps at the point of cut get too high. Increasing side rake will get the chips out faster, thereby lowering the temp at the point of cut.
*Back rake*: Depending on which steel you're turning, back rake can really vary. However, a reasonable back rake would be around *14-16 degrees (I would use 15 degrees)*. This will put the cutting forces near the tip, accelerate chip flow, thin the chip and enhance finishes ... all in one single angle change.
*Nose radius*: I highly recommend you use a *1/64"* nose radius. Going bigger will only increase deflection in harder steels and with the amount of back rake on this tool, it will still finish nicely.
My personal tool for semi-hardened steels is made with these angles and it works well, at least for me and my lathes. Not sure how it will work for you and your lathe. The only way to tell is to grind it and see for yourself. If you can, show us a picture of it and we'll critique it for you. Now, now, don't be shy!  

As for the boring bar thing, let me PM you about that. I have something that should provide some food for thought.

Regarding the tool bits that are used either straight or angled at the end of a bar and held in place with a set screw, think about how the tool contacts the work. What you have is essentially the same as a left hand turning tool moving into the work, right? So, just grind the tip like a LH lathe tool will look and it will work just fine; trust me, it will work. For a general purpose tool that will cut most stuff, grind a LH square tool shape at the end of the blank.

As for the brazed carbide tool used in a fly cutter, any LH turning tool will work but try to choose one with the side cutting edge angled back a bit. This is called a BL tool and the angled side cutting edge enters the work gradually, which is good for the interrupted cuts encountered when fly cutting. If you can, use one made with C5 for steel. It will look like this:




Put a small nose radius on it  with a diamond stone and it will work okay for you. If you choose to grind a HSS tool, do as @ttabbal  said and try a LH square tool with a 1/32" nose radius; bet it will finish better than that carbide tool.

Your lathe sounds like a good one, Brandon, and you have the experience to use it. I have no doubt it will work with carbide or HSS tooling and there is room for both. You already know how to use carbide. Learn to grind HSS so you have the option.

Okay, long post but I think I covered most of the points. If I missed something important, point it out so I can address it.


----------



## mikey

9t8z28 said:


> Just curious, what kind of inserted flycutter tools do you use, meaning what insert do they take and is the insert neutral?



Sorry, missed this one.

I use a Tormach Superfly that uses positive rake inserts - SEHT1204AFFN-X83 for aluminum and SEHT1204AFSN-X45 for steels. 

I also use a Sherline inserted carbide flycutter that takes CPMW 3251 inserts on my Sherline mill and my RF-31 mill. Leaves an incredible finish and is essentially a single insert face mill. Love this tool!



9t8z28 said:


> Sometimes I do more reading and learning than I do posting!



So do I, believe me. Every single person here does something for a living and many are experts in their respective fields that usually just happens not to be machining. It is the height of arrogance to speak to anyone here with disrespect just because you are a machinist or know more about it than they do; in their own field, they would kick your butt! I respect every single member here, every one.

And then there are the guys like RJSakowski that blows you away with his understanding of physics and chemistry, or Mark Jacobs when discussing VFD's or Bob Korves and shapers or Tony Wells and the other pro machinists who offer sage advice to keep us grounded. So many smart, talented people here and yeah, I happily learn from them every day and am grateful for the opportunity.


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## jwmelvin

mikey said:


> As for the boring bar thing, let me PM you about that. I have something that should provide some food for thought.



I was eagerly awaiting your thoughts on this!  maybe you would send me the PM too as I need to equip myself for the Criterion head I bought.


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## ttabbal

jwmelvin said:


> I was eagerly awaiting your thoughts on this!  maybe you would send me the PM too as I need to equip myself for the Criterion head I bought.



After reading and thinking, and talking with @mikey, I bit the bullet and picked up a set of Borite Cobalt bars. BH500 for 1/2" shank bars. Not cheap, but very good quality. I figured I bought a nice boring head, might as well get quality bars. 

If you want to try them, LMS sells a similar looking import set. I can't say anything about them as I haven't used them. The cost difference wasn't enough for me to pass up known quality. 

The brazed carbide import sets are everywhere and cheap. From what I have read, a lot of people hate them though.


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## Bob Korves

ttabbal said:


> The brazed carbide import sets are everywhere and cheap. From what I have read, a lot of people hate them though.


The biggest problem with the brazed import boring bars is that they are often not ground correctly.  The carbide itself may not be top notch, but it is quite useful, in my experience.  The grind looks OK at first glance, but often the clearance angles are not correct, making them rub on the work instead of cutting, especially in minimum diameter holes for the size of the bar.  Those issues can be pretty easily corrected with a proper grind for the work at hand, but grinding and honing tools capable of handling carbide and leaving proper geometry and a nice sharp edge are needed, along with operator skill, to make them correct.  Some of us don't want to mess with that, and want perfect tools out of the box, which is fine, but leads to throwing them away when dull, using them when dull, or regularly buying new ones, which can get pricey for quality bars.  Which brings us back to the reason for this thread of 785 posts so far -- we need to know how to do it ourselves, and then we can simply (and proudly) do it ourselves!


----------



## mikey

Bob Korves said:


> Which brings us back to the reason for this thread of 785 posts so far -- we need to know how to do it ourselves, and then we can simply (and proudly) do it ourselves!



Well said, Bob, very well said.


----------



## mikey

There are all kinds of boring bars, both commercial and shop-made. I've tried most kinds - brazed carbide, inserted carbide, cobalt, HSS, commercial cobalt, commercial HSS and home-ground HSS on both the lathe and in a boring head. After awhile, you sort of come to some personal conclusions for what works for you and what doesn't, and it won't necessarily agree with what others found for themselves.

When it comes to boring, I hate boring something twice. I want it on size with straight walls and a clean finish the first time. I find that I get these results on the lathe most easily and often when I use carbide shanked bars, either inserted tip for larger and deeper holes or solid carbide bars for smaller holes.

On the mill, them danged centripetal forces influence my tooling choices. I find that at the speeds I can run with the mills I have, carbide is not a good choice because I can't run slow enough and still get a really nice finish. If I run fast enough for a good finish, I get too much vibration. Cobalt bars, on the other hand, finish really nicely. They are very sharp and bore accurately at the low speeds I can run at so, for me, this works the best. There are work-arounds for dealing with centripetal forces; I just have to get off my lazy butt and do it. In the meantime, Borite cobalt bars work for me so I'm with @ttabbal on this one.

I do admit that those cheapy Chinese brazed carbide bars come in handy in a boring head or the lathe on occasion. If you get and keep them sharp as Bob said, they actually work rather well. They will not finish as well as a good bar but for rough work they actually do better than a $10.00 set has any business doing. If I was a new guy, I would buy a set of these tools and spend some time with a diamond stone to sharpen and hone them, then learn to bore with them. The shanks of these tools may be either too soft or too hard but they will still teach the fundamentals of boring quite well.


----------



## mickri

This thread is really great.  The only problem is that it has become so large that it is unwieldy to use and hard to find stuff.  One thing that I would find to be very usable is if there could be one place on the forum where the basic information in this thread could be presented.  I am thinking of  drawings, not pictures, of the different types of tool bits with the angles for the tool.  My lathe came with a chart to be mounted on the wall for quick reference for the basic tool bits.  It really helped me with grinding tool bits.  I couldn't scan the entire chart do to it's size.  A portion of the chart is attached. 

I would be willing to do the drawings.  I use google sketchup for drawing.  Sketchup drawings are 3D  that I would then convert into a jpg  showing top, bottom, side and front views that could be uploaded to the forum.

No forum that I have been on allows sketchup drawings to be uploaded.  If the actual sketchup drawing could be uploaded then the drawing could be viewed in sketchup where you could rotate and spin the drawing to whatever angle you wanted for viewing.  Sketchup is a free program.

Just a suggestion.


----------



## mikey

mickri said:


> This thread is really great.  The only problem is that it has become so large that it is unwieldy to use and hard to find stuff.  One thing that I would find to be very usable is if there could be one place on the forum where the basic information in this thread could be presented.  I am thinking of  drawings, not pictures, of the different types of tool bits with the angles for the tool.



This thread has sort of taken on a life of its own and has become OUR thread, not MY thread. That has been really cool to watch and I couldn't be happier. However, it is huge and I agree that finding specific information can be tedious. Luckily, @DHarris did a Word Doc containing the gist of it. If you would like to compile a set of drawings that you can add here then that would make this thread a really nice resource. Or you can compile it and put it into the downloads section for guys to access. Either way, I think its a great idea and thank you for the offer!


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## 9t8z28

I agree with you. I find myself jumping from page 27 to pages 4 and 5 constantly while grinding these tools.   I think most people will read the first page hoping to find the information and not want to go through 27 pages to find the answers but then again there’s a lot more information in here then just on grinding the specific tools.  Just so you know and everyone else knows, the majority of information you’re looking for is on page 4 and 5.  


mickri said:


> This thread is really great.  The only problem is that it has become so large that it is unwieldy to use and hard to find stuff.  One thing that I would find to be very usable is if there could be one place on the forum where the basic information in this thread could be presented.  I am thinking of  drawings, not pictures, of the different types of tool bits with the angles for the tool.  My lathe came with a chart to be mounted on the wall for quick reference for the basic tool bits.  It really helped me with grinding tool bits.  I couldn't scan the entire chart do to it's size.  A portion of the chart is attached.
> 
> I would be willing to do the drawings.  I use google sketchup for drawing.  Sketchup drawings are 3D  that I would then convert into a jpg  showing top, bottom, side and front views that could be uploaded to the forum.
> 
> No forum that I have been on allows sketchup drawings to be uploaded.  If the actual sketchup drawing could be uploaded then the drawing could be viewed in sketchup where you could rotate and spin the drawing to whatever angle you wanted for viewing.  Sketchup is a free program.
> 
> Just a suggestion.


----------



## Z2V

9t8z28 said:


> Thanks Z2V.  I dont want to jack the thread but I think I saw a CTS-V in one of your photos earlier on in this thread?   I think it was around page 4 or 5 that I saw the photo.   I have almost read every page of this thread. I think I’m up to page 22.   I am trying to absorb every bit of information from everyone that has posted here !




Yeah, I sold a Z06 and purchased the CTS-V, Z2V was born. Great car.
Again, welcome to H-M


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## 9t8z28

Nice!  I had a V as well.  It had more mods than factory parts.  Never should have sold it.  Thanks for the welcoming


Z2V said:


> Yeah, I sold a Z06 and purchased the CTS-V, Z2V was born. Great car.
> Again, welcome to H-M


----------



## 9t8z28

OK here are the pictures of my LH and RH knife tools and the RH square tool.
I spent the most time on the RH Square tool because the first one I made I screwed up royally.   I got distracted by someone talking to me and I wound up taking off to much material on the back and side rake.  I couldn’t stand the fact that the tip was halfway down the 3/8” thickness of the Circle C tool so I made another one.   I made sure that the angles  on this one were dead on Especially the 16° Side rake and the 15° back rake.    I particularly made sure that the angle was not just in the center of the rake but throughout the entire rake angle.   I’m sure anyone who knows what it’s like grinding on a 6 inch grinding wheel, you get the radius of the wheel in the tool, especially when the wheel is worn down quite a bit.   This tool is made from a piece of 1/2” Fagersta WKE 4 .002.   This is some really really tough  material  and it’s very hard to get a sharp corner. I switched between five or six different stones and getting it flat and smooth and finally I finished with a white india stone and a fine diamond stone.   I’m sure an extra fine diamond would get a better finish but I think this is going enough for now until I get one.   There are no reflections of lights on any of the corners.
For the grinding tools I used a craftsman 6” Block grinder, a Harbor Freight 4x36 belt sander (80 grit belt I think) which also has a with a 6” disk which I had a 80 grit pad on.   It’s really a piece of junk but it works.   I am using a gator back Belt which has held up really well.   The 6 inch pads are Harbor Freight sanding pads and they wear out really quick but the dull sandpaper gives a really good final finish.   I also modified the belt portion so that I could grind the back rake and side rake.   I basically cut a section out of the side so I could get the tool on the side of the belt.   I believe someone on here posted the mod  so I can’t take credit for it.   I have on order the belts that Mikey recommended from Amazon and will have them shortly.
Anyway, back to the tools.  The 3/8” knife tools are no where near as nice as some of the ones posted on here bit I am very very pleased with their performance.   I think they work perfect for my expectations and I get a beautiful facing cut wiith them.   They can take very small cuts and I’m very impressed with that. Maybe I should add more nose radius to these tools ?   Anything else I should do to them?   Don’t mind giving me your opinion even if it means telling me they look like crap, I can take it and would appreciate your honest opinion
From left to right: RH knife tool, RH square tool and LH knife tool


----------



## 9t8z28

Here are some more pictures of the RH square tool as I thought there were too many in the post


----------



## 9t8z28

As I stated previously the LH and RH knife tools are made from 3/8” Circle C.   This seems to be really good HSS and was pretty easy to grind. Also it was relatively easy to get a very sharp edge. The RH square tool is made from 1/2” Fagersta WKE 4 .002.  ( i’m not sure what the .002 stands for).   Even though this was half-inch material it was very hard to grind.   The grinding wheel kept loading up and I had to clean it a few times.   I know I was not pushing it too hard into the wheel because I never let the tool get too hot, I took my time on this one.   It is hard to get this material sharp as well.  I have not tried it yet but I think it will hold an edge very very well.   I will be going to the shop shortly and will make my first cut with it and post back here.


----------



## mikey

I'll make some comments but let me preface them by making something clear to you and everyone else. Your work piece doesn't know or care what your tools look like, and your lathe only cares about what your tool angles are. Many of us are grinding on small bench grinders or belt sanders; not everyone has a cool 2 X 72 and this will impact on the quality of the tool - can't be helped. Add to that the fact that for many of you, this is a new endeavor and your brain is still learning how to move your hands to produce a working tool. Please do not compare your tools to anyone else's efforts, including mine, because it doesn't matter.

Okay, your square tool came out really, really nice. All the angles are there and you stopped the rake angle grind at exactly the right place so that the tip is at the same height as the shank - good job. Your nose radius is on the large side but not overly so. This tool will cut well, for you, Sir, and I think you did great! I honestly don't think I could have done that tool much better.

Your knife tools are a bit rough but again, the angles are there and those tools will work for you. I know they will because my early knife tools looked very much like them and they could shave off a few tenths on tool steel. I cannot see a nose radius on them but I can barely see one on mine; as long as it is there then it will work for you. In time, they will look nicer but I'm not sure they will work better.

This stuff takes practice. It took me a very long time to make tools that actually look like lathe tools. Not everyone has the talent to grind tools right off the bat like Jeff, Travis, DaveH, Brino, HBilly or Barry. If you ask me, those guys are mutants. For us regular guys, Brandon, I think you did great. More than that, I bet your tools will work just fine and your grinding efforts will only get better with time. 

My suggestion is to work at understanding how the tool angles work and how you can adjust them to do what you want them to do. The shape of a tool only determines function; how well it works depends on the tool angles. The other thing to consider is making/buying a good belt sander if tool grinding is something you intend to stick with. If you go that route, consider a 2 X 72. It will be good for tool grinding but it will be even more useful for general shop use and fabrication.


----------



## ttabbal

I suppose there are worse things to be a mutant over..  I do think I should be able fly or something though. Bit disappointing.  

Build a 2x72 and blame @mikey for it. I did my first model copies in keystock on a HF belt/disc sander. Even with 36 grit ceramic belts I wasn't a fan. The same type of belts in a 2x72 chew up HSS faster than the HF can work keystock. And with less heat. I was shocked the first time I ground a bit on it. I thought I had been had by the seller of the bits and they sent me aluminum or something. 

I don't claim any great talent for grinding. I blame @mikey for great instructions and having models in hand to look at.


----------



## mickri

Mikey and I exchanged a few emails regarding me doing some drawings of the common tool bits.  He thought that I should post my drawings.  I did the drawings in Google Sketchup.  Then converted the drawings to a jpg image.  I can't upload the sketchup files.  If anybody would like a copy send me a pm.  All of the angles are what Mikey set forth on page 4 of this thread.  I did the drawings using 3/8 x 3/8 x 3."  While the actual drawings are to scale I doubt that the jpg images are to any particular scale.  I did not attempt to round the point.  Sketchup won't do a 1/64 radius.  Hope these are helpful.

Based on comments I have edited my drawings to include the angles used and removed Mikeys angle table.   The area ground for side clearance is shown in red.  The area I am calling "end clearance" is shown in yellow.  I did some searching looking for what people called this and nobody seemed to have a name for this except for one video that referred to it as the "end." I thought that was a good description.  Referring to the side rake and back rake as "top side rack"  and "top back rake" is more descriptive to me.  This portion of the drawings is shown in blue.


----------



## 9t8z28

I just got done turning the OD of the 1018 CRS from .875” to .815”.  This portion that I turned down is the head of the slitting saw arbor.  I am still unable to get a decent surface finish although I will admit that the square tool gave me a better finish than I was able to get with any other tool.  I tried varying depths of cuts, feeds and speeds, I turned the tool in all sorts of directions and I even played with the height a little bit.   I don’t know what’s going on here.   Did I put too much of a nose radius on the tool?   What’s got me even more perplexed  s that the surface finish will change during a cut.   I get this weird finish almost like the way some CRS has that factory pitted appearance.   Sometimes it seems like I hit a hard spot as well.   When I hit the hard spot sometimes I actually get a brighter finish but only for an 1/8” or less.   I am thinking that I need to modify the angles on this tool but I don’t know where to go with it.   Or it could be that this material is of cheap quality and there’s no getting it better unless I finish it with some sandpaper.  
 Anybody have any thoughts.?   
 Here  is a photo showing the best finish I was able to achieve.   1” from the left side towards the center you can see a dull ring where there appears to be a hard spot in the material.   Sometimes I see it after a pass and sometimes I don’t.  
 Sorry if I should be posting this somewhere else.   I feel like I’m beating a dead horse on this subject.  



 Here is a photo showing 3 spots that I think are hard spots.   The tool I was using is an AR Warner T15 HSS insert.   I tried this for a few passes at different angles, speeds, feeds, etc.   I also have a smaller nose radius T15 insert as well as carbide inserts but that’s not intended to discuss here.


----------



## mickri

The people who actually know something about this will chime in here.  I would start by looking up the surface speed per minute for the type of steel that you are turning.  Then look at feed rates and depth of cut.  The MOLO has some of this stuff.  The machinists handbook would probably be the best resource.  Then move on to the shape of the tool bit.  Wish I could offer more help.


----------



## 9t8z28

Yup, already know sfm.  Around 90 for roughing and as high as 250 for finishing.  I was all over and in between plus the DOC was figured and was all over the place as well.  
Now that I think about it, 1018 isnt the most notable for good finishes.  I should retract my previous statement and worry about other things.  These tools work exceptionally well on the majority of materials.  


mickri said:


> The people who actually know something about this will chime in here.  I would start by looking up the surface speed per minute for the type of steel that you are turning.  Then look at feed rates and depth of cut.  The MOLO has some of this stuff.  The machinists handbook would probably be the best resource.  Then move on to the shape of the tool bit.  Wish I could offer more help.


----------



## mikey

Sitting in the ER with my wife right now so I can't give much feedback at this time. Basically, 1018 doesn't finish well, regardless of the tool. Your best shot is to angle the tip towards the tailstock, increase speed and take light cuts.


----------



## mikey

Brandon, 1018 really sucks when you need a good finish. I know of no other material that is worse for that than 1018. About the best I've been able to do with it is to cut it with the side or end cutting edge just adjacent to the nose radius, taking very light cuts at the highest speed my lathe will go and manually feeding it. 1018 often has hard and softer spots so your bands are not surprising. I avoid this material unless I just need something made of steel. I haven't bought it for many years because it is so difficult to finish.

If you need an alternative material, try 1144 Stressproof - better steel for most uses and finishes really nicely.


----------



## mikey

mickri said:


> Mikey and I exchanged a few emails regarding me doing some drawings of the common tool bits.  He thought that I should post my drawings.  I did the drawings in Google Sketchup.  Then converted the drawings to a jpg image.  I can't upload the sketchup files.  If anybody would like a copy send me a pm.  All of the angles are what Mikey set forth on page 4 of this thread.  I did the drawings using 3/8 x 3/8 x 3."  While the actual drawings are to scale I doubt that the jpg images are to any particular scale.  I did not attempt to round the point.  Sketchup won't do a 1/64 radius.  Hope these are helpful.



Thank you for the drawings, Mickri. Some of us are visual learners who will find the drawings very useful.


----------



## mickri

Mikey,  You mentioned being in the ER with your wife.  I hope all is well.


----------



## 9t8z28

Sorry to hear that.  Hope everything is ok.  


mikey said:


> Sitting in the ER with my wife right now so I can't give much feedback at this time. Basically, 1018 doesn't finish well, regardless of the tool. Your best shot is to angle the tip towards the tailstock, increase speed and take light cuts.


----------



## 9t8z28

mickri,  I think the drawings look excellent.   I studied them in comparison to how I thought that Mikey describe them and how I grinded them and they appear to be spot on.   I think these are an excellent visual aid to go with Mikey’s specs.
Could you somehow match the colors with the degrees in some form of a little chart?
EDIT:  If matching the colors with the degrees is to much to do then it would be nice to have a listing with the back rake degrees, side rake degress and so just to keep it all in one place.


----------



## 9t8z28

Thanks Mike.  
 I have been wanting to make a 2x72 belt grinder but I am unsure on how to go about it.   I haven’t really done to indepth research but I probably wil eventually.    It would be a very useful tool and after its built I would probably not use the 6” grinder as much.  
 I agree with you that grinding is all about developing muscle memory.   I can still remember working in shop class when the teacher had us all grind a turning and threading tool.  We all stood in a circle behind the teacher watching him grind the tools.  Not one of us had a good view of what he was actually doing.  Out of the whole class I had the most experience grinding tool bits so I wound up teaching and coaching half the class on how to do it.  Some toolbits were ground down to a stub!  The teacher tried to tell a few students that they got their HSS toolbits too hot and ruined the hardness and had to start over with a new tool.  I argued with him that if it was possible then a 1/4 of the class would have had 2nd to 3rd degree burns on their fingers!  



mikey said:


> I'll make some comments but let me preface them by making something clear to you and everyone else. Your work piece doesn't know or care what your tools look like, and your lathe only cares about what your tool angles are. Many of us are grinding on small bench grinders or belt sanders; not everyone has a cool 2 X 72 and this will impact on the quality of the tool - can't be helped. Add to that the fact that for many of you, this is a new endeavor and your brain is still learning how to move your hands to produce a working tool. Please do not compare your tools to anyone else's efforts, including mine, because it doesn't matter.
> 
> Okay, your square tool came out really, really nice. All the angles are there and you stopped the rake angle grind at exactly the right place so that the tip is at the same height as the shank - good job. Your nose radius is on the large side but not overly so. This tool will cut well, for you, Sir, and I think you did great! I honestly don't think I could have done that tool much better.
> 
> Your knife tools are a bit rough but again, the angles are there and those tools will work for you. I know they will because my early knife tools looked very much like them and they could shave off a few tenths on tool steel. I cannot see a nose radius on them but I can barely see one on mine; as long as it is there then it will work for you. In time, they will look nicer but I'm not sure they will work better.
> 
> This stuff takes practice. It took me a very long time to make tools that actually look like lathe tools. Not everyone has the talent to grind tools right off the bat like Jeff, Travis, DaveH, Brino, HBilly or Barry. If you ask me, those guys are mutants. For us regular guys, Brandon, I think you did great. More than that, I bet your tools will work just fine and your grinding efforts will only get better with time.
> 
> My suggestion is to work at understanding how the tool angles work and how you can adjust them to do what you want them to do. The shape of a tool only determines function; how well it works depends on the tool angles. The other thing to consider is making/buying a good belt sander if tool grinding is something you intend to stick with. If you go that route, consider a 2 X 72. It will be good for tool grinding but it will be even more useful for general shop use and fabrication.


----------



## mickri

I chose the colors to make the ground faces show up better.  No other reason.  Mikey did a table of the different angles.  I'll see if I can copy it and add it to the post with the drawings.  I thought about trying to include the angles on the drawings.  I'll see what I can do.

I just tried to include the angles in the threading tool drawing and was not able to show the angles in a way that would be usable.  Was able to add Mikeys table of angles to my previous post.


----------



## mikey

mickri said:


> Mikey,  You mentioned being in the ER with your wife.  I hope all is well.





9t8z28 said:


> Sorry to hear that.  Hope everything is ok.



She got admitted but should be fine. Life throws curves; all you can do is catch them the best you can.

Thanks for your concern!


----------



## mikey

9t8z28 said:


> Thanks Mike.
> I have been wanting to make a 2x72 belt grinder but I am unsure on how to go about it.   I haven’t really done to indepth research but I probably wil eventually.    It would be a very useful tool and after its built I would probably not use the 6” grinder as much.



A number of our guys have built a 2 X 72 since we started this thread and I'm sure you'll get a lot of help here if you ask for it. There is also a lot of info on the net and on YouTube. Building one should not be difficult and the components can either be bought or made in your shop. 

I think it would be a very good idea for one of you to start a thread on "How to build a 2 X 72 belt sander". I have no objection to discussing it here because it is definitely related. However, this thread has become a behemoth already and the info will be harder to access if someone is just interested in building one and not in grinding tools. 

For what its worth, if you haven't ground a lathe tool on a good belt sander then you don't know what you're missing. A good tool rest and a really flat platen make a huge difference in the ease with which the tool is ground and the belt cuts cooler, faster and cleaner. Changing grits takes seconds to do and with your tool rest you are less likely to change your geometry when you use a belt to refine the grind. I ground lathe tools for over 10 years on a bench grinder so I know you can grind a good tool on it but after 20 years on a belt sander there is no question in my mind that it is a better machine for that task, for me anyway. 

Moreover, a belt sander is about the most useful fabrication tool you can own. If you weld, this will make your life so much better. 

Think it over, figure out how to make one and then go and do it. I assure you, it will be a good decision.


----------



## mikey

mickri said:


> Was able to add Mikeys table of angles to my previous post.



Keep in mind that the grinding table in Mickri's post is a table for conventional tool angles. If you own a small lathe, please consider grinding your tools to the angles discussed in this thread instead. You don't have to do that, of course, but I find a modified tool to be much more useful.


----------



## 9t8z28

Correct me if I am wrong but the chart you posted does not list the recommended angles that Mike suggested for these tools.  This chart is a general recommendation for HSS tools, its a baseline of where to start and can be found on google.  In my opinion, we need his recommended angles inserted into a chart like this one or listed in some other form. Also, the angles at which the side relief and end relief are ground on would be beneficial as most do not know where to start with these angles.   The only way we got to these angles was by a given distance from the end.  Maybe the total angle is all we need.  An example would be 80 degrees for the square tool.  I’m not even sure if thats the correct suggested angle.  I think its called the   Included angle.  





9t8z28 said:


> mickri,  I think the drawings look excellent.   I studied them in comparison to how I thought that Mikey describe them and how I grinded them and they appear to be spot on.   I think these are an excellent visual aid to go with Mikey’s specs.
> Could you somehow match the colors with the degrees in some form of a little chart?
> EDIT:  If matching the colors with the degrees is to much to do then it would be nice to have a listing with the back rake degrees, side rake degress and so just to keep it all in one place.


----------



## mickri

Thanks for the comments on the drawings.  I have edited them.


----------



## Downunder Bob

While I'll be the first one to support the philosophy of beginners learning how to grind their own lathe tools and sharpen drill bits. For those of us who were formally trained at a young age it now comes naturally to us, we sometimes wonder how beginners find it so difficult, particularly when they are a little bit older and just getting into the hobby of machining.

There are a few shortcuts that can be taken. As far as drill bits go a variety of drill bit sharpeners are on the market, I even admit to using a drill doctor myself for the smaller sizes, particularly under 1/4"or 6mm, as my eye sight is not what it once was

For lathe toolbits i can recommend the tangential tool holder system from Diamond engineering, this system is so simple and works so well. I use one for all my general turning, and only resort to hand grinding when I have a special purpose tool that I need to make.

The tangential tool holder is simplicity in itself with only one face to grind it's almost impossible to get it wrong. They do provide a grinding gauge but it is almost not needed. Diamond engineering also have a parting off tool and holder that is almost bullet proof..


----------



## 9t8z28

I got my Redline belts today.  What is the stuff you put on the belts to make them run cooler and last longer?


----------



## ttabbal

9t8z28 said:


> I got my Redline belts today.  What is the stuff you put on the belts to make them run cooler and last longer?



Wax lubricant. https://www.amazon.com/gp/product/B00QL52T7U/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

It seems to help when I've tried it with and without. I turn on the belt, then just touch the wax to it. It shouldn't take much.


----------



## 9t8z28

Thanks.  I just tried the 80 grit belt on a 1/2” HSS bit.  I cant believe how efficient it is!   It didnt get hot either! 





ttabbal said:


> Wax lubricant. https://www.amazon.com/gp/product/B00QL52T7U/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
> 
> It seems to help when I've tried it with and without. I turn on the belt, then just touch the wax to it. It shouldn't take much.


----------



## ttabbal

9t8z28 said:


> Thanks.  I just tried the 80 grit belt on a 1/2” HSS bit.  I cant believe how efficient it is!   It didnt get hot either!



My favorite to start the grind with is 36 grit ceramic. It really chews up the metal. I get the shape in place, then switch to smoother belts to clean it up before honing.


----------



## mikey

Downunder Bob said:


> While I'll be the first one to support the philosophy of beginners learning how to grind their own lathe tools and sharpen drill bits. For those of us who were formally trained at a young age it now comes naturally to us, we sometimes wonder how beginners find it so difficult, particularly when they are a little bit older and just getting into the hobby of machining.



Do you think it might have something to do with being shown how to do it by an instructor who then critiqued your attempts and helped you to learn grind a tool? 

Our guys are doing it alone, without an instructor. Given what I've seen in this thread, I think these guys are doing really well.


----------



## 9t8z28

I just ordered it.   Is it like a hard wax or soft wax?   I have something called Nix Stikx that I use on my band saw blade.  Its somewhat soft.  


ttabbal said:


> Wax lubricant. https://www.amazon.com/gp/product/B00QL52T7U/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
> 
> It seems to help when I've tried it with and without. I turn on the belt, then just touch the wax to it. It shouldn't take much.


----------



## ttabbal

9t8z28 said:


> I just ordered it.   Is it like a hard wax or soft wax?   I have something called Nix Stikx that I use on my band saw blade.  Its somewhat soft.



It's quite soft. The tube is like a caulk or grease tube, I just hand push it from the bottom to get a little sticking out, then lightly touch it on the belt. Seems to last for the whole grind. I suspect the stuff you have is quite similar. 

I don't find I need it on the lighter grit belts, I only use it on the 36 for bulk material removal. After that, I tend to use a light touch just to clean things up and prep for honing. It might be more useful for knife making or similar on the other belts as you might need to use them longer.


----------



## mickri

I have absolutely no room in my garage shop for a separate stand alone belt grinder.  So I have been looking at my bench grinder for ways to make it better/easier for grinding tool bits.  There is a medium grit grinding wheel on the right side and a wire wheel on the left.  I think that a wire wheel is the most dangerous tool in my shop.  One slip and it will tear your fingers apart.  I have been wanting to replace the wire wheel for some time with a fine grit grinding wheel.  Recently I have been thinking about mounting a disc sanding wheel instead of another grinding wheel on the left side of my bench grinder.  I have not seen this done before.  I could mount my drill sharpening guide to work off of the disc sander and make a table that could be set for different angles to grind tool bits.  Would the disc wheel need to be balanced?  What else should I take into consideration?

I have also done a drawing of a 6 inch grinding wheel and measured the angles that would be cut depending on the angle of a 3" wide table.  This is what I found.  With the table flat and on the center line of the wheel pushing a tool bit straight into the wheel flat on the table gives an angle of 3.7 degrees.  If I angle the table up by 2.5 degrees the of the cut is 8.6 degrees.  5 degree tilt equals 13.6 degrees.  7.5 degree tilt equals 18.8 degrees.   Because of the curvature of the wheel the angle cut is slightly greater at the top edge and slightly less at the bottom edge.

The current table on my bench grinder is very short and has no tilt feature.   I would have to make a tilting table.  Probably not hard to do.

I am looking for suggestions.


----------



## mikey

Instead of a sanding disc, I would mount a 6" CBN wheel if you want to stay with a bench grinder. CBN is made specifically to grind HSS and it will last for a very long time and stay flat. Sanding discs don't last very long at all grinding HSS and it takes much longer to grind it. A CBN wheel will also allow you to grind your drills.

The other option is to buy a small 2 X 42 belt sander and ditch the bench grinder. The footprint of such a device is as small or smaller than your bench grinder and can be configured to work quite well for tool grinding and most general shop tasks. We had a discussion about such grinders here: https://www.hobby-machinist.com/threads/help-me-decide-on-a-1-x-42-belt-grinder.70410/


----------



## Downunder Bob

mikey said:


> Do you think it might have something to do with being shown how to do it by an instructor who then critiqued your attempts and helped you to learn grind a tool?
> 
> Our guys are doing it alone, without an instructor. Given what I've seen in this thread, I think these guys are doing really well.



Sorry Mikey, I wasn't trying to be critical of the learners attempts, yes they are doing very well. I was trying to comment on how those of us who have been doing it for along time, sometimes forget how we struggled in the beginning. Yes it was much easier having an instructor standing by your shoulder, and then put the tool in a machine and see how well it worked, or didn't.


----------



## mikey

Downunder Bob said:


> Sorry Mikey, I wasn't trying to be critical of the learners attempts, yes they are doing very well. I was trying to comment on how those of us who have been doing it for along time, sometimes forget how we struggled in the beginning. Yes it was much easier having an instructor standing by your shoulder, and then put the tool in a machine and see how well it worked, or didn't.



Thanks, Bob, I misunderstood - my apologies. I've been doing this so long that I could grind a good tool in my sleep but it wasn't that way in the beginning. I would have paid to have someone teach me back then because I remember how horrible I was. To see these guys just jump in and grind a tool is amazing to me.


----------



## Z2V

We would not have done so well without this thread, that’s for sure.


----------



## thomas s

Yes this has been one of the best threads on this forum.


----------



## mickri

Just got back from a weekend checking on my boat and have another project that I have to get done.  So it is at the top of my list.

That project is to cut 1/4 x 28 left hand threads in 316 stainless steel.  The thread only has to be about 1/2" long.  Does the tool to cut a left hand thread need to be the reverse of of Mikeys' thread cutting tool?  What about the angle on the compound?  Does that need to be reversed also?  Never cut left hand threads  before.  Pretty clueless on this.


----------



## mikey

Very straightforward. The process is the same except that *the compound is turned 29.5 degrees toward the tailstock* instead of the chuck and* the lead screw must be run in reverse* so that you're cutting from left to right. Same tool can be used as for right hand thread and it is oriented exactly the same way as for a right hand thread. It is best to *create a thread relief* so your tool has a place to start the cut. Should be simple for you to do.


----------



## mickri

Thanks Mikey.  I will be ordering the 316 stainless and a few other fittings that I need for this project tomorrow.


----------



## mikey

Best to do a trial run if you can, just to get the procedure down, but you'll do fine.


----------



## 9t8z28

I finally received the Tube Wax.  I purchased the same product you recommended.  The tube is 12" long by 2" thick.  I am sure that I now have a lifetime of belt dressing!  Are you sure you pushed up from the bottom?  I cant get it to budge.
Also, on the tube it states that it can be used for sawing, grinding, drilling, tapping, etc.  It appears to be the same product as Nix Stikx but the Tube Wax appears to be a little more thick.  I will trying it on my band saw and maybe some drills although I am lenient to try it for drilling.  


ttabbal said:


> It's quite soft. The tube is like a caulk or grease tube, I just hand push it from the bottom to get a little sticking out, then lightly touch it on the belt. Seems to last for the whole grind. I suspect the stuff you have is quite similar.
> 
> I don't find I need it on the lighter grit belts, I only use it on the 36 for bulk material removal. After that, I tend to use a light touch just to clean things up and prep for honing. It might be more useful for knife making or similar on the other belts as you might need to use them longer.


----------



## ttabbal

9t8z28 said:


> I finally received the Tube Wax.  I purchased the same product you recommended.  The tube is 12" long by 2" thick.  I am sure that I now have a lifetime of belt dressing!  Are you sure you pushed up from the bottom?  I cant get it to budge.
> Also, on the tube it states that it can be used for sawing, grinding, drilling, tapping, etc.  It appears to be the same product as Nix Stikx but the Tube Wax appears to be a little more thick.  I will trying it on my band saw and maybe some drills although I am lenient to try it for drilling.




I've only tried it on the belt grinder, but it works great for that. I'm sure it would work for other things as well. 

Pushing it out was difficult to get started. Once it starts moving, it doesn't take much to do it again. You could probably just put the tube and all on the belt, a little cardboard probably won't hurt anything..


----------



## mikey

These tubes can have severe constipation and getting the wax to move out of the tube can be difficult. Take a heat gun and gently warm the tube and the outer layer will melt and you can push it out with ease. 

I use this stuff for tool grinding, on the metal bandsaw, hacksaw, for drilling and tapping and to ease a sticky drawer. Also good for driving screws into hard wood, too. I even used it on a bowstring when I needed some and didn't have the real stuff; worked fine for that, too.


----------



## mikey

I just corresponded with someone about how a lathe tool is used. He read this entire thread and was still confused about one really basic issue and I am embarrassed that I didn't make it clear enough for him. If it wasn't clear to him then it is likely not clear to someone else, too, and I apologize.

He got that the tool is oriented roughly perpendicular to the work when roughing, and that you can turn it slightly toward the chuck to reduce chatter. He also got turning it more toward the tail stock for sizing and finishing.* What he didn't get was how to orient the tool to size or finish when the work had a shoulder ... DUH!! This is where I screwed up and didn't make it crystal clear.*

When you size or finish a work piece with adequate length sticking out of the chuck, you will have the best result when you turn the tool toward the tail stock. This allows you to cut with the side cutting edge and the corner of the nose radius to produce fine cuts with a good finish. However, when turning into a shoulder you have to turn the tip of the tool well towards the chuck so that the tool is oriented exactly as it is for a facing cut. In this position, the sizing and finish on the long axis of the work is accomplished with the end cutting edge and the corner of the nose radius, while the same function is accomplished on the shoulder (as you face out) with the side cutting edge and the nose radius.

Like all finishing cuts, depths of cut should be on the lighter side because the end cutting edge, when used like this, will increase radial cutting forces because more of the edge is in contact with the work. Lighter cuts will reduce the deflection and your accuracy and fine finish should be the result. It may also help to increase speed (lowers cutting forces) and slow the feed when a fine finish is needed.

I thought I made this clear before but I went back and read this entire thread (!!) and he was right - I didn't make it clear. I apologize to all the new guys who were confused by this because much of our work on the lathe involves turning into a shoulder and you sort of gotta' know this stuff.

This further emphasizes the importance of the end cutting edge and back rake and how they impact on finishes. Every angle on the tool matters.


----------



## mickri

Hones or sharpening stones.  There is a bewildering number of choices.   So far I have been using my big knife sharpening stone.  Not the easiest to use.
First question is grit.  I would imagine a fairly fine grit.  But how fine?  Suitable range?
Second question type of stone????  Diamond?
Third question I'll call style and size.   Something with a handle?  Triangular?  Flat?  Round?  How long?  Do you need an assortment?

What have you guys who know what you are doing found to work well?


----------



## ttabbal

mickri said:


> Hones or sharpening stones.  There is a bewildering number of choices.   So far I have been using my big knife sharpening stone.  Not the easiest to use.
> First question is grit.  I would imagine a fairly fine grit.  But how fine?  Suitable range?
> Second question type of stone????  Diamond?
> Third question I'll call style and size.   Something with a handle?  Triangular?  Flat?  Round?  How long?  Do you need an assortment?
> 
> What have you guys who know what you are doing found to work well?




I've been using these cards, I think it was @mikey that recommended them. 

https://www.amazon.com/gp/product/B00006IIO3/ref=oh_aui_search_detailpage?ie=UTF8&psc=1 

I use all 3 grits, the coarse to remove the grinding marks and/or burrs and radius the nose, the other two to clean up and sharpen. They work great, are easy to use, and are cheap. I lay them down on the grinder rest plate, though just about anywhere will do.


----------



## ttabbal

So, I was trying out some magnetic unkonwnium on the lathe today. The first go with HSS I ran way too fast and ate the tip of the tool. I cleaned it up and it cuts decent now, but could it be better? 

On the left, my 15 degree square tool taking a light cut, 0.004 at 130 RPM. 

On the right, DCMT carbide insert taking 0.020 at 350 RPM. Same feed, 0.0015/rev. 

Both used tap magic for cutting fluid. Chips came off straw color to blue. At 0.030 the carbide was making longer stringy chips, more blue. 

It looks a bit like the pics of 1018 earlier in the thread. Material is about 2.75" diameter. 

I don't need a perfect finish on this stuff, and there's nothing wrong with using the carbide if it works better. But perhaps I can learn something if someone has suggestions for angles or a different tool geometry they think might be a better choice.


----------



## mikey

I would use more speed for both. With harder steels, HSS likes to rough slow and finish fast. By fast, I mean really fast with light cuts. For example, when I turn a 3/4" piece of 1144 on my little Sherline, I am running a finish cut at 2800 rpm. For your  piece, I would try a fine cut at 15-1800 rpm and see what that does.

Carbide also likes speed. Finish depth of cut depends on the nose radius - what is yours? I would also try to increase speed for finish cuts on that piece; try 950-100 rpm and go up as needed. Your tool holder probably has a 5 degree positive rake and is normally used with the tool shank perpendicular to the work but try turning the tip toward the tailstock a little bit. This can really help the finish when taking light cuts at high speed.


----------



## ttabbal

I'll try that, thanks Mike! The carbide has no discernable nose radius.  HSS is about 1/32" going by my gauge set. I'll set the lathe up for high speed range and give it a go. The break at 380RPM is a bit annoying, but, first world problems.


----------



## mikey

Every insert has a nose radius and you need to know what it is. The last digit is the nose radius, usually in 64ths. For example, the nose radius on a CCMT 32.5*1* insert is 1/64", or 0.016". 




I won't go into too much depth on using carbide inserts here but it is wise to know the minimum depth of cut your insert will take accurately and then try to optimize your speed and feed to finish well at that minimum depth of cut. That way, you come in on size AND produce a good finish.


----------



## ttabbal

So, I got up to about 850RPM. I tried a 0.002 diameter cut with my M2 HSS bit. Killed the edge nearly instantly. Perhaps I should try cobalt. 

The carbide is DCMT070204, so 1/64" radius. At the same RPM and feed it does decently with a 0.020 cut, but it throws a shower of red sparks doing it. 0.010 gets blue chips and cuts alright.


----------



## mikey

That material has to be high carbon steel. HSS will cut 4140 with no problem so it has to be harder than that to kill a HSS tool that fast. Did you try slowing your speed to see if you can go deeper?


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## ttabbal

Above about 200 RPM, the edge on the M2 dies fast. The tool gets a flat spot at the contact point. Below that, it does seem to work decently. Though I haven't gotten much depth without damaging the tool.

The carbide seems to be working fine up to about 0.030 with lower speed around 350 RPM. Beyond that, the lathe can stall.

This is my first go at mystery metal. It seems pretty tough. I had less trouble with 304 stainless.


----------



## mikey

I don't suppose you have those files for testing hardness, do you? It would be interesting to see how hard that stuff is. I've only run into a truck axle that behaved the way your material is and it was a bear to cut. In fact, I tossed it. There is some stuff for which using carbide makes the most sense; this is one of them.


----------



## ttabbal

I don't have the hardness testing files. I was actually looking at them yesterday after I did that higher speed test as I am curious what the hardness is like. I have a bunch of it, but I'm not sure I can use it now. I didn't expect it to be this hard to work. Guess I need to think about getting some of those files if I'm going to buy mystery metal. 

Is it possible I hardened it when the HSS blunted the first time? I didn't look for it and the part got pretty hot before I realized it. The HSS was against the OD which looks like it could be hot rolled, so mill scale is a possibility... Guess it doesn't hurt anything to fire up the bandsaw and cut a fresh piece off to check. Use the carbide to get under anything on the outside.. It would be nice to be able to use it. The HSS seemed to work ok on the facing cut, which was the first thing I did as I wanted to drill for a live center. 

I should probably grind a few extra HSS bits to have around for when I do something like this.


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## mikey

HSS will cut most stuff except hardened steel, which will destroy an edge quickly (like it did here). Cobalt tools might work, at least for awhile. If light cuts are producing blue chips then cobalt might last longer.

You can try a common hand file and test it. If it skates, its hardened. The Tsubosan hardness testers actually work pretty good; I have a set and they would tell you which range of hardness you have. 

Since you have a bunch of this stuff it might be worth it to buy a CBN insert and see if your lathe can go fast enough to use it. You would need to take really light cuts because your lathe is not all that rigid but it might work. As for how useful this material is, if you cannot cut it except for 0.006-0.008" DOC then it will take forever to make something out of it.


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## ttabbal

I agree, if I can't take a reasonable DOC, it's not going to be particularly useful material. I'll hit it with a file, and try a fresh piece to make sure I didn't do something stupid.  Maybe pick up a set of those files just to see what I'm dealing with. It might end up at the recyclers if I can't use it. It's making me really appreciate how easy 12L14 is to work with.


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## Profkanz

mikey said:


> In a recent thread by @Darkbluesky, http://www.hobby-machinist.com/thre...tools-ideas-of-what-to-buy.62043/#post-511618, @ttabbal joked about sending me blanks to be ground into lathe tools ... he was joking! But it got me to thinking ... yeah, I know it's not a good thing when Mikey gets to thinking ... but it got me thinking that reading about how a tool is ground and having a decent tool in your hands that you can see and touch are two different things.
> 
> So, what if I ground a set of tools from 3/8" mild steel keystock (just to discourage some bozo from actually trying to cut something with the models) so people could hold it in their hands to look at. You could use them to plop onto your tool rest to see what the rest angles should be and maybe how your hands have to align to grind the tool. You could also buy some keystock and duplicate them for a permanent reference, and then pass them on to the next guy who wants to have a look.
> 
> I'm thinking of making *THREE* sets of these model tools and mailing them out to guys who are interested. We would need to figure out a list if there are more than three guys interested in seeing them, and YOU GUYS need to sort out how to keep track of these things. I would guess one to two weeks of holding time per person would be reasonable and the guy who has them would pay to flat rate ship it to the next guy on the list. Naturally, the only guys who can get on the list would be members of the HM forum.
> 
> As to which tools to include in the set, I'll leave that to you guys. We can discuss it here and see if we can come to some consensus. I will probably write a set of notes with details on how each tool is ground and why the angles are what they are and how you can modify them to better suit your needs; these notes would be posted to this thread.
> 
> I don't know if this is of interest to anyone but on the off chance that it is, let's talk about this and see if we can make it real. I'll spring for the keystock, grind the models and send them out. After that, you guys need to sort out how to get them distributed. The last guy on the list can hang onto them until some other HM member contacts them or you can send it back to me so I can do the same.
> 
> Let me be very clear about one more thing. The models will be of tools as *I* grind them for use in *my* shop on my lathe(s). It is one way, not necessarily the right way or the only way. My hope is that it will help you to find your own way of grinding tools that work for you.
> 
> Thoughts?
> 
> Mikey


When I was still teaching, I made models from 2x2 lumber for students to use as examples. It did seem to help them.
At first I had examples ground from mild steel, but some fool would always try to cut with them. LOL


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## mikey

Profkanz said:


> When I was still teaching, I made models from 2x2 lumber for students to use as examples. It did seem to help them.
> At first I had examples ground from mild steel, but some fool would always try to cut with them. LOL



Several folks have brought up wooden models and I agree it is a good way to show and discuss these tools, especially when you're standing in front of a class. They are big enough to show the angles from a distance and you can color the different faces. The problem I faced was how to do that on the net. I also had to figure out a way to transmit the information while also sorting out how to help them set the proper tool angles on their own grinders, each of which is different. Trust me; I thought about wooden models many years ago but it just wouldn't work for this effort.

I do agree that I thought about someone trying to cut with the models, which is why I used keystock. They will cut but they won't last long!

The physical act of tool grinding is not difficult. What is difficult is to convey understanding of what the angles do and how to grind them properly over the net. A secondary goal was to encourage the idea that conventional tool angles could be modified to enhance tool performance to enable smaller lathes to cut more efficiently and with greater accuracy. It is my hope that we've at least made some inroads here.


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## SonofHarold - Metal Carver

I managed to cut a 5/16 HSS tool for some 6061 Aluminum, at first it was doing really bad, but finally figured out it was the tool hight, Thought I recalled to set it just above center, ending up lowering to be pretty close to or just below center and things starting working at least OK. I think also I was turning pretty slow.. figured I'd do less damage that way if something went wrong. Turning up the spindle seemed to help alot too. Just kind of experimenting with things today... but I think I could make use of the these example learning blanks. Can who ever has them get in touch with me please?
Thanks!


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## mikey

John, send a PM to @Z2V. He will know how to get a set in your hands.

I find getting the tool tip dead on center height works best. For aluminum, I tend to go as fast as my lathe will run. Works for me anyway.


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## SonofHarold - Metal Carver

mikey said:


> John, send a PM to @Z2V. He will know how to get a set in your hands.
> 
> I find getting the tool tip dead on center height works best. For aluminum, I tend to go as fast as my lathe will run. Works for me anyway.


that would be like twice what I was running(?... 700-800 rpm) so like what RPM? even if turning something larger VS say something smaller that 0.500"?


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## mikey

I suppose I should have qualified that statement. Cutting speed for aluminum when turned with HSS is 500-600 sfm. I use the formula, RPM = cutting speed in sfm X 3.82 / diameter of the work. Most of my stuff is below 1" so I tend to go faster. This formula will basically give you a starting point and you can vary speed up or down as needed. When I use carbide insert tooling, I don't even calculate speeds because the required rpm is almost always faster than either of my lathes will go unless I am turning something huge so I just start at max speed, which for my 11" is 2400 rpm.


----------



## SonofHarold - Metal Carver

I think I was running in the low 600RPM range when it seemed to being well, It made a great facing cut, OD looks only fair, but I was kind of fiddling with things during that cut also.. I got up to around 800 but just felt the slightly slower RPM was cutting better. Was using WD40 a cutting fluid and probably not keeping it covered as should. Playing more today as long as I don't get called out for work.


----------



## Highsider

mikey said:


> In a recent thread by @Darkbluesky, http://www.hobby-machinist.com/thre...tools-ideas-of-what-to-buy.62043/#post-511618, @ttabbal joked about sending me blanks to be ground into lathe tools ... he was joking! But it got me to thinking ... yeah, I know it's not a good thing when Mikey gets to thinking ... but it got me thinking that reading about how a tool is ground and having a decent tool in your hands that you can see and touch are two different things.
> 
> So, what if I ground a set of tools from 3/8" mild steel keystock (just to discourage some bozo from actually trying to cut something with the models) so people could hold it in their hands to look at. You could use them to plop onto your tool rest to see what the rest angles should be and maybe how your hands have to align to grind the tool. You could also buy some keystock and duplicate them for a permanent reference, and then pass them on to the next guy who wants to have a look.
> 
> I'm thinking of making *THREE* sets of these model tools and mailing them out to guys who are interested. We would need to figure out a list if there are more than three guys interested in seeing them, and YOU GUYS need to sort out how to keep track of these things. I would guess one to two weeks of holding time per person would be reasonable and the guy who has them would pay to flat rate ship it to the next guy on the list. Naturally, the only guys who can get on the list would be members of the HM forum.
> 
> As to which tools to include in the set, I'll leave that to you guys. We can discuss it here and see if we can come to some consensus. I will probably write a set of notes with details on how each tool is ground and why the angles are what they are and how you can modify them to better suit your needs; these notes would be posted to this thread.
> 
> I don't know if this is of interest to anyone but on the off chance that it is, let's talk about this and see if we can make it real. I'll spring for the keystock, grind the models and send them out. After that, you guys need to sort out how to get them distributed. The last guy on the list can hang onto them until some other HM member contacts them or you can send it back to me so I can do the same.
> 
> Let me be very clear about one more thing. The models will be of tools as *I* grind them for use in *my* shop on my lathe(s). It is one way, not necessarily the right way or the only way. My hope is that it will help you to find your own way of grinding tools that work for you.
> 
> Thoughts?
> 
> Mikey


Reminds me of a practical joke back when industry was still using some tool steel cutting tools.  Occasionally someone would grind up a fake tool from keystock and drop it into his buddies tool box.  Didn't leave much of a mark on the 4140 or 4350 shafting we were machining, but you knew you'd been had.


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## mikey

SonofHarold - Metal Carver said:


> I think I was running in the low 600RPM range when it seemed to being well, It made a great facing cut, OD looks only fair, but I was kind of fiddling with things during that cut also.. I got up to around 800 but just felt the slightly slower RPM was cutting better. Was using WD40 a cutting fluid and probably not keeping it covered as should. Playing more today as long as I don't get called out for work.



What is the OD of your work piece and how long is it? If it is greater than 1.5 - 2 x the OD then you need a live center. It might help us to help you if you show us your tool. It also helps to know what lathe you're using. Wanna' help but need more info.


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## SonofHarold - Metal Carver

mikey said:


> What is the OD of your work piece and how long is it? If it is greater than 1.5 - 2 x the OD then you need a live center. It might help us to help you if you show us your tool. It also helps to know what lathe you're using. Wanna' help but need more info.


Been a busy week and so a little slow to get back to things. The OD was right at 1.125 and I was try to get down to about an even inch. This little project needs no pression so making use of it to learn and work some things out. I think mostly I need more practice grinding tools, a couple of times it I got it looking pretty good then I think the tool gummed up so tried to touch it up on the grinder and it was then way worse. Was working dry and using WD40 seems to help a lot too. right now I'll probably not get much shop time before next week, Granddaugher spending the weekend with us and some house upkeep chores I am going to be kept out of the shop untill at least mid next week.


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## mikey

Pics of your set up and your tool always helps us to help you.

Aluminum is so easy to turn that you should have mirror finishes on facing and turning cuts with very little trouble. If this is not so then let's find out why.


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## mikey

I just found out that all three sets of the model tools have been lost. We do not know who has them. As a consequence, Jeff aka @Z2V, has been making more models and sending them out to folks who need them, and he is doing it on his dime. He has taken the time and expense on himself to send tool sets to a guy in South Africa and another in Canada, so I know there is still a demand for them.

If any of you have these models, please contact Jeff via PM to arrange to return them. 

A BIG THANK YOU to Jeff for all his hard work and generosity.


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## Z2V

Thanks Mike, I’m glad to be a part of this.


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## ttabbal

Nice Jeff! That's great of you to do. If you need another couple sets, let me know. I'll grind some models and send them out. 

I finally made my first Cobalt tool. Really enjoying working with it. Took a 0.001" cut exactly and I nailed the diameter I was aiming for, measured with a tenths mic. I suspect it was half luck, but I'll take it!


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## Z2V

Hey, I’ll take luck any day. Luck builds confidence which leads to repeatability. 
Good job


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## mikey

Hey, you have a good tool and you know how to use it. Where does luck enter the picture? 

I have seen your tools in person, Sir, and I'm not surprised one of them can take a half-thou cut, not at all.


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## mickri

I am starting to plan what I need to make an ER32 chuck for my lathe now that I have the raw material to make the chuck.  I will be cutting an internal 1 1/2 x 8 tpi thread.  Videos on cutting internal threads suggest cutting a groove to the depth of the thread where the thread ends.  I have boring bars that use 1/4" and 1/8" tool steel.  I have both HSS and cobalt in these sizes.  I am thinking of using 15 degree front and side clearances with an 8 or 9 degree back rake and no side rake to make a tool to cut the groove.  Something like this.




Will this work?


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## Z2V

I just looked at the first page of this thread and all I can say is WOW . The participation has been outstanding.
14 months, 29 full pages, 865 replies, and over 55,000 views. I have lost count of how many members that have handled the models but I’m certain it’s well over 30. We have models in Canada, Australia, South Africa and 3 sets still floating around here. Thanks to everyone that’s joined in.
I knew nothing about grinding tool bits when I first saw this thread and now I can  grind a tool that I can make repeat cuts with. 
Mikey, you hit it out of the park with this topic.
Thank You


----------



## mikey

mickri said:


> I am starting to plan what I need to make an ER32 chuck for my lathe now that I have the raw material to make the chuck.  I will be cutting an internal 1 1/2 x 8 tpi thread.  Videos on cutting internal threads suggest cutting a groove to the depth of the thread where the thread ends.  I have boring bars that use 1/4" and 1/8" tool steel.  I have both HSS and cobalt in these sizes.  I am thinking of using 15 degree front and side clearances with an 8 or 9 degree back rake and no side rake to make a tool to cut the groove.  Something like this.
> 
> View attachment 279441
> 
> 
> Will this work?



Yes, it will work. The feature you are cutting is called a thread relief and the depth of that groove should be about 0.003-0.005" deeper than the anticipated minor diameter and about 2-3 thread widths wide. 

The cutter is basically shaped like a parting tool. Unlike a parting tool, thread relief tools need more end relief because the ID is round; 15 degrees of end relief as you planned is fine. I think 5-8 degrees of relief on both sides will be sufficient. You can use zero rake on top and it will cut fine, although 8-9 degrees of back rake will help it cut with lower forces; if you're using a steel bar then this will be useful. 

Good for you, Mickri! You designed a tool and nailed it and you should feel very good about that!


----------



## mikey

Z2V said:


> I just looked at the first page of this thread and all I can say is WOW . The participation has been outstanding.
> 14 months, 29 full pages, 865 replies, and over 55,000 views. I have lost count of how many members that have handled the models but I’m certain it’s well over 30. We have models in Canada, Australia, South Africa and 3 sets still floating around here. Thanks to everyone that’s joined in.
> I knew nothing about grinding tool bits when I first saw this thread and now I can  grind a tool that I can make repeat cuts with.
> Mikey, you hit it out of the park with this topic.
> Thank You



Thanks, Jeff, for all your help. You've been indispensable!

My thanks to all the readers and participants, too. You guys made this thread what it is. You opened your minds to a different way to grind tools and many of you showed those tools, even though that opened you up for criticism; that takes courage. I have seen guys go from tyro to tool grinders seemingly from the get go and that has truly been amazing. And from the comments I've seen here and elsewhere on HM, there is a better grasp of tool geometry than ever before.

So, my congratulations to you all!!

By the way, we are not done here. I still have to grind that shear tool - I haven't forgotten. Life is particularly challenging of late, that's all. I will get to it, I promise.


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## mickri

Do I dare ask what is a shear tool.


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## mikey

A shear tool, also called a vertical shear tool, is a specialty tool used to take a fine cut to produce a very fine finish in most materials. It has an angled vertical cutting edge but has no relief angles so it can only go maybe 0.001-0.003 deep. It is intended only for finishing.

Here is Tubal Cain's video about it: 










I don't own one, nor do I feel the need for one. However, it has been raised enough that I accepted the challenge of optimizing the angles on one and then grinding a finishing tool to compete with it. Then we'll see just how good it is and if my finishing tool can compete with it.


----------



## Aukai

Sorry to hear that things are so challenging....


----------



## Doubleeboy

Shear tool works great on gummy,  garbage steel like 1018.  No optimization of angles needed, just get it in the ball park. Moltrechts description in the shaper section of his book on machining gets it done for me.  I use the same shear tool on my  little 8" shaper and my 10EE, no problem, rough ground the tool using an angle grinder, finish on belt sander.  I don't use it a lot, but for long slender workpieces where flex can be and issue, it works wonders with very light cuts, one or two tenths up to a thou or two.  On the shaper I take heavier cuts but still light by comparison.  Great tool IMO.


----------



## mikey

Aukai said:


> Sorry to hear that things are so challenging....



Thanks, Aukai. I guess its a matter of perspective. I am a full time caregiver for my wife and part time for her Mom and my Mom. Our Moms are in their 90's, don't drive and everything is a crisis but I am so grateful to have all of them in my life, even though every minute seems to be filled, and I feel blessed. 

Ol' Al (Einstein) once said that a life lived for others is a life worth living. Really smart guy!


----------



## mikey

Doubleeboy said:


> Shear tool works great on gummy,  garbage steel like 1018.  No optimization of angles needed, just get it in the ball park. Moltrechts description in the shaper section of his book on machining gets it done for me.  I use the same shear tool on my  little 8" shaper and my 10EE, no problem, rough ground the tool using an angle grinder, finish on belt sander.  I don't use it a lot, but for long slender workpieces where flex can be and issue, it works wonders with very light cuts, one or two tenths up to a thou or two.  On the shaper I take heavier cuts but still light by comparison.  Great tool IMO.



Kept meaning to PM you, Mike. Did you ever buy that 2 X 42 belt sander? If so, how do you like it?


----------



## mickri

Mikey I know what you are dealing with.  I am the sole care provider for my elderly mother who turned 100 in August.  She is joy to have around.  Mom is in relatively good health but getting frailer and needs lots of assistance with the necessities of life.


----------



## mickri

A grizzly belt sander showed on my local CL  I went to grizzly's website to check it out and saw this.  http://www.grizzly.com/products/Grizzly-Combo-Belt-Sander-Grinder/H7760




And wondered how hard it would be to adapt one side of a bench grinder to a belt sander.  Seems like it would be easier to do this than build a belt sander from scratch.  I looked at the parts list and it looked like you could buy all the parts for less than $50.


----------



## mikey

The hardest part will be fabricating the side plate that forms the chassis of the belt sander and there must be some provision for attaching it to the side of the motor. Once you do that, you can order replacement wheels and tracking assembly from Sears.

Or you can buy a 2x48 multitool attachment for almost $300, or you can build a 2 X 72 for about the same money.

You could also just keep an eye out for a Sears belt sander on CL. It will eventually show up.


----------



## Doubleeboy

mikey said:


> Kept meaning to PM you, Mike. Did you ever buy that 2 X 42 belt sander? If so, how do you like it?



Yup, I bought that Dayton, I put better belt on it, have not updated the platen and will have to carve out some pot metal to put coarse belts on as there is not enough clearance.  That said for the $150 I paid it beats the USA built Kalamazoo 1 inch belt sander I have by a mile.  I have been busy around the farm so shop projects have taken a back seat.  Over all I am happy with it for the money.

Best Regards
michael


----------



## mickri

Mikey  Is this the type of craftsman belt sander you suggested I look for?  https://santamaria.craigslist.org/tls/d/craftsman-belt-disc-sander/6717421350.html.


----------



## mikey

Doubleeboy said:


> Yup, I bought that Dayton, I put better belt on it, have not updated the platen and will have to carve out some pot metal to put coarse belts on as there is not enough clearance.  That said for the $150 I paid it beats the USA built Kalamazoo 1 inch belt sander I have by a mile.  I have been busy around the farm so shop projects have taken a back seat.  Over all I am happy with it for the money.
> 
> Best Regards
> michael



Glad to hear it. Hope you are well, Mike.


----------



## mikey

mickri said:


> Mikey  Is this the type of craftsman belt sander you suggested I look for?  https://santamaria.craigslist.org/tls/d/craftsman-belt-disc-sander/6717421350.html.
> 
> View attachment 279495



That is an older model 1/2HP, 1" belt sander. They are getting really hard to find. The chassis is very similar to the more modern, weaker versions and I'm pretty sure the parts from a 2" model will fit it. Sears still sells parts for the 2x42 so I would consider buying that thing and swapping in the wider 2" wheels. Then you'll have a really good belt sander for cheap!


----------



## mickri

The only problem with this belt sander is that it is about 250 miles from me.  I will get to within about 60 miles when I go to my daughter's for Thanksgiving.  If it is still for sale I might have time to drive there.  I will keep looking for one.  Although I do like my bench grinder.  It is doing the job so far.


----------



## danny12

As others have already stated, I am very thankful for this thread. 

Thank you Mikey!!

I do have a question.  Does anyone make a 2x72 belt that will grind carbide.

Thanks Danny


----------



## mikey

You're welcome, Danny. 

I assume you mean brazed carbide. As far as I know, there is no belt that will grind that effectively; you need a silicone carbide wheel for that. Inserts can be sharpened on a diamond wheel.


----------



## danny12

Thanks Mikey, 
that is what I thought but I have been wrong before.  Lol


----------



## mickri

I am going to look at a delta model 31-350 belt sander over the Thanksgiving weekend.  It is a 1x42.  Anybody have any experience with one of these belt sanders?


----------



## mikey

It will work but the belt is a bit narrow. I prefer the 2" belts myself. Just my druthers, though.


----------



## mickri

I don't know what the asking price is on the delta.  It is in an antique/consignment store that I have been in before.  And the only picture doesn't help much either.  It may be worthless junk and or priced out of this world.


----------



## oskar

Got some questions regarding grinding HSS tools

It is suggested a belt sander is better than a grinding wheel. I have no problem with that but how about the 6” disk we have on the side of a belt sander, is this better to use (to me it’s more convenient).

In my area I can’t find the wax grease stick it is suggested to use but I found “Formax F-26 Grease stick” which is not a stick but comes in a tube similar to one we use on a grease gun. The stuff inside is kind of solid and I wonder how do you apply this to the sanding belt. I used a wooden stick to scrape the grease from the tube and applied to the belt and looks fine to me but how much is enough?

If I decided to use my bench mounted grinder which has on one side a 36 grit wheel is it a good idea to apply wax grease on it?


----------



## mikey

Nic, the disc is fine to use but it is going to be very slow to shape tools with. The belt is much faster. In time, you will learn to use the belt with speed and control.

The Formax is like most wax stick lubricants - just expose a bit of the wax in front of the tube and bring it into direct contact with the belt or disc for a few seconds. You do not need a heavy coat for it to reduce friction and heat. It also reduces loading of the belt, which is especially useful when you grind aluminum. You can use it on a grinding wheel as well. In fact, it works for lubing taps, drills, metal bandsaw, hacksaw or just about any abrasive operation. I've even used it on end mills and with flycutters. Give it a go and you'll find many uses for this stuff.

This stuff is available on Amazon Canada: https://www.amazon.ca/Trend-TRENDIW...d=1542229060&sr=8-17&keywords=stick+lubricant

Search for stick lubricant. Most of the products in a cardboard tube is essentially the same thing.


----------



## mikey

mickri said:


> I don't know what the asking price is on the delta.  It is in an antique/consignment store that I have been in before.  And the only picture doesn't help much either.  It may be worthless junk and or priced out of this world.



The old Delta 1" grinders with the cast iron tables were better than the newer, cheaper models. Still, the narrow belt makes it a no-go for me. Moreover, the platen is a thin piece of flexing steel fastened only on one end. You cannot shape metal if the platen is moving around.


----------



## mickri

I figure that I would have to add/modify the platen on any belt sander that I might buy to make it usable.  I found an owners manual online for the Delta and an interesting feature is that belt can be positioned to run on the backside of the platen with the tensioner arm pressing the belt against the platen.  I have also found pictures of a 31-350 with a support running to the top of the platen   Looks like an easy modification to make.


----------



## oskar

mikey said:


> Nic, the disc is fine to use but it is going to be very slow to shape tools with. The belt is much faster. In time, you will learn to use the belt with speed and control.
> 
> The Formax is like most wax stick lubricants - just expose a bit of the wax in front of the tube and bring it into direct contact with the belt or disc for a few seconds. You do not need a heavy coat for it to reduce friction and heat. It also reduces loading of the belt, which is especially useful when you grind aluminum. You can use it on a grinding wheel as well. In fact, it works for lubing taps, drills, metal bandsaw, hacksaw or just about any abrasive operation. I've even used it on end mills and with flycutters. Give it a go and you'll find many uses for this stuff.
> 
> This stuff is available on Amazon Canada: https://www.amazon.ca/Trend-TRENDIW...d=1542229060&sr=8-17&keywords=stick+lubricant
> 
> Search for stick lubricant. Most of the products in a cardboard tube is essentially the same thing.




Thank you Mike for your time, no I know a bit more and hopefully all set to start my grinding soon


----------



## ttabbal

There are good reasons the knife makers use custom built 2x72s, and it's not just knives they are good for. The solid platen is a big deal for metal work. The speed is also important. You haven't ground a tool till you run a ceramic belt at 5000+ SFM. It's a whole different world vs the wood sanders. 

My first keystock models were done on an HF wood sander with a 36 grit ceramic belt. I borrowed the sander from my brother as I didn't have something to make copies of the models and figured it would be alright. It was, but it took forever and the metal got really hot. When I got my 2x72 running, I can do the rough grinds with a 36 grit ceramic belt in a couple minutes, tops. That's on M2. M42 cobalt bits take a little longer, but not much. On keystock, it's seconds. 

It's a bit like the old idea that you can make anything with a pile of metal and some files. You can. But using a lathe and a mill make it a LOT faster.


----------



## WCraig

mikey said:


> Nic, the disc is fine to use but it is going to be very slow to shape tools with. The belt is much faster. In time, you will learn to use the belt with speed and control.
> 
> The Formax is like most wax stick lubricants - just expose a bit of the wax in front of the tube and bring it into direct contact with the belt or disc for a few seconds. You do not need a heavy coat for it to reduce friction and heat. It also reduces loading of the belt, which is especially useful when you grind aluminum. You can use it on a grinding wheel as well. In fact, it works for lubing taps, drills, metal bandsaw, hacksaw or just about any abrasive operation. I've even used it on end mills and with flycutters. Give it a go and you'll find many uses for this stuff.
> 
> This stuff is available on Amazon Canada: https://www.amazon.ca/Trend-TRENDIW...d=1542229060&sr=8-17&keywords=stick+lubricant
> 
> Search for stick lubricant. Most of the products in a cardboard tube is essentially the same thing.



The Amazon product seems to be out of stock.  (And it seems to be designed for lubing saw blades?)  

There are two Formax products are available at KBC Tools:

"F-26"  C$9.80
https://www.kbctools.ca/products/ABRASIVES/COATED ABRASIVES/ABRASIVE BELTS/BELT DRESSERS/755.aspx

"F-90" C$10.15
https://www.kbctools.ca/products/ABRASIVES/COATED ABRASIVES/ABRASIVE BELTS/BELT DRESSERS/752.aspx

Not sure which is the better choice?  (KBC also has a Formax product for lubing saw blades.  "Formax Saw Blade Wax Stick.")

Craig


----------



## mikey

I would think that either would work. I would go for the cheaper one.


----------



## tmenyc

OK, I finally got my first set of maybe-close-to-ok tools ground in keystock.
First, the model set on the left of each pair, mine on the right.





Then, 











Not thrilled with the knife, but perhaps the turning and threading are better?  
All comments pro and con solicited.  Then, I'll do a second set since I haven't been told to send it on.
Many thanks!
Tim


----------



## Z2V

Tim, It looks like you are off to a good start. I’m sure Mickey will stop by soon. Are you using a bench grinder or do you have a belt grinder?
I do not have any members on the waiting list at this time so feel free to hold on to the models.


----------



## thomas s

Nice job it just takes practice and Mikey makes it look easy.


----------



## tmenyc

thanks!  I'm getting the feel for it, it's fun!  I have a bench grinder, no space for a belt.


----------



## mikey

Tim, I agree with Jeff. It looks like you're off to a good start. However, the views are a bit confusing. Let me try to be more specific.

The threading tool view is upside down and we cannot see the upper surface. It looks fine, though, from what I can see and it will work if your tool profile is at exactly 60 degrees.
The knife tool's rake surface is not ground all the way to the tip so it will not cut well. You need to grind it until the grind is fully at the tip and no further. It will cut if you do that.
The turning tool pic is confusing. It shows the tools from the bottom. This makes it hard to evaluate. Not sure what the scalloped side is meant to do. Also, if the tool to the left of that scalloped tool is also upside down then why is it ground underneath? 
I'm probably not seeing the tool the way you intend. Please shoot pics directly from the sides, directly on top and from the tip and we'll go from there.


----------



## tmenyc

got it.  I'll try to in a bit.  Many thanks!
Tim


----------



## tmenyc

How's this? 
Tim


----------



## mikey

Tim, the turning tool and threading tool look pretty good. However, the knife tool needs to be re-done. Go back to page 4, post #104 of this thread and look at how the knife tool is ground. 

The first step is to grind the left side of the tool. You are grinding the side relief angle with the tool parallel to the face of your wheel. As you grind that side, it will cut at the lower edge of the blank and as the grind progresses, the ground part will rise toward the top of the tool. Stop just as the ground part reaches the top part of the tool. This creates the side cutting edge.

Second step is to grind the end at about a 65 degree angle.

Third step is to grind the top rake angles, which you already know how to do. 

Keep at it. You're doing well! Show us the knife tool when you're done with it.

This tool grinding thing is not hard to do but in the beginning, it takes a bit to learn how to move your hands and get your head around what they're doing. Like almost everyone else here, you're doing a heck of a lot better than I did at your stage of the game.


----------



## mikey

thomas s said:


> Nice job it just takes practice and Mikey makes it look easy.



Thanks, Tom. Yeah, its easy for me now but it wasn't always so. I clearly remember how I started and that keeps me humble. You saw my early tools - I just cannot be arrogant about anything after showing you that!


----------



## tmenyc

mikey said:


> The first step is to grind the left side of the tool. You are grinding the side relief angle with the tool parallel to the face of your wheel.
> [/QUOTE When you say "you are grinding" here about the knife tool, do you mean I SHOULD be or did but should  NOT be?
> 
> Mike,
> You're the world's best teacher.   Many thanks.
> Tim


----------



## SonofHarold - Metal Carver

Z2V said:


> Tim, It looks like you are off to a good start. I’m sure Mickey will stop by soon. Are you using a bench grinder or do you have a belt grinder?
> I do not have any members on the waiting list at this time so feel free to hold on to the models.



Grinding good cutting tools been my current stumbling point of late. Had been trying to use some carbide inserts that I had inherted with varriying results and came to the conclusion that due to the size and power of my equipment HSS would do better and be cheaper.(?) I had expressed an interest in the model/examples some time ago but did not follow up on that... SO... not yet sure that'll need them now, Getting a larger 8" grinder tomorrow, only had a weak little 5" and my results were kind of hit and miss. Good to revist this thread and will be trying more again soon.


----------



## tmenyc

You should use the models, and I have extra keystock if you want some.  So much easier when you read the text AND have the model in your hand.
Tim


----------



## tmenyc

Mike,
I reread 102 and 104.  I think part of the problem has been the angle of the tool rest on my grinder.  It's time to get a digital angle finder.  Do you recommend one of the box ones where it just rests on the flat and reads off its angle from flat?  Like this?  Or is there a particular one you prefer?


----------



## mikey

tmenyc said:


> Mike,
> I reread 102 and 104.  I think part of the problem has been the angle of the tool rest on my grinder.  It's time to get a digital angle finder.  Do you recommend one of the box ones where it just rests on the flat and reads off its angle from flat?  Like this?  Or is there a particular one you prefer?



The one you linked to will be fine. Mine is similar, from Beall Tools, but it does exactly the same thing.

The tool rests on bench grinders can give different angles, depending on how they are attached to the grinder. You might want to confirm that a 15 degree angle set by the digital protractor matches the face of the model. If it is off, you can remedy that by making a better stand alone tool rest. Jeff/@Z2V made a good one and he can give you some advice there.

You might also consider a small belt sander at some point. Mine takes up no more room than my bench grinder and it is vastly superior to the grinder for tool grinding.


----------



## mikey

SonofHarold - Metal Carver said:


> Grinding good cutting tools been my current stumbling point of late. Had been trying to use some carbide inserts that I had inherted with varriying results and came to the conclusion that due to the size and power of my equipment HSS would do better and be cheaper.(?) I had expressed an interest in the model/examples some time ago but did not follow up on that... SO... not yet sure that'll need them now, Getting a larger 8" grinder tomorrow, only had a weak little 5" and my results were kind of hit and miss. Good to revist this thread and will be trying more again soon.



John, give it a go with the instructions on page 4. If it doesn't work out and you aren't sure how close you are, contact @Z2V and get some models in your hands to confirm. As Tim said, it can help. Show us some pics if you like and we'll give you an opinion.


----------



## tmenyc

Mike, looking at the Knife Tool presentation again, I'm still not sure all of what I did wrong, but it's a bunch. So I want to make sure I understand. 
The first photo represents the tool at the first cut, the half inch noted in the previous paragraph; that's the first cut. Then the 65 deg line and cut are made as the second cut.  In the second photo you can't see the first cut because it's underneath, correct?  You can just see the edge in the third photo, on the left.  The rake angles make sense, pretty sure. 
I'm looking forward to re-seeing what I did when I get home tonight, think I got it upside down at a minimum. 
Many thanks. 
Tim


----------



## mikey

tmenyc said:


> Mike, looking at the Knife Tool presentation again, I'm still not sure all of what I did wrong, but it's a bunch. So I want to make sure I understand.
> The first photo represents the tool at the first cut, the half inch noted in the previous paragraph; that's the first cut. Then the 65 deg line and cut are made as the second cut.  *In the second photo you can't see the first cut because it's underneath, correct?*  You can just see the edge in the third photo, on the left.  The rake angles make sense, pretty sure.
> I'm looking forward to re-seeing what I did when I get home tonight, think I got it upside down at a minimum.
> Many thanks.
> Tim



Yup, you got it, Tim. You're going to be fine.

The knife tool is a really accurate tool for general and precision facing but it also works good for trepanning if the tip fits. I just used one to bore the bottom of a center height gauge for a friend and it cut stainless steel with a sweet hiss and the final cuts were like airborne pixie dust. Funny how I make tools for friends that are finished to fine standards but the tools for myself look like I used construction tools to make them. I need to treat myself better!


----------



## mikey

tmenyc said:


> When you say "you are grinding" here about the knife tool, do you mean I SHOULD be or did but should  NOT be?



Sorry, I missed this. I mean you* should* be. The side of the tool is oriented parallel to the face of the grinding wheel, so that as you feed the tool into the wheel it grinds the side of the tool blank. As you push the blank into the wheel, the grinding wheel will start to cut at the lower part of the blank. As your continue to grind, the ground part will climb up the side of the blank and approach the top surface of the tool. Stop grinding just as you reach the intersection of the side and top surfaces of the blank. Then move on to grind the end, and then the top rake angles. 

Don't forget to put the tiniest nose radius you can stone on it. Try not to leave a sharp point because it will leave lines in your work and can crack off if you turn with it. A tiny nose radius works best.


----------



## tmenyc

thanks, Mike.  That's what I thought, put the words as if spoken into my head, but wanted to make sure.  It all makes sense.  

Tim


----------



## SonofHarold - Metal Carver

mikey said:


> John, give it a go with the instructions on page 4. If it doesn't work out and you aren't sure how close you are, contact @Z2V and get some models in your hands to confirm. As Tim said, it can help. Show us some pics if you like and we'll give you an opinion.


Well as of today I think I got over the hump. I have to hold touch and see things like this to learn it, and then the reading of details like are here seem to help more once I have done it on my own. I had such good results today following some instructions I just stumbled on a few days ago and now re-reading much of page 4, I don't think I'll need the models, as least not soon. Would it be inappropriate to post a link to the web site? Seems it made it more simple and being very basic, made it easier for me to duplicate the results. Plus... I was just fooling around to give it a practice run through this afternoon and am still quite happy with myself and the results. I'll try and get some pics up tomorrow but I have another mission in the What is it thread for this evening.


----------



## machPete99

Just for reference, at least one of the Tubalcain videos used some oversized wooden models to help show the angles, like this one:


----------



## mikey

SonofHarold - Metal Carver said:


> Well as of today I think I got over the hump. I have to hold touch and see things like this to learn it, and then the reading of details like are here seem to help more once I have done it on my own. I had such good results today following some instructions I just stumbled on a few days ago and now re-reading much of page 4, I don't think I'll need the models, as least not soon. Would it be inappropriate to post a link to the web site? Seems it made it more simple and being very basic, made it easier for me to duplicate the results. Plus... I was just fooling around to give it a practice run through this afternoon and am still quite happy with myself and the results. I'll try and get some pics up tomorrow but I have another mission in the What is it thread for this evening.



Post away. Anything that helps understanding is a good thing.


----------



## SonofHarold - Metal Carver

I started out trying to do this more or less freehand,  I remeber see in the old man do it like that, even sharpening  1/8" drill bits in less than a minute freehand. I 'd try it and the bit would not cut wood.... I guess I though I had inherted the skills. 
Anyway for anyone interested like I said I just stumbled on this the other evening actually looking for some photos to guide me along. The web sight is Blondiehacks- http://quinndunki.com/blondihacks/?page_id=3338 Actually several good projects for the novis to learn with. Thnx again!


----------



## mikey

Whatever it takes to learn this skill, use it. Just keep in mind that knowing how to grind a tool is only part of the process. You need to understand what the angles that you are grinding actually do, and it is even better if you understand how to alter those angles in order to get the tool to do what you need it to do. 

Not to criticize that guy but to make it clear to you, John, about the deficiencies of his tool. 

The angle between the side and end was originally laid out to be 90 degrees; this will not allow the tool to cut into a shoulder and face out the shoulder because the tool will rub. Make yours less than 90 degrees.
 His rake angles are inadequate. He has almost no back rake and I can't tell how much side rake there is but I suspect is isn't much. This tool will cut but it will not cut as well as it could. He needs to fix the rake angles.
His nose radius is huge. That tool will deflect and not cut accurately with very small depths of cut. It may finish okay, though.
Again, I'm trying to point out that the actual grinding of a tool is only a part of the process. You have to understand WHAT you're grinding and WHY the tool is ground the way it is. So, use what you need to use to understand how the grinding process works but learn to grind the tool so that it cuts the way it needs to cut.


----------



## SonofHarold - Metal Carver

I did last evening revist earlier pages in this thread and get that some different angles ect are nessasary for different materials etc. are needed, but I am doing better than I've done previously, I think tho mostly because I trying to do it more free-hand... maybe. 
So if I understand that 10 degree angle obtianed by the angle of the rest to the wheel should be increased?  And I did get that a angle beyond 90 was necessary  and that is how what I am showing in the pics turned out, but only a little better than 90 tho
But here is what I did this afternoon hope these pics are decent enough. Let me know what you think... I will be down in the shop for a while tho. Thnx


----------



## SonofHarold - Metal Carver

mikey said:


> Post away. Anything that helps understanding is a good thing.


I like this video too, and should help. I guess the direction on Blondiehachs were maybe "poor" but still using those and getting repeatable imporved results from what I had done before... I guess what I was doing previoulsy must have been terrible ( at least half the time ) the learning continues...


----------



## mikey

The overall shape is good. 

Your nose radius is a bit on the large side and was ground with the wheel. You will find that a smaller nose radius works better. It is also better to form the radius with a diamond stone so you can control the size and contour of it more precisely.
It looks like your rake angles are okay but look a bit shallow for a square tool. Both back and side rake are sloping in the right direction so you got it!
Did you hone this tool?
I think you did great overall. This is a somewhat difficult thing to learn, especially on a bench grinder. Keep at it and the manual skills will come. You are well on your way, John!


----------



## mikey

SonofHarold - Metal Carver said:


> I like this video too, and should help. I guess the *direction* on Blondiehachs were maybe *"poor"* but still using those and getting repeatable imporved results from what I had done before... I guess what I was doing previoulsy must have been terrible ( at least half the time ) the learning continues...



As I said, if those pics and instructions helped you then they are not poor. Use it if it helps you to learn this skill, nothing wrong with that. I pointed out the deficiencies as I saw them so that you would understand that tool geometry is a real thing. Every single feature on the tool is meant to accommodate or mitigate cutting forces in one way or another, and every feature is purposely ground to do a particular thing. For example, if you need to reduce radial forces, you would reduce the size of the nose radius and boost back rake. If your nose radius is huge and you have no back rake then you may wind up increasing radial forces instead. That is why I pointed out the deficiencies of his tool ...  you can grind a tool but you have to understand what you're grinding.

I meant no disrespect for that guy or you. Far from it. I have been exactly where you, and he, are. I just happen to be in a place right now where I can see tool geometry and can predict how the tool will cut. Anyone can grind a tool; not everyone knows what they're grinding or why they're grinding it that way. I wish for you to understand the what and why; the how will come in time.


----------



## SonofHarold - Metal Carver

mikey said:


> The overall shape is good.
> 
> Your nose radius is a bit on the large side and was ground with the wheel. You will find that a smaller nose radius works better. It is also better to form the radius with a diamond stone so you can control the size and contour of it more precisely.
> It looks like your rake angles are okay but look a bit shallow for a square tool. Both back and side rake are sloping in the right direction so you got it!
> Did you hone this tool?
> I think you did great overall. This is a somewhat difficult thing to learn, especially on a bench grinder. Keep at it and the manual skills will come. You are well on your way, John!


I think after a couple of really bad results I got intimidated/discouraged with it in some way. 
No on honing, how important is it for just practicing? does it make a big difference?   that was done with a 60 grit wheel, just installed a 120 grit today, I also got a print out from page 4 of this thread (no wireless in the shop-yet, and had to cohorse my printering into submission) but am going to be back it for a "bit" shortly. Thanks much!


----------



## mikey

SonofHarold - Metal Carver said:


> I think after a couple of really bad results I got intimidated/discouraged with it in some way.
> No on honing, how important is it for just practicing? does it make a big difference?   that was done with a 60 grit wheel, just installed a 120 grit today, I also got a print out from page 4 of this thread (no wireless in the shop-yet, and had to cohorse my printering into submission) but am going to be back it for a "bit" shortly. Thanks much!



Brother, I totally understand the intimidated/discouraged thing, and I OWN the concept of bad results. Nobody, and I do mean nobody, could start off as badly as I did. The difference is that I didn't let that stop me and I sincerely hope that you don't, either. Tool geometry is not intuitive. To understand it, you actually have to put some effort into it. What we are doing here is to try and make that as painless as possible. If you don't understand something, ask and one of the guys or I will try to help.

Yes, honing makes a difference, at least to me. The cutting edge as ground is a bunch of peaks and valleys that will cut corresponding peaks and valleys in your work. Honing makes those defects much smaller and if you hone the tool well, those defects will usually be too small for the unaided eye to see. Moreover, the cutting edges will last longer, much longer. You should hone your tools to remove all visible grinding marks if you can. Use a diamond stone - works faster.


----------



## SonofHarold - Metal Carver

Thanks much! Success breeds more success, The details and nuances will come in time but I think I am over the hurdle after the fairly decent results I had yesterday and today. Couple more issues to address in getting my shop set up and I want to start making things... not just chips, though there is some strange satisfaction for me in watching a tool cut into material on the lathe and watching the chips fall, so to speak. That was a part of what got me interesting in doing this in the first place. 
I just noticed sir your in Hawaii and as of today it makes me very jealous... in Western PA we have only had like two days of sunshine since Christmas, and for me moving here just a year ago from Colorado, that's tough been... then  imagining you in the warm breezes and blue skies of Hawaii - very jealous indeed! Aloha!


----------



## mikey

Well, its 78 degrees with light tradewinds and sunny. Not a snowflake in sight so no skiing going on but then again, I'm not freezing my butt, either, so there's that. Yup, living in Hawaii is pretty nice. On the downside, we do have hurricanes that try to eat us every year so ...


----------



## tmenyc

mikey said:


> Well, its 78 degrees with light tradewinds and sunny. Not a snowflake in sight so no skiing going on but then again, I'm not freezing my butt, either, so there's that. Yup, living in Hawaii is pretty nice. On the downside, we do have hurricanes that try to eat us every year so ...


and didn't you have a bit of lava flow lately?


----------



## mikey

tmenyc said:


> and didn't you have a bit of lava flow lately?



Yeah, the beach house that we used to go fishing from every year is now under 30 feet of new lava. The Big Island is the newest place on earth. Luckily, the eruption is on another island.


----------



## mcdanlj

Thank you @mikey! I read through this massive thread as closely as I could. Today, I ground a tool for brass and was able to take off a few tenths with a clean finish on over an inch of .250" rod. The first cut I did had an ugly finish. Because of your instruction here, I was able to understand why, fix the problem with a diamond hone, and get a better finish. Then for the last pass, I angled the tool, and got an even better finish. What surprised me even more was that I didn't even bother turning on the DRO, which I previously couldn't have imagined.

On the one hand, I hate to bloat this thread with more ME TOO! posts. On the other, I have to say thanks.

Once I get a belt grinder, I'll probably ask to get in the model tool rotation. In the meantime, I've already benefited tremendously.


----------



## mikey

Awesome! Congrats on your success and yeah, get your hands on the model tools. It will help make grinding the other tools a bit easier. Please keep us posted on how things go for you, okay?


----------



## Z2V

@macdanlj, drop me a PM with contact info and I will get a set of the tool models in the mail to you when you are ready.
These tools definitely can be made with a good bench grinder but a belt grinder makes it so much easier to do. Several of use here have built belt grinders as a result of this thread. I will have to say that the belt is now probably the most used tool in my garage. You can’t go wrong.


----------



## mcdanlj

@Z2V For sure! I'll ask either when I have a belt grinder or when I run out of patience, whichever comes first. When it comes to "good bench grinder" — I have a Northern Tools Ironton cheap ½HP 8" grinder that I bought years ago to sharpen lawnmower blades and such. I did put better wheels on it for grinding tools than the wobbly junk wheels it came with, but it bogs down when I'm cutting. Better diamond hones and arkansas stone are my next purchases here, I think, as I decide whether to buy a belt grinder kit or build from scratch. I did order the set of 50 3"x ⅜" blanks from CME, which is still available for $64 shipped.


----------



## Bob Korves

Here is a well done and high quality video from Adam Balogh of Machine Tool Blog, part one of an expected five video series, on grinding cutting tools.  The visual experience along with spot on information may be something that many on this thread will find useful.  Adam is a friend of Tom Lipton (YouTube channel oxtoolco), and both are managers of separate departments at Lawrence Berkeley Labs in Berkeley, CA.  Adam is also a teacher of machining at Laney college in Oakland, CA.  Adam has some other interesting YouTube machining videos on his channel that many of you may enjoy, check out and subscribe to his channel: https://www.youtube.com/channel/UCQfMyugsjrVUWU0v_ZxQs2Q.  Adam's channel has been quiet for some time while he and his wife had their first child, looks like he is back and ready for more.  I met Adam at a Richard King scraping class.  Adam lays out the information like a fire hose, don't be afraid to rewind as necessary to get it all:





Edit:  Adam sent me the worksheets that his students get to answer for the first two videos.  They will probably make you watch the videos again to get the answers correct.  I will too...  Adam also told me he left his job at Lawrence Berkeley Lab to teach machining full time at Laney college.  Shows where his heart is...  Here comes the first worksheet:
NAME *___*

Video Worksheet – “Grinding Cutting Tools – Part 1”

Watch the Machine Tech Video Blog video on “Grinding Cutting Tools – Part 1” on Youtube.com.

Answer the following questions based on the information presented in the video.

1) Fill in the blank: The cutting tool causes the material to deform by *____*.

2) Fill in the blank: The final shape of the workpiece is determined by the tool’s

* and its *

3) What are the six critical angles on a single-point cutting tool?

4) What is the purpose of the tool nose radius?

5) What are the two main categories of cutting tools for the lathe?

6) What are the three required criteria for a cutting tool material?

7) What are the three most commonly used grades of high speed steel?


----------



## mikey

Thanks, Bob! This was a superbly done video and I especially liked his Samurai intro persona - very cool guy! I wish more guys were as entertaining while also delivering solid information. Looking forward to seeing him grind tools and will watch the series.


----------



## Bob Korves

Part 2 of the tool grinding video series from Machine Tech Blog




Video Worksheet – “Grinding Cutting Tools – Part 2”

Answer the following questions based on the information presented in the video.

(Fill in the blank) A turning tool is used to machine .
(Fill in the blank) A right-hand cutting tool cuts from to .
What are the two angles controlled when presenting the tool to the grinder?
1)
2)
4) The tool will be ground using the following sequence:
1)
2)
3)
4)

List the shop tools required to grind the right-hand cutting tool:
What are “The Three D’s”:
1)
2)
3)

To make the grinding process easier, these two aids will be used:
For yaw angles:
For pitch angles:
What works well as a solvent for removing layout fluid and permanent marker?
When stoning the tool nose radius, what should you NOT point down toward the stone?


----------



## tmenyc

I just finished seeing 1 and 2, and it made me completely comfortable to go beyond the keystock models.  incredibly clear and explained.  The combination of Mikey's text and photos and these videos is pretty powerful.  Thanks for pointing them out!
Tim


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## Bob Korves

Adam sent me some worksheets for posts 937 and 949.   I did the best that I could to add them to the posts below the videos.  I am not enough of a nerd to get the PDF's transferred to this site without some changes that also refuse to be edited to actually make improvements.  Use the worksheets to make sure you understand and retain what you saw on the videos.


----------



## tmenyc

You know, it's like the old thing about language, that you'll learn a word for good when you've seen/heard it seven times.  I took notes about what I didn't already know, have built the keystock tests, and think after all the reading, doing the models, and now the videos, that I'm actually starting to understand the concepts. My grinder really needed a better base; it's coming this weekend, and I'm also serendipitously going to the Connecticut shore with my wife this weekend, so will get sand to fill the column.  Then, when the grinder is set up again, I'll take a stab at cutting HSS.


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## mikey

The coolest thing we've accomplished in this thread, and now with Adam's videos, is that we've been able to reach a LOT of guys. It doesn't matter if you grind your tools with my angles or Adam's angles or the angles in a grinding table. What really matters is that you understand what the angles do, know that you can modify them to suit your needs and know how to change those angles so the tool does what you want it it to do. 

It has truly been a privilege to watch you guys grow. I know Adam would feel the same way, knowing that he helped to turn on a light bulb in somebody's mind. Doesn't get better than that.


----------



## Aukai

I know I have read it, but is there a single place to reference the differences in the angle of "attack" for the tool post for different processes for the different tools? Toward the head stock, 90*, toward the tail stock, different finishes, etc?


----------



## mmcmdl

Aukai said:


> I know I have read it, but is there a single place to reference the differences in the angle of "attack" for the tool post for different processes for the different tools? Toward the head stock, 90*, toward the tail stock, different finishes, etc?



Mike , the toolpost angle doesn't really matter , the angle of the tool is what matters . Cutting angle and cutter clearance is most important .  As soon as I get a free night we'll hook up again .


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## Aukai

Sounds like a plan,,,,More accurately maybe tool to work piece angles.


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## Bob Korves

tmenyc said:


> I'm also serendipitously going to the Connecticut shore with my wife this weekend, so will get sand to fill the column.


Don't forget to wash the salt off that beach sand...


----------



## Bob Korves

mikey said:


> I know Adam would feel the same way, knowing that he helped to turn on a light bulb in somebody's mind. Doesn't get better than that.


I am in contact with Adam about my posts of his videos here.  He is jazzed to see the additional exposure of his considerable work in producing the videos, and is pleased that our H-M members have an additional source for learning the skills of grinding cutting tools.


----------



## mikey

Bob Korves said:


> I am in contact with Adam about my posts of his videos here.  He is jazzed to see the additional exposure of his considerable work in producing the videos, and is pleased that our H-M members have an additional source for learning the skills of grinding cutting tools.



Bob, the next time you are in contact with Adam, please tell him how much I enjoy his videos. I love his personality and his skill at teaching this rather confusing and complex topic.  In order to teach a thing you must know the thing and it is clear to me that he knows what he's doing. Furthermore, given the quality of his videos, it is clear that he put in a lot of time, thought and editing to put out such high quality work and it is greatly appreciated.


----------



## Iron-Iceberg

mikey, first I wanted to really thank you for starting this thread. Im new to the lathe and really didn’t know what I needed for tooling. I was thinking about getting some insert tools just so I could get going. But there are so many options I got lost. 
After getting sucked into this thread for days. I decided to just start grinding, and see what happened. It was also pretty economical way to get started.  I made a left and right version of your square tool and a knife tool.
I’ll have to say I’ve trashed the square tool a few times already. But a touch up on the grinder and I’m back in business. Great for a new guy. 
On another thought. I don’t have a belt sander. I have a 20” disk sander. Great tool but the HSS stock just wiped out the edge of the sanding disk. I have seen the ceramic disks but at twice the price I’ve just passed. After wiping out the edge of the second disk I ordered up a new ceramic disk. I have to say WOW!  Not only did it cut the tool great with a minimum heat added to the tool, it just cuts steel great. Normally when I grind an edge it leaves a burr on the bottom. Which if your trying to grind a radius catches on the rest and make it hard to turn the piece. With the ceramic disk there is no burr. It’s just a clean cut. Incredible. I’m not sure yet how long the disk will last compared to a normal one, but I have high hopes. 
Here are the tools I have ground so far. 



A left and right square tool, a knife tool, and a threading tool.


----------



## Iron-Iceberg




----------



## mikey

Wow, you did great! Not sure I could have done better myself, and I really mean that. Geometry looks good and those tools should work well for you. I really like your knife tool and the LH square tool - very nicely done, Sir! And yeah, I'm a ceramic fan, too.

I noticed a bit of light reflection at the tips of the turning tools - maybe hone them a bit more? Also, I cannot see a flat on the threading tool but that might just be the pic; if it is there then you should be good to go.

Have you tried cutting with them?


----------



## Iron-Iceberg

Thanks mikey, they're really sharp. Got a few slices on my fingers to prove it. Haha. One problem I’m having with the grinding wheel is that they are glued on and I cant change grits with out trashing the disk. So I picked a pretty aggressive disk for most work. This means that it takes a lot of work with the diamond cards to get the grinding marks out and get a good finish. One day I’ll get a belt grinder so that I can swap grits easier. 
The threading tool had a small flat on the end but I haven’t tried it out yet. I’ve mainly been using the LH square tool. That why it’s a little smaller as I’ve needed to regrind it a few times from dumb mistakes. 
I’ve saved a bunch of pages from this thread and need to go back and reread some of them on how to use the tools. I’m new to this so  I’m not sure what is going wrong when I’m not getting a good finish. Yesterday I was getting a really bad finish before I realized that the tool was floating  back and forth. It turned out the Gibbs where loose on the compound and I needed to tighten them up. I had cleaned  the compound when I got the lathe and adjusted them but they must have worked loose in use. 
I also had been practicing on some cheep hot rolled steel bar I had, just to get used to the machine and I don’t think it machines very good in the first place. 
I’m sure I’ll have more questions so thanks for the all help you have given here.


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## mcdanlj

@Iron-Iceberg those are nice clear pictures that show the shapes nicely!


----------



## mikey

Iron-Iceberg said:


> Thanks mikey, they're really sharp. Got a few slices on my fingers to prove it. Haha. One problem I’m having with the grinding wheel is that they are glued on and I cant change grits with out trashing the disk. So I picked a pretty aggressive disk for most work. This means that it takes a lot of work with the diamond cards to get the grinding marks out and get a good finish. One day I’ll get a belt grinder so that I can swap grits easier.



This is what I'm talking about. The circled areas reflect light and that tells you the intersection between the planes of the tool are not quite sharp. When they are, there is no light reflection at all:




I would hone them until that reflection is gone. Not only will the tool cut better but it will hold the edge longer. And yeah, I always get cut when honing my tools, too. 

I do agree with getting a belt sander someday. They are so much faster and easier to use, especially with ceramic belts.



Iron-Iceberg said:


> The threading tool had a small flat on the end but I haven’t tried it out yet. I’ve mainly been using the LH square tool. That why it’s a little smaller as I’ve needed to regrind it a few times from dumb mistakes.



That tool on the right end is your RH square tool and its my most used tool, too. I'm way past needing to grind another one; I've honed off my back rake! 

The flat on the tip of the threading tool is really important and not just from a thread form standpoint. That flat will keep the tip of the tool from cracking off; trust me. You kept it small enough so we can't see it in the pic; that should do fine.



Iron-Iceberg said:


> I’ve saved a bunch of pages from this thread and need to go back and reread some of them on how to use the tools. I’m new to this so  I’m not sure what is going wrong when I’m not getting a good finish. Yesterday I was getting a really bad finish before I realized that the tool was floating  back and forth. It turned out the Gibbs where loose on the compound and I needed to tighten them up. I had cleaned  the compound when I got the lathe and adjusted them but they must have worked loose in use.
> I also had been practicing on some cheep hot rolled steel bar I had, just to get used to the machine and I don’t think it machines very good in the first place.
> I’m sure I’ll have more questions so thanks for the all help you have given here.



If you're using steel from the hardware store then its probably 1018, which does not finish well with most tools. A Shear tool is supposed to do well with it but I have to make one and confirm it. 

Check to be sure the tool is on center height. This is more important than you might think. I don't mean eyeballing it using a center in the tailstock. I mean measure the center height of your lathe and make a height gauge that puts the tip of your tool dead on center. Some guys think this is not important but on a small lathe, it is. PM me if you're stuck for ideas on how to make a height gauge.

@Aukai asked a similar question about tool position and I've been waiting for Dave to respond. If he doesn't within a few days I'll have a go at it again. What it boils down to is understanding how the tool cuts and then playing with tool position until it does what you want it to. I've been doing it for so long that I don't even think about it or notice what my tool angle is anymore. Hang on, though. We WILL make it clear very soon.


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## tmenyc

Well, I finally got the knife tool done close to correctly, in HSS!  I watched Adam's (Machine Tech Video) videos last week, 2-3 times, and it finally clicked into place.  And it cuts well!  Not perfect, and the radius needs a bit of work, but i got over the hump. It was so much easier working with HSS than keystock, for me at any rate.  
Pictures below: HSS on left, keystock model right.





Now I want to cut the others , which I had no issues with, in HSS.
Thanks so very much for the help and patience.

Tim


----------



## mikey

Looks good, Tim. Let us know how your tools work for you.


----------



## Z2V

tmenyc said:


> It was so much easier working with HSS than keystock, for me at any rate.
> Pictures below: HSS on left, keystock model right.
> View attachment 289514
> View attachment 289515
> View attachment 289516
> View attachment 289517
> 
> Now I want to cut the others , which I had no issues with, in HSS.
> Thanks so very much for the help and patience.
> 
> Tim



Tim
Looks good. Glad to hear that it’s clicking for you. I have to agree with you on working the HSS compared to key stock. The key stock is so soft it’s easy to go too far when grinding, but it keeps you paying attention to what you are doing and it’s inexpensive. If you mess up, cut the end off and start over.


----------



## tmenyc

I'm finally getting a bit of time to grind the rest of my first set of HSS tool bits. Other than the fact that it takes longer and is more work cutting 3/8 than 1/4 (and I've now done both, and enjoy the process of grinding the 3/8 more, actually), what is the functional reason to choose one over the other?  My tool holders are AXA, so can handle either.  Seems to me that the actual cutting area is not that much larger on the 3/8, but there is more chip relief.  Is it width/height of the cut? Is cutting speed affected?  Once I really get the hang of turning soft steel, most of my work will be in acrylics, delrin, and ebonite with some smaller work in brass and bronze, although I will be having fun with steel and aluminum.  I haven't been able to find the reasons one chooses one or the other anywhere.  Guidance please?

Many thanks,
Tim


----------



## ttabbal

It's mostly rigidity. The thicker tool will deflect less. It won't matter on really light cuts, but it can be an issue. It's the same reason that you want to limit how much the tool or the work sticks out from the holder. I also have some 1/2" blanks for my AXA. They are about as thick as I can go and still center the tool. 

The smaller bits are nice to keep around as they are faster to make, cost less, and fit in tight spaces. I mostly use 3/8.


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## mickri

Holding the tool bits free hand and trying to keep them at the proper angle even with lines on the table doesn't work very well for me.   So I use my machinist square as a guide.  I found on my delta 1x42 belt sander that the edges of the table are basically square to the platen.  I drew a sketch of a 3/8" x 2" HSS tool bit and then added the angles based on Mikey's instructions way back on page 4 of this thread.  The side angle is 9.5 degrees and the front angle is 19.5 degrees.  I rounded those to 10 and 20 degrees respectively.  Easier to set the square.  To grind the side I set my machinist square to 80 degrees.  Here is the set up.




For the front I set the square to 70 degrees.




And for the rakes it is back to 80 degrees.




This works really well for me.  Thought that I would pass it on.


----------



## john.oliver35

I'm too clumsy when grinding, so I cut some pieces of plywood at various sharpening angles and use them to press against the tool.  The 30 degree one works great for threading tools!


----------



## mikey

You do what you gotta' do to make it work for you - glad you guys are sorting it out. I tend to just grind by eyeball. Having ground so many tools, I sort of know what each tool needs to look like. The shape of the tool is not too critical as long as it is strong enough and allows you to access the parts of the work you need to reach. What IS critical are the tool angles, the relief and rake angles. Those need to be understood and ground intentionally. That way, if the tool does not do what you want it to do then you can change it until it does. 

To be honest, I have sorted out the tool angles I need for most materials I turn. However, if I run into a material that doesn't cut as I think it should with a current tool that I'm using I have no reservation about changing the angles on the tool. If I think I need more side rake or back rake or whatever, I just grind it and see what that does. To me, that's the fun of being able to grind tools and it has taught me a great deal about how a tool cuts and how a lathe works. I hope the information found in this thread allows you to do the same.


----------



## mcdanlj

@mikey I finally got to grinding a RH square tool today, without reference to a model. I didn't bother buying keystock. After buying one of the lots of 100 3/8" HSS stock linked to earlier in the thread, I was too impatient to wait to try the real thing, and besides I had a project to do. I mostly freehanded the tool against the wheel with checks against a protractor. I don't have a radius gauge but I probably put about a 1/64 radius on it. I roughed the radius on a 120 wheel, and smoothed and honed it, and all edges, with diamond cards. Didn't get to the arkansas stone because I'm not sure where my honing oil is and my father taught me never to put metal to arkansas stone without oil. 

When I turned 6061 with the square tool, resonance was visible in the bright surface. Facing, while good, was not quite as beautiful, so I could stand to hone the side cutting edge some more.

(I've been playing with the idea of making parametric 3D models that people could set the angles they want and a scale factor, then 3d-print them out. I'd like to put that on thingiverse so that people can just adjust the angles in the thingiverse customizer, download, and print, but OpenSCAD doesn't have chamfer support I need to easily model the nose radius. So far it's just an idea.)


----------



## mikey

Congrats! Any chance we could see a pic of your tool and a pic of this resonance? A Square Tool should produce a near mirror finish on 6061 so I'm curious why you are not getting that.


----------



## mcdanlj

What I assume was resonance is a regular ripple in a near mirror finish on the turned surface. The "near mirror" quality is obscured by oil and grease now, and the parts are installed. No pictures handy right now.

I clearly have some roughness in my side edge. I pivoted the tool counterclockwise a few degrees and facing quality improved enough to see the reflection of the tool, though not quite as clear as I got from turning. I can't see the roughness in the side cutting edge, but I can sense it with my fingernail (unless I'm making things up), so I think that going back to the coarse diamond stone and working the edge some more should be my next step. That, and maybe ordering a loupe.


----------



## mikey

mcdanlj said:


> What I assume was resonance is a regular ripple in a near mirror finish on the turned surface. The "near mirror" quality is obscured by oil and grease now, and the parts are installed. No pictures handy right now.
> 
> I clearly have some roughness in my side edge. I pivoted the tool counterclockwise a few degrees and facing quality improved enough to see the reflection of the tool, though not quite as clear as I got from turning. I can't see the roughness in the side cutting edge, but I can sense it with my fingernail (unless I'm making things up), so I think that going back to the coarse diamond stone and working the edge some more should be my next step. That, and maybe ordering a loupe.



Look at the edge under a light source. If you see light reflecting off the edge then it needs work - one of the faces is not flat. From your description, it sounds like the tool is cutting almost okay. Sharpen it and it should work well for you.

Nice that you ground a useful tool!


----------



## mcdanlj

@mikey — Question about definitions: For the square tool, you say that all the angles are 15⁰. Except for the End Cutting Edge Angle, which you call out at 80⁰. However, all the references I find (including Machinery's Handbook) define the End Cutting Edge Angle relative to the tool axis. I think you are defining it relative to the Side Cutting Edge Angle instead? Then the End Cutting Edge Angle would be, by Machinery's Handbook's definitions, 25⁰, and you would hold the tip of the stock to the belt at a 25⁰ angle (on a 15⁰ table for the 15⁰ End Relief Angle). I'm referencing that not only because it's the major reference in the field, but also because the illustration of the angles there looks suspiciously similar to the illustration at the end of your "How to Grind a Turning Tool" document. The illustration is vague, not explicitly identifying the reference for the End Cutting Edge Angle, but the text seemed clear to me. Am I barking up the wrong tree here?

For my square tool, I had missed that one exception to your 15⁰ rule and used a 30⁰ End Cutting Edge Angle by MH's definition, for a 70⁰ included angle at the tip.

I don't want to get needlessly pedantic. However, I'm experimenting with my idea for a parametric 3D model, which requires precise definitions of each of the terms. ☺

At this point I figure that maybe specifying the included angle of the point would be clearer for the newcomer who is the target of the parametric model.


----------



## mcdanlj

OK, I have a model of the square tool — as cut against a wheel — mostly rendered:

https://github.com/johnsonm/lathe-tool-models/blob/master/square-tool.stl

I haven't figured out an accurate way to render the nose radius because I don't have a chamfer function in openscad that can follow an edge, especially a curved edge, but honestly if it's 3D-printed the plastic won't be a sharp edge anyway.

OpenSCAD source for this model is at https://github.com/johnsonm/lathe-tool-models/blob/master/square-tool.scad — and it's meant that you can plug in whatever angles you are interested in, and see what it would look like. I haven't uploaded it to thingiverse because it's not done and I'm not sure whether the customizer will work anyway because rendering the curves resulting from cutting it against the wheel is expensive.

I think it's not worth putting on thingiverse until I add the ability to model cutting it against a belt grinder and make it the default, which will make it much cheaper to render because it will avoid most of the rounded edges that are so expensive to render.


----------



## mikey

You are correct with regard to the end cutting edge angle. The books reference the tool axis so if you wish to define it that way in your model then that would be in line with the books and I would encourage you to do that.

Now, let me tell you why I define it the way I do. The many, many illustrations and discussions in the books have confused and confounded machinists and would-be machinists for decades. You can see the drawings and you can read the terminology used to describe each feature but translating that into actually grinding a tool from that information is not easy. You have multiple tool faces, each of which angles in two planes, and the angles change with the material the tool is used with. If you went to a trade school the instructor would tell about all of this but then he would show you how to actually grind the tool. The hobby guy doesn't have that advantage. He has the books. This has turned the majority of the hobby machinist population into a source of carbide insert tool buyers and users, largely because it is easier but also because that is the way the industry has gone so it has to be better, right? 

What I've tried to do in everything I've written on this subject is to simplify it as much as I could. I tried to define the what/where/why/how/how much for everything so that the average guy could grind a tool of his own, by himself, simply by reading what I wrote. And I used Mikey-logic to do it. 

For example, the side cutting edge angle and end cutting edge angle of the Square Tool is what it is because it is intended to allow you to access a shoulder. The shoulder itself is 90 degrees but an included angle of 90 degrees on a tool will rub so I made it less than 90 degrees so it wouldn't rub. I used the side cutting edge angle as a reference so I could tell the guys to make the included angle at the tip less than 90 degrees; the precise angle is not important. To grind that angle, the simplest way is to use the side cutting edge as a reference and draw a line that is less than 90 degrees to it and then grind to that line. Simple, easy to understand. I chose 80 degrees because it allows a 5 degree cushion between each edge that the eye can easily equalize in that corner when orienting the tool. Mikey-logic, you see?

I have taken other liberties beyond this angle thing. I have tried to explain what each angle does and how they can be modified to allow the tool to work better on a small lathe. That is a major departure from every reference text on tool grinding that I am aware of. I am probably the world's only proponent for small nose radii; every other resource and anecdotal opinion will tell you that bigger is better (but they don't tell you why).

I hope this clarifies this for you. Okay, okay, I went beyond clarity into diarrhea of the brain but it was important to explain that I had good reasons for going beyond the texts. 

At least now we have guys who can actually grind real lathe tools - good enough for me.


----------



## mikey

Aukai said:


> I know I have read it, but is there a single place to reference the differences in the angle of "attack" for the tool post for different processes for the different tools? Toward the head stock, 90*, toward the tail stock, different finishes, etc?



It's been some time since @Aukai asked this question and I finally found some time to respond to it.

"*How do I properly position a lathe tool*" is a really common question posed by new guys. I tried to cover this in post #107 of this thread but I guess it wasn’t clear so I’ll give it another go but with more detail. I will address turning tools only.

Here is a common illustration on positioning various lathe tools:




The old style tools used in this illustration were purpose-ground and each tool shape was meant to be used for a specific operation with the shank of the tool held perpendicular to the work piece. The value of the illustration is to show which part of the tool cuts for a given operation. For example, look at the picture for the RH facing tool.





See how the area just behind the nose radius is in contact but there is a gap further back along the cutting edge of the tool? The area of actual contact is usually only about 1/16” to 3/32” long, starting where the nose radius transitions to the side cutting edge. If you want to maximize the finish, use more edge but the amount shown is usually quite good.

Despite the fact that a modern general purpose tool is shaped a bit differently compared to the old style tools, the area of contact remains much the same as the old tools for a given operation. We simply turn the tool with our QCTP so that the contact area of our tool assumes a similar angle to the older style tools and we’re good to go. This is the short answer for how we position our tools and yes, it is that simple. The precise angle is not critical when using tools this way; your tool gives you a lot of leeway with regard to tool angles.

This is how you’re supposed to use your tools because it has proven to work for over a hundred years. Why fix it if it ain’t broke?

Of course, I don’t actually use my tools quite this way. Instead, I use my lead angle, edges, speed and depth of cut to minimize cutting forces to the extent I can. I do it this way because I prefer to use the geometry of the tool to make it do what it is supposed to do. I will tell you what I do and why, but this is for information only and does not constitute a recommendation.

First, let me tell you about edges. Every turning tool has three of them – the side cutting edge, the nose radius and the end cutting edge. The nose radius is a transition zone between the other two edges but it usually participates in the cut whenever one of those edges is in play. At any given time, you may be cutting with one, two or even three of these edges.

Second, any time an edge is in contact with the work you will generate cutting forces. For any given depth of cut, the more edge contact you have the greater the cutting forces will be so our goal is to minimize edge contact whenever we can.

Cutting force reduction is a big deal, and this is especially true on our smaller hobby class lathes. You may recall that I said before that the lead angle of the tool has an impact on cutting forces. The lead angle is the angle formed between the side cutting edge and a perpendicular line from the work piece.





When the shank of your tool is perpendicular to the work the lead angle is equal to the side cutting edge angle. For the sake of discussion, let’s call this perpendicular shank thing the *Standard Angle*.

Look at the point of contact in the illustration above. Using our standard angle as a baseline, turning the tool CW increases the amount of side cutting edge in contact with the work so for any given depth of cut, those forces will be higher relative to the standard angle. Conversely, turning the tool CCW, as in the middle of the picture, reduces edge contact and cutting forces decrease.

The benefit to turning our tool CW is that it improves the finish. The benefit of turning it CCW is that it reduces cutting forces, and a little bit goes a long way. So, how do we use this information?

Say we are using our Square Tool in the standard position to take a big cut and we encounter chatter. The lathe operator’s mantra for chatter is to “reduce our depth of cut or increase our feed” *OR* we can turn our tool CCW to reduce the lead angle. This reduces the amount of edge contact at the side cutting edge, which reduces cutting forces, and the chatter will usually resolve. Typically, very small changes in tool angle will be sufficient to resolve the chatter.

So, you must be thinking that if a little bit is good, wouldn’t more be even better? Yes, more can be better but the tradeoff is that the finish may suffer a bit. Quite often, when I need to take a big roughing cut, I will turn the side edge in a negative direction towards the chuck in almost a facing position to minimize cutting forces. How much can you turn? I turn it so most of the nose radius is engaged but none of the end cutting edge touches the work. In this position, the side cutting edge contact is as small as it can be for the depth of cut you’re taking. I try to start off with stock close to my finished size so big roughing cuts like this are usually not necessary but when you have a lot to take off, remember this one.




In addition to reducing the amount of edge contact by turning the tool CCW, you are engaging more and more of the side rake angle on top of your tool and you will see the path of chip egress change so that it comes off almost perpendicular to the side cutting edge. Given that side rake is the most influential tool angle insofar as cutting force reduction is concerned, you are essentially cutting with the least amount of force the tool is capable of in this roughing position.

So, unless I have to rough heavy, I usually rough with the tool in the standard position to maximize the finish when roughing. If the lathe strains or I encounter chatter I simply turn the tool CCW enough to eliminate it. If I have to rough really heavy then I go negative. If altering tool angle is not enough, I reduce my speed a little and increase feed a little and that tool will cut really heavy. Simple, right? This just uses everything you already know to enable your lathe to perform maximally.

This angle change thing works for both heavy roughing as well as turning into a shoulder, where your tool and side edge is essentially in a facing position. This puts the point of contact just aft of the nose radius and allows you to cut pretty heavy but also allows you to face out at the shoulder. Again, very simple and it works. Hope this makes sense.

So, how does this edge contact thing work for finishing cuts? If you recall, when you do not have a shoulder to contend with I recommend you turn the tool CW toward the tailstock to improve your finish. The contact patch is small, along the side cutting edge and part of the nose radius. Depths of cut are usually very small and I increase speed a bit to further reduce cutting forces (you do recall that increasing speed reduces cutting forces, right?). In this position, you are *shearing* with the side edge. More accurately, you are shearing with side rake. This thins and widens the chip and you will see the chip come off perpendicular to the side edge, indicating that side rake is the key angle in use. As you feed the tool towards the chuck you are essentially dragging the tool backwards and the chip direction can actually flow towards the tip of the tool. When this happens, watch the finish; it will be really good.

When we have to take sizing or finishing cuts into a shoulder, we can do the same thing except we will use the end edge instead of the side edge. To size, we turn the tool so the area on the end edge just aft of the nose radius contacts the work and we move into the shoulder and then face out. When finishing, we engage a tiny bit more of the end edge, increase speed, reduce our depth of cut and shear the work to size. Facing out in this position is done with the side cutting edge as usual. Ignore the finish in the picture; it is prop just to show tool position. In actual use, the tool is turned a bit more CCW than in this shot but you get the idea.




That’s basically how I turn on the lathe; sorry, nothing very mysterious. I use my edges and lead angle to manage cutting forces when roughing and I shear with the tool to size and finish. It does not take skill to do any of this, merely awareness of what you’re doing and why. I suspect that as you go along you will develop techniques of your own, which is how it should be. Hope this helps.


----------



## mcdanlj

mcdanlj said:


> OK, I have a model of the square tool — as cut against a wheel — mostly rendered:
> 
> ...
> 
> I think it's not worth putting on thingiverse until I add the ability to model cutting it against a belt grinder and make it the default...



I switched to modeling cutting the blank on a belt grinder. Makes it render orders of magnitude faster because there are so many fewer curves, so it should work fine on the thingiverse customizer inasmuch as anything does, and that will make it easy to explore any reasonable angles and see what it would look like. Take a look: https://www.thingiverse.com/thing:3560037

I have modeled the square, knife, and threading tools following the "Making HSS tooling for the lathe" document to the best of my ability.

I still haven't modeled nose radius; to do that I'll need to spend some time with pencil and paper to make sure I get the trig right (it's easy to miss a triangle and wonder why it's _almost_ right). Again, with @mikey's small recommended nose radii it's not worth it for printing a blank when you are typically spitting plastic out of a 0.4mm nozzle. If I do model it, I'll model it only for grinding against a belt, not a wheel. I also didn't model the tip of the threading tool for the same lack-of-resolution reason.

I decided to model the tools together in a single file with mostly shared code between the models, which means that I renamed the files. The new source is at https://github.com/johnsonm/lathe-tool-models/blob/master/mikey.scad

If you look at the model at https://github.com/johnsonm/lathe-tool-models/blob/master/mikey.stl you'll be able to rotate the model on your screen, zoom in and out, etc. @mikey, take a look and see what you think! ☺


----------



## mikey

Pretty cool there, @mcdanlj! The geometry looks great. Will folks be able to 3-D print these things from your files?

You did some great work on these. I hope they help someone.


----------



## mcdanlj

mikey said:


> Pretty cool there, @mcdanlj! The geometry looks great. Will folks be able to 3-D print these things from your files?
> 
> You did some great work on these. I hope they help someone.



Thanks — especially for making sure the geometry looks right.

Yes, folks can download the file mikey.stl (either from github where it will always be up-to-date with any new changes I make, or thingiverse where I might or might not remember to update it) and print the standard tools. The slicing programs that prepare the models for printing will allow them to break them apart and print less than the whole set of three.

Folks also can download mikey.scad and modify it in OpenSCAD to print variations. For example, changing to the following settings will (if I understood correctly) create a model of your suggested aluminum tool in place of the default square tool:



		C-like:
	

back_rake_angle = 40;
side_rake_angle = 18;


I'll say that it's one thing to see "40⁰ back rake" written in a description, and another to see what that really means:




That makes me wonder whether I should add a parameter for how deep the back rake is. Would you cut it that deep, or would you cut it less deep?




I could add a parameter for the relative depth of the back rake, especially if it would be useful! I'd be interested in your thoughts there. ☺ [Edit: back_rake_depth_ratio added for this purpose.]

Additionally, they can choose which tools to work on, and they can see how I modeled it. I modeled it by modeling the actual grinding operations, and those already skilled in OpenSCAD can follow the code and see what the positioning looks like, either with a platen or a wheel.

Folks can also open the mikey.scad file in the thingiverse customizer and modify the settings there, instead of downloading OpenSCAD. After modifying them there, the customizer will provide a set of three tools just like the STL that I built and uploaded there. Note that I've found the customizer to be occasionally non-functional; I added that hoping that it might work but didn't want to depend on it.

Folks can also send the STLs to shapeways to order prints. You can print in a selective laser sintered 60% steel 40% bronze mixture that might allow you to polish the edges, though it would be even less useful for actual cutting than keystock would be! But it should be a closer model than layers of extruded plastic, so would be an option more similar to your models, for folks who just want to keep them around for reference.

Update: Before I uploaded the new version of mikey.scad with the back rake depth ratio added, there were 350 downloads of the old version, as well as 344 downloads of the STL, in less than 18 hours. Apparently I underestimated the level of interest in this model!


----------



## mcdanlj

I substantially improved the summary documentation on GitHub and thingiverse to show how to use the models.


----------



## mikey

mcdanlj said:


> I substantially improved the summary documentation on GitHub and thingiverse to show how to use the models.



Pretty cool, pretty cool! I am totally out of my league with this 3-D printing thing but I can see the utility of it. 

I wonder if this will bring more members to the HM site. If so, then we'll have you to thank for that, madanlj! 

I started this whole model tools thing with my deceased best friend in mind. I'm going to see him at the graveyard tomorrow and I'll tell him what we started here. I think it will make him happy to know we helped some folks along.


----------



## Aukai

Mikey, thank you very much for the lead angle information, still digesting it. Most helpful, and give our respects too...


----------



## mikey

Try not to over think it. Chuck up a piece of stock and play with this. It will become clear very quickly.


----------



## mcdanlj

mikey said:


> I am totally out of my league with this 3-D printing thing but I can see the utility of it.



While I had interest in machining from a young age, 3D printing was my "gateway drug" to actually getting started.

I have updated the models again, this time including a 3D model that is *not* intended to be printable but can be explored on a computer, showing what it looks like when each of the tools is held up to the platen of the belt grinder. You can use the "Thingiview" on mikey-cutting-demo.stl in thingiverse, or play with it on github.

I still haven't modeled the nose radius. That will take some careful drawings to get the trig right.


----------



## mcdanlj

mcdanlj said:


> this time including a 3D model that is *not* intended to be printable but can be explored on a computer,



I'm sure glad I did that, because exploring it, I realized that my previous models had failed to model Side Rake Angle (SR). I just added SR to the models and pushed new OpenSCAD code and resulting STL files to github and thingiverse.

I think that I need to print these out and measure the angles to make sure I get them right. Maybe even mail a set to Hawaii for master validation!


----------



## mikey

That is so cool! You can pan and see how the tool has to contact the platen. That should help someone visualize how it has to be ground. Great job!!!


----------



## Aukai

I like it, but a fella could get dizzy....


----------



## mcdanlj

You can see how the imprecision of 3D printing made me interested in machining... And, @mikey , you'll be able to tell even more when they arrive. I added the stainless steel and aluminum tools that you described earlier in the thread. And frankly if you'd like to see more, let me know, because, well, there's lots of flat-rate shipping room in that box and the plastic is cheap.

Sitting on the box they will travel in to Hawaii:
















And here they are before they were finished:


----------



## mikey

Awesome, macdanlj! 

About 8-9 years ago, my son told me about 3-D printing and I questioned if it was really a thing. Back then it was all DIY and it made me wonder how the field would advance. Now you can do this! The one regret I'll have when I die is that I'll miss all the cool stuff that has yet to be thought of.


----------



## mcdanlj

There's a lot of DIY left in 3D printing. It's still where a lot of the advances come from. (My other main forum right now, Maker Forums, is where a bunch of 3D printing innovators ended up after Google pulled the plug on Google+; there were a lot of 3D printer aficionados there.) The way the "gateway drug" aspect worked for me was preparing to machine parts to rebuild a poor-quality 3D printer into a custom build... And, well, I got distracted by the machines and I haven't quite finished that rebuild, because I keep spending my time on the shop instead of finishing the rebuild.

Those are relatively low-quality prints, made on a cheap printer from a few years ago. The printer is similar in quality to what you can get today for $200. I almost feel bad to even send them to you as a waste of time, but it will be totally worth it either if you determine that the angles are right (or close; plastic can shrink non-linearly when it's printed), or if they are wrong in a way that highlights another mistake in my model.

There's a jog on the lower back side cut of the stainless tool that makes me worry that I might have a mistake in the trickiest bit of trig in the model:

(scea*sra*era*br == 0) ? wheel_t : ((-pivot_offset(scea=scea, sear=sear))+(tan(sra)*stock_w)+(tan(era)*stock_w)+(tan(br)*stock_w)/sin(scea) + wheel_e_r*4) * 2;

I swear I drew it all out on paper and it made sense there, but it it's actually correct the stainless tool should have a smooth cut all the way back. On the other hand, if the angles are all correct, then it's probably not worth tracking down.

Would an aluminum tool really have such a long thin nose as you see on that model? Do you have pictures of the aluminum cutting tool as described early in this thread, with 40⁰ back rake, 18⁰ side rake, 15⁰ relief side and end relief angles? You say "I have a tool ground exactly like this, with the same reasoning, and it will easily take a 0.25” deep cut on my 11” lathe." — I'd love to make sure I understand the shape so that I get the model right.

Thanks!


----------



## mikey

I've got a lot going on around here right now but I'll try to get some pics when I can. I'll also be sure to feed back to you on the tool angles and geometry. I understand that you need to get the angles right so other folks can use them but for YOU, I hope you understand that the angles themselves are not nearly as important as knowing why they are what they are and what they allow the tool to do for you.


----------



## mcdanlj

Exactly. The first goal of the models is to communicate accurately about the starting point from which to learn, just like the physical models.

The physical models are better for communicating those precise starting shapes you defined, optimized for our (typically) hobby needs.

The digital models are better for understanding what other sets of angles look like by comparison. Unlike a drawing, they can be panned and zoomed to get a better 3D sense of any arbitrary set of angles, including any set you might pull out of, say, machinery's handbook.

In any case, the purpose is to learn how to manipulate the angles toward a purpose. That's why I want to validate that the digital models don't lead people astray regarding what the angles mean in practice, so their starting point is right, and they can communicate accurately with others what they have learned.


----------



## mikey

Got it.


----------



## tmenyc

Mikey and others,
I discovered that the point on this tool has gotten damaged.  How do I repair this, just regrind the front, top, and side planes asuttle as possible to take off the broken lead edge?
Best,
Tim


----------



## mikey

I would re-grind all three faces, then hone well. In your tool, there is light reflecting off the intersection between the side and top faces. The intersection between the top and end face is huge so this tool will not cut well. I suggest you regrind it and hone it so no light reflects off of any intersection between angles.


----------



## tmenyc

Thanks, Mikey.


----------



## mikey

Tim, I took a closer look at your tool. It looks like you're using a wheel to grind with, which is fine. When you regrind it, try to get the top and bottom of the tool face even on the wheel. There will be a dip in the center of the face due to the radius of the wheel but try to make even contact at the top and bottom of each face. Same thing when you hone it; try to get evenly honed areas at the top and bottom of each face. Whenever two faces intersect, you should not see any light reflecting off that edge when the tool is sharp. On a knife tool like this, keep the nose radius really small but round and even from the top to the bottom of the tool.  The overall shape of the tool is good, though, so hang in there.


----------



## tmenyc

Shall do!


----------



## mcdanlj

mikey said:


> keep the nose radius really small but round and even from the top to the bottom of the tool



I decided to try to add the nose radius to my 3D model to show what it should look like. "How hard could it be? Just cut off the end of the nose and merge in a cylinder with the nose radius and bob's your uncle!"

When I did that, the cylinder intended to represent the nose radius was very much in the wrong place. Off by several degrees, and off by more with more aggressive relief angles. I realized that the angles are compound and, for example, if you set the table angle to 15⁰ for side relief angle, and then hold the tool to the belt at a 15⁰ angle on the top for a 15⁰ side cutting edge angle, you'll get a 15⁰ side cutting edge angle but have _a bit more_ than 15⁰ side relief angle.

_This isn't enough to matter when you are grinding these tools!_ At the angles @mikey talks about, you'll generally be within about a degree, and remember that @mikey's recommendations are based on these simple table angles and tool angles, not on trig functions and compound miter math, so _do it the easy way_ to replicate his starting points, and then when you are adjusting based on your machine, your stock, your desired finish, etc, you'll be adjusting by at most a few degrees at a time, and the change you are actually making to the underlying angles is all you care about, so it still doesn't matter.

It does matter when you're trying to make a precise computer model (as I am), and it does matter if your goal is to replicate precise angles from published works, *if and only if* the angles in use are sufficiently large. And, it turns out, one of the specific clear points from @mikey's research was that hobbyists might prefer larger angles than are typically published for commercial work. But if you are trying to precisely replicate some industry-specified model that has, say, a 25⁰ side cutting edge angle and a 20⁰ side relief model, you'll have to set your table at 18⁰ rather than 20⁰ in order to get 20⁰ of side relief, because _asin(sin(25)*cos(20)) ~= 18_. The same kind of adjustment would apply to large end cutting edge angle and end relief, of course.

This is not generally important, and if laying out piles of right triangles in three dimensions and muttering SOH-CAH-TOA over and over doesn't sound fun, you should ignore the whole thing, On the other hand, if you enjoy piling up trig functions through three dimensions and keeping track of multiple reference frames while doing so, let me know and maybe you can find the bug in my model that is breaking my ability to consistently 3d-model the nose radius.


----------



## mikey

And I thought tip geometry was complicated! I had the easy part, figuring out how the geometry works and how to grind it to do what I wanted it to do. If I had to sort it out with Trig I would have gone to inserted carbide tools and stayed with them! Kudos to you for doing this, @mcdanlj!!


----------



## TonyBen

I'm almost done grinding my first tool on a 1/2" HSS steel blank. I used Adam's video and I'm making a square RH turning tool since the majority of what I'll be doing is trimming barrel shoulders and making square cuts. I just need to do the top angles, round the nose and hone the surfaces. I'll post pics later.

I went out and bought a Porter Cable bench sander with the vertical sanding belt and the round sanding wheel. I've been using the round sanding wheel and the angle guide that came with the sander. I also bought an angle finder and found the angle guide on the tool to be 1˚ off.

I'll have to set up the bench grinder to make the last two top cuts.

I've got two 3/8" blanks I can work with also.

Tony.


----------



## mikey

Please keep us posted on how your tool turns out and how it works for you, Tony.


----------



## TonyBen

Here's my first attempt. Will try to finish the top cuts today. The  bench sander came with 80 grit. I bought a finer belt for finishing later.





















Tony


----------



## mikey

Looks good so far, Tony. At some point, see if you can find some ceramic belts for that machine. They grind much faster and cooler than aluminum oxide. Also pick up some stick wax to lube the cut. This extends the life of the belt, reduces friction and has many other uses in the shop.


----------



## TonyBen

All done. I did add a nose radius using some 240 grit sandpaper on a flat granite stone after I snapped these images last night. I had to use my 6" bench grinder to do the top cut as I couldn't get the compound angle right on the disk sander











I did a facing cut on front of my 3-jaw backplate last night with this tool to try and bring the runout down and it went from 0.013" to 0.010" on a 1" steel shaft. 

I hate facing cast iron as theres just so much fine dust.

Looks like I'll be installing the 4-jaw and turning an aluminum bar with this tool (I don't have a large steel bar right now), then I'll clamp the 3-jaw to the bar and face the back of the 3-jaw backplate where it would contact the spindle shoulder and try again. 

This tool should work real well for shoulder turning. Now I just have to figure out what to do with the other side. I might make a left hand knife tool since there are times that I have to turn down a boss for a gas cylinder or an operating rod guide and I have to chuck up the barrel the opposite direction and cut from the other side.

I have two more 3/8" blanks and I will make a threading tool as well as a boring bar. I do need to make custom muzzle guides for odd size flash suppressors and muzzle brakes that keep me from using my cleaning rods from the muzzle end. I'll have to buy some delrin to work with which I've never cut before on a lathe (or a mill for that matter).

Tony.


----------



## mikey

Came out well, Tony. Its a totally different experience grinding on a belt sander vs a bench grinder.

May I suggest you buy your boring bar instead of grinding one from your tool blank? If you don't do a lot of boring then I suggest you buy a solid carbide bar from Micro 100. They can be found on ebay if you're lucky or on Amazon. I don't feel that it is worth the time and effort to grind boring bars from square bits because your bore depth capacity is only about 4 times the smallest diameter of the bar; a solid carbide bar will go twice the depth easily. 

When you grind your threading tool, be very, very fussy about the 60 degree angle. It has to be precise. I assume you have a fishtail gauge, right? If so, confirm the angles under magnification and don't forget to put a tiny flat at the tip to prevent it from cracking off. Hone it until it is razor sharp and it will cut threads way better than an inserted carbide tool will. 

Keep at it. You're off to a very good start!


----------



## tmenyc

Tony, 
Mikey got me on the Micro100 boring bars, since I have a need for a very small one.  Download their catalog and happy reading; it's fascinating.  IIRC the regular boring bars were the first section.  Then, buy from KBC Tools.  When I found it on Amazon their delivery date was months into the future; I think KBC has the Amazon relationship so they have it, but don't actually stock it.  I got it from KBC in a couple of days.  My little boring bar is an incredibly elegant piece of carbide, beautifully tooled.  
Tim


----------



## TonyBen

Used my knife bit to make a pillar for a rear action screw. I still need to add more radius to the nose. I used a long steel female standoff and drilled the center to 1/4" with the tailstock.







I then cut a section off and faced the ends to length and glued the pillar into the stock





Here's how a 1/4"x28 screw will sit inside...





The knife tool is working well and I used it to face some other parts I had to cut to length as well.

Tony.


----------



## mikey

Yeah, the knife tool does not work that well for general turning but it works pretty good for facing cuts or with very light turning cuts. Glad its working for you, Tony.


----------



## TonyBen

Yeah, I can get three to five pillars from that single standoff. I think I’ve got four of them. 

You probably can’t see it from that camera angle but I have the tool angled maybe 10 or 15 degrees pointed back toward the tailstock. It was cutting pretty nice with that angle. 

Tony.


----------



## Bamban

TonyBen said:


> You probably can’t see it from that camera angle but I have the tool angled maybe 10 or 15 degrees pointed back toward the tailstock. It was cutting pretty nice with that angle.
> 
> Tony.



Tony,

The scheme you mentioned (I learned from Mikey) works very well even on indexable carbide inserts. 


nez


----------



## mickri

I need to make more tool holders for my Norman style QCTP but didn't know many I should make.  So I decided to go through this entire thread and make a list of the different types of tool bits. Here is the list of the basic tool bits and some not so basic that are discussed in this thread.  Included is the page/post # so you can easily find them.

Right hand turning.  Page 4 Post 102
Left hand turning.  Page 4 Post 102, Page 5 Post 129
Knife tool.  Page 4 Post 102,  Page 5 Post 135
Threading tool.  Page 4 Post 102, Page 5 Post 136
Fly cutting tool. Page 5 Post 141
Honing tool bits Page 7 Post 193
Sheer tool.  Page 11 Post 324. Page 12 Post 338
Round nose tool.  Page 15  Post 435


----------



## Z2V

Thanks for that!


----------



## Tombstone

I been gone for an long time. I hate get back reading


----------



## WCraig

So, I'm still a rookie...what HSS tool do you guys use for chamfers?  I see Youtube videos all the time where they use the edge of a diamond-shaped carbide tool.  I'm not sure I've ever seen a video where they cut a chamfer with a HSS tool.

Craig


----------



## ttabbal

WCraig said:


> So, I'm still a rookie...what HSS tool do you guys use for chamfers?  I see Youtube videos all the time where they use the edge of a diamond-shaped carbide tool.  I'm not sure I've ever seen a video where they cut a chamfer with a HSS tool.
> 
> Craig




I do it all the time. Much the same way, I use the side of whatever tool is on the lathe, usually a square tool. Rotate the QCTP to whatever angle looks good and has clearance, then bring it over to the work.


----------



## Downunder Bob

I have seen HSS tools ground in many different ways, just about every machinist has his/her preferred way of shaping the tool. You can grind a HSS tool just about any way you like as long as it has side and front clearance and a bit of top rake mount it on center and it will cut. 

One advantage of HSS over carbide is you can make your own profile tools  Consider a thread cutting tool is a profile tool. I have seen complex shapes ground into a HSS tool so that the shape can be reproduced in a single plunge cut, Although you have to careful about chatter and not to overload small machines.


----------



## tmenyc

mikey said:


> If you want a tool specifically for Delrin, make one with these angles. Like most tools, a few degrees of change can make a big difference and this tool works. Use cobalt, keep it sharp and it will take a huge cut without even slowing down.


Mike, going back to p. 15 #436, you give the measurements to use for a plastic-dedicated tool, and recommend cobalt.  Which brand or type do you recommend to use?  
Many thanks,
Tim


----------



## mikey

ttabbal said:


> I do it all the time. Much the same way, I use the side of whatever tool is on the lathe, usually a square tool. Rotate the QCTP to whatever angle looks good and has clearance, then bring it over to the work.



I do this, too. I think the knife tool works better for chamfers but if I have a square tool in the post at the time, that is what I use. I don't own a dedicated chamfer tool.


----------



## mikey

tmenyc said:


> Mike, going back to p. 15 #436, you give the measurements to use for a plastic-dedicated tool, and recommend cobalt.  Which brand or type do you recommend to use?
> Many thanks,
> Tim



Unless you're doing a lot of work with Delrin, simple M2 HSS will do. Delrin can be abrasive so cobalt is a good idea if you work with that material a lot - holds an edge longer. I think any 5% cobalt bit you have on hand will work fine.


----------



## Mike6158

It's too late to read this whole thread but this looks like gold


----------



## mikey

??? Why is it too late, Mike?


----------



## Z2V

Yep, it’s a great read!


----------



## Mike6158

mikey said:


> ??? Why is it too late, Mike?



Bad wording. It's 10:30pm here. Too late in the evening.


----------



## mikey

Oh, okay. Jump in when you can and join us. The guys and I will help you out if you need it.


----------



## Mike6158

Will do, I needed a form tool to cut a small pulley out of bronze round stock. .004 tip for the flat part at the bottom and 79° on each side. I winged it and got it done. They weren't critical parts but the right tool, a better lathe, and a lot more skill on my part, would have made it go quicker.


----------



## WCraig

Mike6158 said:


> It's too late to read this whole thread but this looks like gold



The above post can take you to the discussion of specific tools:

           #1,007          

Craig


----------



## tweinke

And to think this thread is still going!


----------



## ttabbal

One of the most informative threads on any forum I've ever seen. It deserves it.


----------



## Downunder Bob

tweinke said:


> And to think this thread is still going!



And so it should be, tool grinding is probably the single most important skill in our field. after 58 years in the trade I'm still learning, and relearning things I had forgotten. 

There is of course always more than one way to skin a cat. This is also true of tool grinding, while clearance angles and rakes are important in a general sense any tool that does the job is a good tool. 

What I'm trying to say there is not really a single right way to do it. If we have a tool that works, even when others might say it's wrong, how can that be if it works?

I hope this thread continues.


----------



## mikey

I agree with all of you and especially you, Bob ... if a tool works for you then that is what matters. 

As I think back, the initial and primary goal was to help you guys learn to grind tools that were known to work well. We chose tools that enabled us to do the three key turning operations - turning, facing and threading - and we learned what defined their functions and what the angles on each tool did. We learned about cutting forces and how each angle on the tool affected those forces and very importantly, the role of the nose radius and its relationship to deflection and therefore ... accuracy. We went through the thought process for altering those tool angles so that one day you will know how to alter them to meet your specific needs. Heck, we even went through how to use these tools and I hope that helped. The one thing we didn't cover was boring tools so I wrote a separate thing to handle that. Hopefully, that covers all the basic lathe operations except cutting threads.

Most importantly, at least to me, was the unexpected result of all of us getting to know each other a little better. I have a much deeper appreciation for all of you. I have also been totally amazed at how quickly you guys have picked this up.

Jeff in particular has been amazingly supportive. You guys don't know this but we lost the original three sets of model tools. I didn't find out about it until later, when Jeff admitted that he was grinding replacement sets and sending those models out on his dime. He did this quietly, without expecting anything from anyone. I believe this is Jeff's way of helping all of us learn to grind tools that will help us grow as hobby machinists and I am so grateful to him. We all owe Jeff major props for being the awesome guy that he is! Thank you, Jeff!!!

To all of you who made this thread what it is, thank you! To all of you who join us in the future, welcome and don't be afraid to ask questions. These guys now know enough to guide you even if I am not here. 

If you take anything away from this thread, take this: Always ask why things are the way they are and then question if that thing can be done better. How does it work and what would happen if you change this or that? Understanding the what is not enough; you have to know why, how, and how much. Then don't guess; test it. Whatever you do, please don't accept that things are what they are because its always been done that way. Instead, question it and in the process, grow.

And no, I have not forgotten about the shear tool I promised to grind. I just have a great deal on my plate and don't have the mindset to handle that tool right now, but I did not forget.


----------



## Downunder Bob

mikey said:


> I agree with all of you and especially you, Bob ... if a tool works for you then that is what matters.
> 
> As I think back, the initial and primary goal was to help you guys learn to grind tools that were known to work well. We chose tools that enabled us to do the three key turning operations - turning, facing and threading - and we learned what defined their functions and what the angles on each tool did. We learned about cutting forces and how each angle on the tool affected those forces and very importantly, the role of the nose radius and its relationship to deflection and therefore ... accuracy. We went through the thought process for altering those tool angles so that one day you will know how to alter them to meet your specific needs. Heck, we even went through how to use these tools and I hope that helped. The one thing we didn't cover was boring tools so I wrote a separate thing to handle that. Hopefully, that covers all the basic lathe operations except cutting threads.
> 
> Most importantly, at least to me, was the unexpected result of all of us getting to know each other a little better. I have a much deeper appreciation for all of you. I have also been totally amazed at how quickly you guys have picked this up.
> 
> Jeff in particular has been amazingly supportive. You guys don't know this but we lost the original three sets of model tools. I didn't find out about it until later, when Jeff admitted that he was grinding replacement sets and sending those models out on his dime. He did this quietly, without expecting anything from anyone. I believe this is Jeff's way of helping all of us learn to grind tools that will help us grow as hobby machinists and I am so grateful to him. We all owe Jeff major props for being the awesome guy that he is! Thank you, Jeff!!!
> 
> To all of you who made this thread what it is, thank you! To all of you who join us in the future, welcome and don't be afraid to ask questions. These guys now know enough to guide you even if I am not here.
> 
> If you take anything away from this thread, take this: Always ask why things are the way they are and then question if that thing can be done better. How does it work and what would happen if you change this or that? Understanding the what is not enough; you have to know why, how, and how much. Then don't guess; test it. Whatever you do, please don't accept that things are what they are because its always been done that way. Instead, question it and in the process, grow.
> 
> And no, I have not forgotten about the shear tool I promised to grind. I just have a great deal on my plate and don't have the mindset to handle that tool right now, but I did not forget.




Absolutely Mike. My favorite dislike is "we've always done it this way" That is a guaranteed way to stop progress. look, learn and question, not in argumentative way, but simply ask why do we do it that way, and if you have  a thought "why not this way" let's hear it If it has merit we'll explore it, if not we'll explain why. No one here will laugh at you for having an idea. Without ideas, we as a species would still be living in caves and throwing rocks at other animals when we were hungry.

Have a look at the different threads and follow the guys who post their progress, some of these were never formally trained in the dark arts of metal machining, but are completely self taught, From them we are learning that the established way is not the only way.


----------



## ttabbal

Very cool Jeff! If you need another set, let me know. I'll ship a set or two to out. The models only take a few minutes to grind up.


----------



## thomas s

Again thank you Mikey, Jeff and everyone that helped out. This has been the best thread ever on this forum.


----------



## Z2V

Mikey,  thanks for the kind words and all the hard work that you put forth to make this thread the success that it is.


----------



## Mike6158

I just got to page 5 and I already had a few revelations-

(1) I'm in good company as far as lathe size goes. Mikey's running a Sherline (slightly jealous) and a lot of people on the thread are small lathe guys. I'm glad I found this place over a year ago.
(2) A belt grinder has been on the "I want that" list for a while. Now to find a good one...
(3) Ceramic belts? Interesting. Speaking of cutting, I just tried a Freud Diablo Laminate / non-Ferrous blade on an aluminum electronic enclosure. I needed to cut it in half. It was double the size I needed so I got 2 for one and the project takes up 3" less space. The cut? Wow! I barely had to file it. The burr was almost nil. And it cut thru it like butter. 
(4) I'm interested, where do I sign up? I could have used this skill


----------



## mikey

Most hobby guys run smaller lathes so these HSS tools are well suited to them. I also own an Emco Super 11 CD. It, too, is on the small side but is pretty decent and works very well with HSS tooling.

I have that Freud blade and agree - works good on aluminum and plexiglass. 

PM Jeff to get on the list for the models, Mike.


----------



## Aaron_W

Mike6158 said:


> I just got to page 5 and I already had a few revelations-
> 
> (1) I'm in good company as far as lathe size goes. Mikey's running a Sherline (slightly jealous) and a lot of people on the thread are small lathe guys. I'm glad I found this place over a year ago.
> (2) A belt grinder has been on the "I want that" list for a while. Now to find a good one...
> (3) Ceramic belts? Interesting. Speaking of cutting, I just tried a Freud Diablo Laminate / non-Ferrous blade on an aluminum electronic enclosure. I needed to cut it in half. It was double the size I needed so I got 2 for one and the project takes up 3" less space. The cut? Wow! I barely had to file it. The burr was almost nil. And it cut thru it like butter.
> (4) I'm interested, where do I sign up? I could have used this skill




If I had to guess, based on the active posters the 10-12" class is probably the most common on this site. I think that there are probably a lot more out there with mini-lathes, but guys are funny and they tend not to want to talk about their little equipment.    Many of the posters with big lathes started off with smaller lathes.

Much better than most other sites, but there is still a bit of a bias against the mini-machines. I think many mini-machine owners stick to brand specific forums and facebook groups after having bad online experiences which is too bad. Most of the little machines are great within their capability and are much less intimidating for somebody testing the waters of machining as a hobby. 
That said this site does have many great ambassadors for this hobby who don't judge people on the size of their machine, only what they do with it.


I use a Diablo non-ferrous blade on a 7-1/4" Ryobi miter saw, it does a nice job on brass and aluminum. I've use Nikx-Stikx on the blade to keep the aluminum from sticking and so far so good.


----------



## Mike6158

I wouldn't mind having a 10" - 12" class lathe but it won't fit in the kitchen  I neeeeeed to build a shop. I want a lathe and a good mill. Shop first.

The little lathe will work pretty well on small stuff. If I can learn to measure and machine that accurately the rest should come in time.

I converted my cutoff saw just to get my parts cut. The blade was a little too thin for the saw and I had to shim it. The blade is back in it's package now. I'll probably get a dedicated saw for it. I didn't see a smaller blade so I ended up with a 12" blade (trying to make up for my lathe size). Nikx-Stikx... I hadn't seen those before.


----------



## Aaron_W

Mike6158 said:


> I wouldn't mind having a 10" - 12" class lathe but it won't fit in the kitchen  I neeeeeed to build a shop. I want a lathe and a good mill. Shop first.
> 
> The little lathe will work pretty well on small stuff. If I can learn to measure and machine that accurately the rest should come in time.
> 
> I converted my cutoff saw just to get my parts cut. The blade was a little too thin for the saw and I had to shim it. The blade is back in it's package now. I'll probably get a dedicated saw for it. I didn't see a smaller blade so I ended up with a 12" blade (trying to make up for my lathe size). Nikx-Stikx... I hadn't seen those before.



I started a couple years ago with the Sherline lathe in a spare bedroom / hobby room, then moved down into into the basement when I got a Sherline mill, because mills are messy. I only got larger machines earlier this year (and they are still relatively small) and am still in the process of turning a corner of the basement into a small shop. Although joined by bigger machines the Sherlines are still employed and I have no intention of booting them out into the cold. It can be handy to have an extra machine around and small ones don't take up a lot of space.


----------



## tmenyc

Mikey and everyone, 
It's time for me to report in...RH and LH square, RH knife, 60 deg threading tools made from this post and a lot of help from Mikey on the side.  I'm using a 6" Dewalt bench grinder so they're not as pretty as those done on a belt grinder, but so far the square and threading tools are working pretty well!  I think I need to broaden the NR on the knife tool though.    Coming up are a couple of tools for brass and aluminum and an offset threading tool. And, I dug up an old Carboloy tool in the tools that came with the lathe, want to sharpen that up and give it a shot. 
I've gotten really interested in doing this, since the HSS tools are perfect for my old lathe.  It's a huge mental and skill challenge, and I've enjoyed every minute of it.  All suggestions, comments solicited!  
Thanks again, Mikey, I'm nowhere near done but couldn't have gotten this far without your encouragement. 
Tim


----------



## mikey

Definitely getting better, Tim! 

Yeah, it does take some time but this is a skill that will last you a lifetime so it's worth learning. I think you're doing great!!


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## DavidR8

Okay folks I’m onboard this thread. I’m waaaaay behind on reading up but I’ve PMed Z2V to be included. 


Sent from my iPhone using Tapatalk


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## Aaron_W

Somewhere in the 35 pages of discussion was a tip on using a protractor and thin permanent marker to mark the desired angles right onto the tool blank being formed. Since I don't have a fancy guide (yet, it is on my ever lengthening project list) just the standard grinding platform I have found that to be really helpful to keep my grinding on the proper angle.


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## tmenyc

DavidR8 said:


> I’m waaaaay behind on reading up but I’ve PMed Z2V to be included.


It's a marathon,  not a sprint....


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## mikey

I just finished restoring a Sherline lathe and the owner used it for the very first time today. I let him try my old square tool that needs regrinding; must be at least 10-12 years old and has lost most of its back rake to honing. He was cutting 12L14 and it blew his mind when he took a 0.050" depth of cut (0.100" off the diameter) at 1200 rpm; cut like butter! Pretty sure we could have gone much deeper but he wanted to try lighter cuts. Then he took off a thou, and then he interpolated and took a 0.0001" depth of cut to produce a steel wool ball made of angel hair that just about floated into the trash bin. He is now convinced that the right tool really does make a difference.

I've said it before. A good tool will take as big a cut as your lathe can handle, then turn around and take a micro cut to bring you in dead on size without you even noticing it. Trust me, guys; this tool grinding thing is a skill well worth learning!


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## Downunder Bob

Yes Mikey I agree, the skill of hand grinding lathe tools and drill bits Is probably the most important skill any machinist can learn

I does't matter how well you learn the many other skills required, without the ability to grind good cutting tools the rest is all but lost.


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## DavidR8

I've probably missed it somewhere along the line. What's the preferred belt for grinding bits?


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## ddickey

Ceramic





						2 X 72 Inch Coarse Grit Premium Knife Makers Ceramic Sanding Belts, 6 Pack Assortment: Amazon.com: Industrial & Scientific
					

2 X 72 Inch Coarse Grit Premium Knife Makers Ceramic Sanding Belts, 6 Pack Assortment: Amazon.com: Industrial & Scientific



					www.amazon.com


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## Z2V

Same here. Orange ceramic


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## Downunder Bob

we never used belts, only 60 or 80 grit aluminium oxide wheels, Usually 6"Dia.


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## mickri

Aaron W I use a combination square to set the angle of tool bit.




X2 on ceramic.  I don't have a ceramic belt yet.  Still using 80 grit aluminum oxide.  That's all my local Ace Hardware had.  When they wear out I will get some ceramic belts.


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## DavidR8

I'm amazed that the 80 grit belts are producing such fine work. Fine as in not striated.


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## mikey

36 grit ceramic will chew through HSS faster than you would believe, and it does so with much less heat than Aluminum Oxide. 80 grit smooths out the coarse shaping marks and you can step up to as fine as you wish. If you step up to 600, you'll have a mirror finish.


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## mickri

This is where I plan to get my ceramic belts.  https://trugrit.com/product-categor...idth=or&filter_length=42&query_type_length=or  I am thinking about going with a 60 grit belt.  I'd rather not have to change belts.  60 grit seems like a reasonable compromise.


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## ttabbal

36 grit ceramic for roughing, 120 aluminum oxide to touch up and clean up the grind marks. 

I used to use finer grits before the honing, but it doesn't help enough to make it worth the extra effort to swap belts.


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## DavidR8

They’re here!
Super stoked to receive the tool samples today. 







Sent from my iPhone using Tapatalk


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## Forty Niner

A note of thanks to Mikey and Z2V. 
 I read the posts in this thread and finally asked to see the models, which were promptly sent to me.  It has helped me to fine tune the angles on my HSS tool bits.  I also decided to buy a belt sander after reading the positive experiences of other members.  Always improving and learning!


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## DavidR8

I bought a 2x27 belt & grinder combo yesterday. 


Sent from my iPhone using Tapatalk


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## mikey

Forty Niner said:


> A note of thanks to Mikey and Z2V.
> I read the posts in this thread and finally asked to see the models, which were promptly sent to me.  It has helped me to fine tune the angles on my HSS tool bits.  I also decided to buy a belt sander after reading the positive experiences of other members.  Always improving and learning!



I saw you post about your platen - now you, Will and Aukai have a Jet. You have to let us know how it works for tool grinding, okay? You did a nice job on your platen, Forty Niner, and that is so important when controlling your grind.


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## Forty Niner

mikey said:


> I saw you post about your platen - now you, Will and Aukai have a Jet. You have to let us know how it works for tool grinding, okay? You did a nice job on your platen, Forty Niner, and that is so important when controlling your grind.


I bought the Jet sander after reading all the accolades given to grinding tool bits on belt sanders.   I had never tried it before, so I thought it just might be time.  I  have only used bench grinders previously.  Now I find that I can remove metal faster and with good angle control using the belt sander.  It works great with the glass platen that I made for it.  However,  I think that I will still use my bench grinder for fine tuning and touch up.  It is a slow speed with fine grit wheels (rikon 8" 1800 rpm from Woodcraft)
I have two small lathes, a Sherline and a Taig.  And I have Boley and Levin watchmakers lathes.   So I primarily use 1/4, 3/16, and 1/8" HSS tool bits.  I have insert tooling for the Sherline and Taig, but prefer the HSS bits for most work.

As a side note, I have experimented with the "shear" style tool bit and find that it does work as advertised.  Easy to grind and produces a very nice finish on carbon steel.

Thanks to all the posts with all the great information on tool grinding.  I have improved my technique and reduced the grinding time.


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## Forty Niner

Made a helpful tool out of scrap aluminum to set the table angles.  One end is 8 degrees and the other 10.


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## Forty Niner

I needed a better way to hold my little HSS tool bits so I made a holder out of aluminum.  Very handy.  Works on belt sander and on grinder.  On the bench grinder I have the table set flat (0 degrees) and control the tool angle by the tool being above center of the wheel.


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## mikey

Forty Niner said:


> I bought the Jet sander after reading all the accolades given to grinding tool bits on belt sanders.   I had never tried it before, so I thought it just might be time.  I  have only used bench grinders previously.  Now I find that I can remove metal faster and with good angle control using the belt sander.  It works great with the glass platen that I made for it.  However,  I think that I will still use my bench grinder for fine tuning and touch up.  It is a slow speed with fine grit wheels (rikon 8" 1800 rpm from Woodcraft)
> I have two small lathes, a Sherline and a Taig.  And I have Boley and Levin watchmakers lathes.   So I primarily use 1/4, 3/16, and 1/8" HSS tool bits.  I have insert tooling for the Sherline and Taig, but prefer the HSS bits for most work.
> 
> As a side note, I have experimented with the "shear" style tool bit and find that it does work as advertised.  Easy to grind and produces a very nice finish on carbon steel.
> 
> Thanks to all the posts with all the great information on tool grinding.  I have improved my technique and reduced the grinding time.



I spent over a decade grinding tools on a bench grinder so I am very familiar with how it cuts. There is just no comparison to the speed and control a belt sander allows, and the glass platen keeps the face flat so no more dressing. I'm glad you see it, too.

Looks like you're grinding some really nice tools there, Sir!


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## finsruskw

What an awesome topic and project you have taken on!! 
Well, I do not have a lathe but I do have a fly cutter (W/O tooling) that I am itching to try out and have some HSS blanks on the way.
Questions:
Got through the 1st 104 replies so far and this looks to be for lathes only grinds??
Can I assume these tools will not work for that application?
And with out reading through the next 30 or so pages here, (which I do plan on doing as time allows) do you of have you any examples for fly cutter grinds?
Thank you!!


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## mikey

Thanks, finsruskw, and welcome to HM.

A HSS fly cutter tool is simply a left hand turning tool, like our Square tool. Put a 1/32" nose radius on it and I'll bet it works well for you. Gotta' run to an appointment but try asking @ttabbal about it - he made one.


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## benmychree

mikey said:


> Okay, a turning tool, facing tool and threading tool. This covers most general lathe operations. Anything else?
> 
> By the way, finishes are affected by the nose radius, relief angles and back rake. We'll make that clearer as we go along.
> 
> I never made a video, although I've thought about it.


In my high school machine shop class, we ground keystock tools until the teacher saw that we knew how to do it without wasting tool steel, we then received three new tool bits, ours for the class to be kept in our locker, the were ground into a roughing tool for turning, made with a chip breaker groove the full length of the cutting edge, a threading tool, and a ROUND NOSE or radius tool, used for radius and finishing work.  with these three tools, we were able to make all the required projects for the term, a hammer, screwdriver and paper punch.   I am suggesting that a round nose or radius tool be added to the list.  We used 1/4" square bits normally and ground a full radius (1/8") on it and a side rake.


----------



## mikey

benmychree said:


> I am suggesting that a round nose or radius tool be added to the list.  We used 1/4" square bits normally and ground a full radius (1/8") on it and a side rake.



John, are you referring to a round nose tool like this?




The one I use is like this one:




It has a 1/32" nose radius and no side or back rake. It cuts both ways and is really useful for between shoulders work. 

Either one is useful but I'm not sure which one you prefer. We can certainly add it to our list. In fact, I think we should.


----------



## WobblyHand

I'm looking to acquire a lower cost belt grinder.  The big 2x78s are over my budget, even in kit form.  Anyone know if the Dayton 3/4 HP 2x48 belt grinder is any good?  Dayton-grinder It's at Zoro and I've been emailed a 20% discount coupon.  That puts it at < $293 with free shipping.  It looks like a rebranded Palmgren.  It looks like the platen needs to be replaced, since its 2.5" not 2", but as noted, it's best to use a ceramic glass platen anyways.


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## mikey

Never saw this grinder before but it looks good to me. The chassis is stamped steel but heavy, which is good. The right side of the belt is open once the cover is off and nothing is in the way that would impede grinding rake angles on a tool so that is a very good thing. The platen is removable, I think; if so, you can replace it with a good platen with a glass liner on it. And it's got 3/4hp, more than enough to grind tools and for general shop use.

Looks good to me!


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## WobblyHand

Going to place the order - discount is good.


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## hman

A possible alternative is a Multitool accessory for an existing bench grinder - 2X 36" belt, 7" disk.





						Multitool USA
					






					multitool-usa.com


----------



## brino

Please let us know how it looks!
-brino


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## ttabbal

mikey said:


> Thanks, finsruskw, and welcome to HM.
> 
> A HSS fly cutter tool is simply a left hand turning tool, like our Square tool. Put a 1/32" nose radius on it and I'll bet it works well for you. Gotta' run to an appointment but try asking @ttabbal about it - he made one.



Pretty much exactly describes my HSS fly cutter. 15 degree LH square tool. I don't remember the radius, but 1/32 sounds about right...


----------



## finsruskw

I rec'd a piece of 3/8" HSS in todays post which I will set aside,  and my son is picking me up some key stock this afternoon.
I'll use the info from this thread and see what I can come up with even though a have not a clue what I am doing.
I have a  Sears 1/3HP bench top grinder and a Jet 4" belt sander so I think I am good to go in that dept.

However the most I can do for now, assuming I can grind a reasonable facsimile, is set it on the mill table and look at it!! Electrician still has not returned. I suspect he is being kept up at night fixing corn driers!!
If the offer is still open for the models, please include me.


----------



## mikey

finsruskw said:


> I rec'd a piece of 3/8" HSS in todays post which I will set aside,  and my son is picking me up some key stock this afternoon.
> I'll use the info from this thread and see what I can come up with even though a have not a clue what I am doing.
> I have a  Sears 1/3HP bench top grinder and a Jet 4" belt sander so I think I am good to go in that dept.
> 
> However the most I can do for now, assuming I can grind a reasonable facsimile, is set it on the mill table and look at it!! Electrician still has not returned. I suspect he is being kept up at night fixing corn driers!!
> If the offer is still open for the models, please include me.



PM @Z2V to have some models sent to you. That's what I would recommend. Then duplicate them and then stick with keystock to learn how to grind them consistently. All too many of us get too anxious and jump to HSS too early. It is better to be able to control your grinds so your tool geometry is accurate. When you can easily do this with keystock, THEN move to HSS and do the same thing. I promise you that the time spend grinding keystock will pay off.

Please keep us posted and show off your tools if you like - we like looking at that kind of stuff.


----------



## WobblyHand

mikey said:


> Never saw this grinder before but it looks good to me. The chassis is stamped steel but heavy, which is good. The right side of the belt is open once the cover is off and nothing is in the way that would impede grinding rake angles on a tool so that is a very good thing. The platen is removable, I think; if so, you can replace it with a good platen with a glass liner on it. And it's got 3/4hp, more than enough to grind tools and for general shop use.
> 
> Looks good to me!


Astoundingly, this Dayton belt grinder showed up on my doorstep this evening.  That's less than 24 hours!  I'm not sure it's fit for the task, although it's a sturdy beast.  3/4 HP motor, with thick metal to hold everything together.  Unfortunately the platen is also part of the frame as it is cast.  It's thick about 10.6mm.  I could grind away the platen on the right hand side, but not the left.  Can't add neoceram to the platen as the geometry of the wheel and platen surface are fixed.

Have a look at a few pictures.  Could I modify this enough to be ok?  Or should I attempt to send it back?
	

		
			
		

		
	



Integral platen 10.6mm thick.  Totally non-adjustable.


Almost all the blue you see is one casting, except for the little bit of sheet metal on the bottom right.  Platen extends about 1/4" on both sides, give or take.



Is this salvageable?  By that I mean, by grinding off the RHS of the platen, can it be useful for tool grinding?

From the parts diagram, item #28 (the platen) is all one piece.  I'll check to see if I can get a cost estimate for that part.  It is 9628668.01.



Should I send it back?  If I grind the right hand side of the platen to gain access to the right side of the belt, will this be sufficient?  Just don't have the funds to do the full 2x78 knife grinder, or for that matter, even the Jet.


----------



## ttabbal

Can you get the belt to ride on the edge of the platen? I bet you could make it work good enough for tools.

The knife maker 2x72s don't have to be super expensive. Here's one place to start. 









						BG-272 DIY 2 x 72" Belt Grinder
					

DIY 2" x 72" Belt Grinder Project   Like almost every newbie knifemaker owning a decent belt grinder is dream. When I realized the price of...




					dcknives.blogspot.com


----------



## WobblyHand

@ttabbal At the moment, I don't see how, short of physically grinding part of the platen on the right hand side.  The platen is 1/4" nominally wider than the belt on both sides.  So if I ground off 1/4" on the right hand side and I modified the belt cover to come in 1/4" maybe.  The belt is 1/8" away from the edge of the pulley, so I can't see pushing it much further.   Actually I don't know how well the belt tracks just yet as I've yet to plug it in.  I don't have a place to tie it down yet.  It was delivered in a day, and I wasn't expecting that!  

If I did grind the platen on one side and alter the cover to allow the tool to be tilted 15-20 degrees backward, would that be sufficient?  Or should I return this grinder?  Seriously, the grinder seems like it's built quite well, like a tank, but it's not a blade builder's delight.  I just don't have the experience with grinding these tools to make a good evaluation.  So that's why I'm asking for guidance and or advice.

I read through that link earlier in my research.  It seems like a fun project.  At the moment, I want to actually be able to use my lathe, not take on a whole mess of extra projects.  Someday I'd like to try building the big 2x78.  Right now, I can't take it on.


----------



## brino

WobblyHand said:


> Should I send it back? If I grind the right hand side of the platen to gain access to the right side of the belt, will this be sufficient?



WobblyHand,

It all depends on what you're after.

Cutting out the entire platen of this machine to build in a special ceramic one is probably more work than building new grinder around a new platen.

However, if it is simple access to one edge of the belt that you are after then perhaps you can modify it much like I did to mine here:
https://www.hobby-machinist.com/thr...-sander-to-access-the-edge-of-the-belt.63436/

I did mine so I could grind lathe tools as outlined in this thread.
A small slot in that thick casting at the right of the belt should do it.
If you decide to modify it then add the slot where you can have a small support table too.

Your sander looks much more robust than mine!

-brino


----------



## WobblyHand

Brino,

I agree.  This grinder is not worth modifying to put in a neoceram platen.  Too much machine work.  I don't have the machines to do it, and wouldn't want to pay someone for it.  It would be cheaper to buy a fancy blade grinder!

What I'm asking is:  Is it sufficient (for the purpose of grinding lathe tool bits) to add access to one side for this grinder?
If so, I think I could grind out a chunk of the platen on the right hand side with out any problem.  Maybe 1" high by 1/4" deep.  That should be good enough to handle my 3/8" tooling.  I'd have to alter the belt cover door a little as well.

The grinder has a pretty heavy support table included.  It mounts to the left side of the grinder.  I just didn't assemble that part - so it wasn't in the picture.  One last change I'd have to do is to add a small support for the tool on the right side.  Guess I'd just make a plate that bolted on top of the existing support table.

Hmm, this is sounding better!  I think I'll keep it!

WH


----------



## mikey

It's disappointing that the platen is part of the body of the grinder. I think we've seen this construction before but I forgot about the possibility. Sorry about that. 

Before you go modifying your platen, let's think this through. Once you cut a piece out of it, the grinder will become usable for tool grinding but it also makes it less usable for grinding other stuff because you'll have a part of the belt without any support under it. 

Thinking this through, I know how important a glass platen is. That steel platen will not last long and you'll wear a divot into it in short order. I would send it back and build a 2x72 myself.


----------



## ttabbal

I have to defer to Mike on the existing grinder. I have only used my 2x72. If you have a welder or know someone who does, it's not a difficult or time consuming build. You can even get the metal cut to length for you at most suppliers.

If it's really about the desire to make chips on the lathe, would it help if I grind you a square tool to start with? I have some 3/8 bits here... I hate to see you work harder on a less useful (for this anyway) tool than you would on a better grinder.


----------



## WobblyHand

If I just cut out a 1" H x 1/4"W piece of the platen on the right, why wouldn't it be ok for grinding other stuff?

I hear you on the steel platen.  This one is not modifiable to glass.  And since it's a relatively big and complex piece, it's bound to be an expensive replacement part.  How long do you think the platen would last?  A month of moderate use?  More?  Less?


----------



## WobblyHand

@ttabbal I've got loads of welders!  Seriously, welding isn't a problem.  It's that I priced things out and it seems like the piece parts are in excess of $500.  Right now, I can't swing that.  I can't fab/cut/hog out the pieces simply because I don't have the tools to do it.  I can weld the pieces together.  A 2x72 would be great, but I just don't need that project right now.  Maybe in the summer, but not now.  A guy just has to know when to fold his hand.  So I'm folding the 2x72 hand - at least for now.

I do want to make chips.  Actually I want to make something, not just make chips.  My carbide bits just aren't giving me the finish I want with my little mini-lathe.  I don't have any HSS yet, (probably be here by New Years) but I do have 5 pieces of 5% cobalt in 3/8".  

I'm still mulling over this grinder.  Not quite sure what to do.


----------



## WobblyHand

@ttabbal What can I use the square cutter for?  Not familiar with it's use.


----------



## Z2V

Do you have a bench grinder you can grind tool bits on until you can fit a belt grinder into your schedule?


----------



## WobblyHand

Sort of, with some work.  I'd have to buy new wheels, and fab up a tool rest.  The tool rest on my bench grinder is just flimsy sheet metal.


----------



## Z2V

It’s worth a thought. Use the bench grinder while you accumulate the material and time to do it right and build a 2x72 .
Every time I drive by a metal supply house I stop in and check out the drop zone. It took me a few months to get all the metal I needed but it all came from drops bought by the pound. Keep an eye on Craigslist for a free treadmill and harvest the motor and control board out of it. Many of us here are using treadmill motors on our grinders.


----------



## WobblyHand

What kind of grinding wheel is suitable for HSS?  HSS with 5% cobalt?  Suggested grit(s)?  

Good idea on checking for drops.  I'll keep my eye out for treadmills.


----------



## mikey

WobblyHand said:


> If I just cut out a 1" H x 1/4"W piece of the platen on the right, why wouldn't it be ok for grinding other stuff?
> 
> I hear you on the steel platen.  This one is not modifiable to glass.  And since it's a relatively big and complex piece, it's bound to be an expensive replacement part.  How long do you think the platen would last?  A month of moderate use?  More?  Less?



If the platen was tool steel, then maybe many months. However, if it is mild steel welded on, then I dunno' ... a few months before you have a noticeable divot. I know on the angle iron platen on my Craftsman grinder, I can make a divot on that within a few weeks when I'm grinding tools. You see the wear mostly on the right side, where you grind the rake angles. 

It's your call but I would suggest you build a 2 x 72 or go for one of the cheap 2 x 42 Palmgren belt sanders and use ceramic belts. The two key things: a glass platen liner and a good tool rest that is settable to precise angles.


----------



## mikey

WobblyHand said:


> @ttabbal What can I use the square cutter for?  Not familiar with it's use.



He is offering to grind a Square tool for you. This is the general purpose turning tool introduced in this thread as one of the three tools in the model set. If I were you, I would take @ttabbal up on his kind offer. I know personally that he grinds good tools! Then you'll have a tool to use while you decide on which belt sander to buy or make. If you hone it and take care of it, it might last you about a decade or more ... sounds like a good deal to me!  

Props to you, Travis!


----------



## ttabbal

I'm shocked that the steel is coming in over 500. I could swear I got mine for about 200 not that long ago. Metal Supermarket, new cut to order. Though I did just have a few cuts done, I had a bandsaw at that point, so I just needed manageable sizes. I don't think I'm 500 all in with a good deal on a 3ph motor, wheels, and VFD, though I did go cheap on the VFD.

The square tool is what I use for about 90% of my turning. If a different type is needed for your project, I can probably make it. Just trying to get you going so you can make what you need to while you decide on the grinder setup you want to use. I'd hate to see someone settle on a grinder they don't want just for lack of a lathe tool.


----------



## Z2V

WobblyHand said:


> What kind of grinding wheel is suitable for HSS?  HSS with 5% cobalt?  Suggested grit(s)?
> 
> Good idea on checking for drops.  I'll keep my eye out for treadmills.



My grinder has Aluminum Oxide wheels with somewhere around 60 and 30 grit wheels on it , best of my recollection.


----------



## ddickey

How far away from you is this?








						Rare Porter Cable WG4 Wet/Dry Belt Sander
					

Hiya, I have a Porter Cable freestanding belt sander for sale. It is a WG4 model which means that it is designed for wet and dry use. There is a lower tank and a catch basin for it so that it can...



					boston.craigslist.org


----------



## brino

mikey said:


> Once you cut a piece out of it, the grinder will become usable for tool grinding but it also makes it less usable for grinding other stuff because you'll have a part of the belt without any support under it.



A small notch (like the one I cut on mine at the link I provided above) does not compromise using the sander for other functions.
There is no unsupported part of the sanding belt.

For mine the notch is near one edge. I typically keep the belt centred, and only move it over to the edge of the notch when grinding lathe tools.
The belt tracking adjustment (that simply tilts the upper roller) is enough to do that.



WobblyHand said:


> How long do you think the platen would last? A month of moderate use? More? Less?



I have had my old sander with a steel platen for around 15 years.
I use it heavily for wood, aluminum and steel.
I cut the notch in the side over two years ago (by the date on that other thread).
There is NO divot sanded into the steel platen.
If it died today, I would buy a smiliar one tomorrow......and cut the same notch, but maybe faster with a hand-held angle grinder.

-brino


----------



## WobblyHand

Wow, lots of responses!  And quite varied in opinion!  
@ttabbal I'd like to take you up on your offer.  I'll PM you with my address and details.  This will at least get me going.

Looking at 2x72 again, it doesn't look that bad.  Maybe I was up too late, or having a bad day.  I dunno.  The 2x72 is doable.  I certainly can fab the frame and cut the tubing with my horizontal bandsaw.  I might even have a stick of some comparable square steel tubing in my garage, although not sure about the size.  By a weird coincidence, I had a treadmill offered to me, a few months ago, but I let it go.  At the time, I had no need for it.  Oh well, have to look for another one.  The $500 was looking at kits - not pricing raw steel.  To bring the cost of the 2x72 down, I'll have to put in more work.

The Dayton platen is cast - so long term it's not the best.  The material is unknown, could be cast iron, or steel.  But... I could use it to help make the 2x72, and it could grind a few tools along the way.  It has a single axis adjustable rest which is pretty beefy, not the tinfoil that's on my under powered bench grinder.  I could use it for a while.  When or if the platen eventually fails, I will still have the 3/4 HP motor, the pulleys, etc.  Hopefully by the time it fails/degrades too bad, the 2x72 will be finished.  According to @brino's experience on his grinder, the Dayton probably won't evaporate it's platen overnight.  I have ceramic belts on order, so I hope that the fast cutting of the ceramic will help reduce the platen pressure.

So, that's the plan, going to do both!  Can't have too many (tools) grinders, right?


----------



## WobblyHand

ddickey said:


> How far away from you is this?
> 
> 
> 
> 
> 
> 
> 
> 
> Rare Porter Cable WG4 Wet/Dry Belt Sander
> 
> 
> Hiya, I have a Porter Cable freestanding belt sander for sale. It is a WG4 model which means that it is designed for wet and dry use. There is a lower tank and a catch basin for it so that it can...
> 
> 
> 
> boston.craigslist.org


Close enough as far as location.  That thing looks heavy and interesting.  A little too heavy for me to maneuver down the 26" wide steps into my basement.  Think "This Old House".

If I had a different shop setup, I'd check it out.  I think I'll build a 2x72.  Cash outlay would be less for me, and a little more spread out over time.


----------



## ttabbal

The crew here tries to be helpful. Sometimes we try to spend more of your money, but it's usually for a good reason. Let me know the address, and if a 3/8" 15 degree square tool will get you going or if you need some changes.

I agree, more tools is better. If you can fit them in the space. I think I've reached the limit of the space I can take over and remain married. Something about wanting to put cars in the garage... Pffftt..


----------



## WobblyHand

Basement is only place left I have.  Welders, compressor, etc. took over the garage long ago...


----------



## mikey

brino said:


> A small notch (like the one I cut on mine at the link I provided above) does not compromise using the sander for other functions.
> There is no unsupported part of the sanding belt.



Just curious, Brino. How wide is your platen? If I cut a notch out of my 2" wide platen, even a small one, then I would have an unsupported area under the belt.




brino said:


> I have had my old sander with a steel platen for around 15 years.
> I use it heavily for wood, aluminum and steel.
> I cut the notch in the side over two years ago (by the date on that other thread).
> There is NO divot sanded into the steel platen.
> If it died today, I would buy a smiliar one tomorrow......and cut the same notch, but maybe faster with a hand-held angle grinder.



I would imagine the steel used in various platens varies a lot. Mine divots with light use, or it sure seems that way. I tend to grind tools in batches. Since the belt splices don't last more than about a year or so for me, I tend to buy new belts and then grind a whole bunch of tools within a month or so, so I do tend to use the belt sander heavily at times.

Back when I was looking for a solution and discovered the knife guys were using Pyroceram liners, I queried the knifemakers on one of their forums about using a glass liner and why they felt the need. Almost all of them told me that they were wearing their platens way too fast and that matched my experience as well. This must have been about 20 years ago. I put a glass liner on my platen and am now on my second liner but only because the first one broke loose from the epoxy bond, not because it wore down. That platen liner is, by far, the best thing I ever did for my belt sander.


----------



## Stonebriar

Mikey what do you think about this as an option for a sander to use?









						Shop Fox Knife Belt Sander/Buffer W1843 - The Home Depot
					

Very popular with knife makers, this Knife Belt Sander/Buffer features a cool-running 2 in. x 72 in. abrasive belt and an extended buffing wheel shaft for full-access buffing or stropping. The sanding



					www.homedepot.com


----------



## mikey

That sander has a similar design to the Kalamazoo belt sanders. See the single tubular arm that supports the upper wheel? I've seen a fair number of negative reviews on this design. They say it tends to move in use but this is heresay. Check out a Kalamazoo belt sander on youtube and you'll see what I mean.

I would definitely look for a KMG-type 2x72 instead. You can make one for less or buy one for nearly the same price.


----------



## brino

mikey said:


> Just curious, Brino. How wide is your platen? If I cut a notch out of my 2" wide platen, even a small one, then I would have an unsupported area under the belt.



Hi Mikey,

Yep, that's the difference.
My platen is almost 5 inches wide and it takes a 4 inch wide belt.
That leaves a frame or margin at both sides of the belt that stopped me from using the very edge of the belt.

The sander that @WobblyHand received looks similar to mine, but MUCH heavier.

I think the pictures below show it best.......that's what I based my suggestion for the modification on.


1) Here's your picture from: https://www.hobby-machinist.com/threads/models-for-grinding-hss-lathe-tools.62111/post-514226


Nothing stopping you from using the very edge of the belt!

2) here's a picture of my sander from:  https://www.hobby-machinist.com/thr...access-the-edge-of-the-belt.63436/post-523646


Without the notch, I cannot make the same cut you show above as the frame is in the way.
With the notch, I simply adjust the belt tracking to get it at the edge of the notch and grind away.


3) and a picture of @WobblyHand 's sander from: https://www.hobby-machinist.com/threads/models-for-grinding-hss-lathe-tools.62111/post-702969


It looks like a 2inch wide belt and about a 3 inch wide platen. (plus guards on each side)
I believe he could do the same modification I did to use the very edge of the belt.
(He may need to notch the right-hand belt guard, too)

-brino


----------



## mikey

Thank you for making that crystal clear, Brino. I understand what you did and why you're able to fully support the belt. There is no question that your mod will allow you to grind your rake angles effectively while also having a lot of real estate to grind the rest of the tool, along with anything else you need to work on. Appreciate you clarifying that for me!


----------



## finsruskw

I have a fairly new Sears 6" bench grinder, 1/3 HP.
Is this enough oomph for grinding tool bits?
What type wheels should I use?
The only ones available around here are worthless, you can actually see them wearing away as you grind a bolt or anything else for that matter.
My gut tells me I need a bigger unit w/more HP.

I feel a ;lathe is on my radar scope for sometime this winter/spring.
How many of you guys, if any, are running an Atlas?


----------



## mcdanlj

finsruskw said:


> Is this enough oomph for grinding tool bits?



It's just time. And if you are looking at small lathe and something like the inexpensive 50-pack of 3/8" blanks linked (much) earlier in this thread from ebay seller niuniucme, it's less time than if you are going to be cutting 1/2" blanks... I have cut the square tool in 1/2" HSS on my 1/2 HP bench grinder with 60 grit norton white aluminum oxide wheel, finished on 120 grit and then honed, and it was a bit of an exercise in patience. I'm torn between "what's the rush?" and "it would be a lot of fun to build a 2x72" — so far, "what's the rush" has won.


----------



## mikey

I own a Sears 6" bench grinder and yes, it will grind tools. If you plan to use it to grind HSS lathe tools then I would suggest you consider CBN wheels for it. The wheels are intended to grind HSS and will probably last your lifetime. They do not need dressing, they do not blow up and they will far outlast an abrasive wheel.


----------



## finsruskw

WOW!
They sure are proud of those, huh??!!
But, I guess it's like many things in life, You want to play,.... you have to.......


----------



## Dhal22

Doing tons of reading while I think through lathe options.  Time to join this thread I think.  Grinder or belt sander?  I have both.


----------



## finsruskw

Any reason why I cannot use plain 3/8" x 3/8" bar stock for practice grinds?\
A 5'chunk of it can be had or practically pennies.


----------



## tweinke

finsruskw said:


> Any reason why I cannot use plain 3/8" x 3/8" bar stock for practice grinds?\
> A 5'chunk of it can be had or practically pennies.



There is no reason you can't use bar stock, the keystock was suggested because its relatively cheap and grinds easily


----------



## WobblyHand

Been busy.  First I cut a notch in the side of my 2x48 grinder.  I used a 7" portable grinder, that I could barely control.  That thing was heavy and had a lot of gyroscopic movement.  It wasn't pretty.  But, it's done.  Then I made a rest extension so I could support the tool bits when doing the rake.


Then I coarse ground 3 tool bits using 40 grit ceramic.  The ceramic grit cuts keystock pretty quickly.  Here are the 3 bits from the top, side and end.




On the side view of the knife bit, you can see a 2 stage grind, right about where the mark is.  I had to grind in two stages, because I don't have full access on the left side of the belt.  By grinding in stages, I was able to create the knife edge.  

A special shout out to @ttabbal who sent me a beauty of a bit!  Thanks Travis!



To the question section.  I have an assortment of ceramic belts.  (36 to 120 grit)  I used a 40 grit.  It's fast, but as you can see, (in my bits) it leaves pretty deep gouges.  When do you switch grits?  At what stage of the grinding?  What is recommended?  I can see it's kind of easy to sort of get the first grind ok - but it looks like it's also easy to mess things up in later stages.


----------



## mikey

You're doing great! Your overall tool shapes and angles look really good to me. And yes, Travis is awesome!

I usually use a coarse grit to shape as you did above, then switch to an 80 grit belt to remove the coarse grind marks, then I hone. However, you can step your way up through the grits if you prefer. What you are trying to accomplish when changing belt is to remove the grind marks from the belt before. You will find that going from a 32 grit to 80 grit belt, then switching to a coarse, then fine, then extra-fine diamond stone works well for lathe tools. 

The only time I step up through multiple grits is when I need a tool for precision turning. I will shape at 32, smooth at 80, refine at 120 and then quickly step up through the remaining grits until I hit 600 grit. Then I use a fine India stone to remove belt marks, then a flat Translucent Arkansas stone to produce a mirror finish. That tool will take off a tenth in steel.


----------



## DavidR8

Those look great @WobblyHand !

@mikey what type of hone do you recommend? 
I have a fine diamond home. 


Sent from my iPhone using Tapatalk


----------



## ttabbal

I usually do about the same thing Mikey does. 36 ceramic to shape, then a 80 or 120 AO, quick touch to get most of the marks, then hone with 3 grades of diamond cards.

Watch the angles when you switch belts or reposition, dip in water, etc.. It's easy to make the tool look like you're cutting a gemstone. I find it helps to line up and firmly press into the platen. It's more about practice than anything else. And HSS being harder to grind helps a little there. 

I have belts to 800 I believe, but I bought them for polishing knife blades, not tool making. I tried it once, but it wasn't really useful. The time spent swapping didn't save enough time honing for tools. One of these days I should make a knife...


----------



## mikey

I use this set from Amazon for honing after shaping a new tool. If I have a lot of them to do, I use DMT 8" dia-sharp bench stones. 

I've been thinking about trying a CBN stone. Here is the one I'm considering. It has 80 grit on one side and 1000 grit on the other.


----------



## WobblyHand

Do you recommend switching belts to finer grits while practicing on keystock, or only on HSS?  I'm thinking of saving these for a shape reference since I seemed to have gotten them right.


----------



## mikey

I would switch grits for your HSS bit's. Stick with keystock until you're comfortable with grinding, then switch to HSS.


----------



## WobblyHand

Mikey, thanks for the advice.  This has been such a helpful and informative thread.

Grinding keystock seemed pretty easy - modifying the grinder and making the table extension was a lot harder for me.  Controlling the keystock wasn't difficult.  Nonetheless, I'll grind another keystock set, just to see if was just beginner's luck.    Have to hook up the vacuum cleaner to the grinder, it's making a mess.

All that will have to wait until the next decade.  Umm, I mean tomorrow.  Happy New Years everyone!


----------



## tweinke

WobblyHand said:


> Mikey, thanks for the advice.  This has been such a helpful and informative thread.
> 
> Grinding keystock seemed pretty easy - modifying the grinder and making the table extension was a lot harder for me.  Controlling the keystock wasn't difficult.  Nonetheless, I'll grind another keystock set, just to see if was just beginner's luck.    Have to hook up the vacuum cleaner to the grinder, it's making a mess.
> 
> All that will have to wait until the next decade.  Umm, I mean tomorrow.  Happy New Years everyone!



When I need practice or any time I grind bits getting the angle to continue grinding is probably the hardest part ( Like after a belt change ). That for me was the toughest thing.


----------



## mikey

WobblyHand said:


> Mikey, thanks for the advice.  This has been such a helpful and informative thread.
> 
> Grinding keystock seemed pretty easy - modifying the grinder and making the table extension was a lot harder for me.  Controlling the keystock wasn't difficult.  Nonetheless, I'll grind another keystock set, just to see if was just beginner's luck.    Have to hook up the vacuum cleaner to the grinder, it's making a mess.
> 
> All that will have to wait until the next decade.  Umm, I mean tomorrow.  Happy New Years everyone!



You're welcome. 

Even after all this time, I still grind on keystock when I'm considering a new tool. Sometimes I just need to see the tool angles and keystock helps me to do that.


----------



## mikey

tweinke said:


> When I need practice or any time I grind bits getting the angle to continue grinding is probably the hardest part ( Like after a belt change ). That for me was the toughest thing.



I used to have a tough time with this, too, until I figured out how to align the flat I was grinding so it was parallel to the platen. Then all my alignment issues (and facets) disappeared.


----------



## mikey

This thread has brought a lot of us together to share and learn and appreciate how we've all grown. I want to thank you all for making this thread so much fun and I hope 2020 is a great year for all of us.


----------



## tweinke

I wish to thank everyone involved in this thread the experts the beginners everyone ! With all the information, questions and comments this has turned into a very informative source of info for us beginners. Thank you to all and wish all a happy 2020


----------



## ttabbal

This is one of the best threads on any forum I've ever seen. It's everyone contributing to helping us all learn and improve. Great group here and hopefully we keep getting new people to learn and learn from.

I started out wanting to send my HSS to @mikey, and discovered that I enjoy grinding tools almost as much as using them!


----------



## WobblyHand

Made a second set in keystock.  Came out pretty much like the first set.  On the second set I used an 80 grit belt after the 40 grit.  It's a little harder to maintain the right angles after switching the belts as some of your reference lines got ground off, but not too bad.  The threading point is a little hard to maintain exactly at 60 degrees.  Both my thread cutter angles (on the keystock) are very slightly off.  I suppose that will just take practice.

So, this made me brave enough to try some HSS.  I have some 8x8x200mm HSS.  I cut the 200mm piece into thirds.  Each piece is 66mm long, give or take.  (2.6 inches)  It's a little awkward holding the smaller piece, but not bad.  I cut a square tool, first using 40 grit ceramic and then 80 grit ceramic.  I then cleaned it up using 2 diamond cards.  (325 grit and 600 grit).   Using the 80 grit belt makes the diamond clean up a lot easier.  Maybe next time I will also use my 120 grit ceramic belt.  I found it a little difficult maintaining nice flat faces, especially on the smallest face.  It's hard to avoid rocking the face relative to the card.  Is there a trick to keeping it flat?  Mind you, I'm doing this by hand.  I also have a 1200 grit card, but am wondering about diminishing returns.  (And holding it flat relative to the face.)


	

		
			
		

		
	
You can see some deeper gouges that I didn't get out.  It just needs to be super smooth at the tip?  Also the angle of the tip is slightly more acute than the keystock example I ground.  Is this a problem?


	

		
			
		

		
	
This face is easy to polish with the cards.


	

		
			
		

		
	
There is a tiny flat spot near the tip. Next photo is a better one of that face.
	

		
			
		

		
	




How can I do better on this?   Practice, practice, and practice some more?  Soon I'll have some 3/8" HSS to work on.  I think the larger size is easier to hold when grinding.


----------



## mikey

The overall shape of the tool is not critical and will become more consistent with time and practice. 

Yes, honing is hard in the beginning but it gets better and easier with practice and time. I've been doing it for over 30 years and I think I'm finally getting a handle on it. That end face is the toughest because it is so small that it doesn't self-register. You must lock your wrists and concentrate. I find that applying pressure only on the pull stroke works best for me. 

When you grind your tool on a belt sander, the goal is to flatten the entire face; there should be no shiny spots like up near the tip on the end cutting face. When you grind on a wheel, you can just hone the upper and lower edges but you must hone all the way to the edge. The reason for this flattening thing is that you are creating flat planes that intersect with each other; that is what produces your cutting edges. If these intersections are not clean and consistent then your edges will not be sharp and the tool will not cut well. 

Be patient, hone carefully and it will come.


----------



## Stonebriar

Well I guess I am going to build a sander.  I would prefer to use a 110 motor.  Is NOT being a three phase motor with the vfd going to be a problem grinding the tool bits?


----------



## brino

Stonebriar said:


> Well I guess I am going to build a sander. I would prefer to use a 110 motor. Is NOT being a three phase motor with the vfd going to be a problem grinding the tool bits?



It shouldn't be a problem.
I use my 120VAC 6A sander shown here:
https://www.hobby-machinist.com/thr...-sander-to-access-the-edge-of-the-belt.63436/

It's really about the belt speed, which I think is covered in the thread somewhere......

It's not a Cadillac, but it gets me there.

-brino


----------



## mikey

My belt sander uses a 3450 rpm single phase motor and it works okay for me.


----------



## ttabbal

Single phase is fine. I use the variable speed because I have it, but I could do it without. You can also use step pulleys. There are a number of calculators online that can help determine the best pulley sizes and such. I really like VFDs. I have 4 of them running in the shop now.


----------



## finsruskw

The models showed up in the mail box this morning.
Looks like I will have to get busy and give this a whirl and burn my way   through a 5' chunk of 3/8" stock!!
Thanks to Bruce for sending them my way.
I assume someone will be in touch w/info on who to send them to next.

An aside, the electricians are supposed to be here on Wed to wire up my mill,,,,finally!


----------



## Z2V

PM sent


----------



## finsruskw

Z2V said:


> PM sent



Thanks Jeff!!
Hope to be grinding soon as I can find some belts for this used $100 off brand "Tool Shop" brand belt unit I picked up a few years back. Was impressed by the heavy full length platen and I should be able to notch the right side for grinding as needed. 
Would be a good 1st project for my mill I have yet to use.

 I will have to raise the table some as there is no support immediately behind it towards the bottom of the platen.


----------



## DavidR8

Wow! That thing is seriously built!


----------



## Z2V

Yep, that is one heck of a grinder. Is the angle of the work table adjustable?


----------



## finsruskw

Z2V said:


> Yep, that is one heck of a grinder. Is the angle of the work table adjustable?


Yes it is but I'll have to find a better way to check the angles other than what is on there.
Has  knob for adjustment but the table when adjusted will move if you even look at it cross eyed
I scrounged an AO 100 grit belt and tried my hand at some of the angles you all have been talking about but will have to find a tool of some sort to check them with while grinding. Good thing I have plenty of 3/8" rod to waste!!
Also have a 40 grit as well, AO

By the looks of the platen it really shouldn't miss a little chunk out of one side.


----------



## brino

Z2V said:


> Yep, that is one heck of a grinder. Is the angle of the work table adjustable?





finsruskw said:


> Yes it is but I'll have to find a better way to check the angles other than what is on there.
> Has knob for adjustment but the table when adjusted will move if you even look at it cross eyed



I cannot tell on yours, but on mine the table was only fixed at one end with a threaded hole and that wasn't enough.
That hole stripped quickly, so I drilled a hole aligned thru both sides to use a longer (6"?) piece of all-thread and some washers and nuts.
I have meant to make a new table with supports to both sides, but haven;t done that step yet.

It looks like your sander already has a couple holes you could use for a better table mount:






finsruskw said:


> By the looks of the platen it really shouldn't miss a little chunk out of one side.



Agreed! It's heavier than the one I hacked up: 
https://www.hobby-machinist.com/thr...access-the-edge-of-the-belt.63436/post-523646

-brino


----------



## finsruskw

It looks like your sander already has a couple holes you could use for a better table mount:
View attachment 309760


Those are the threaded holes for the back side belt guard.
But I suppose they could be incorporated into a tool rest as well with a little thought.
Thanks for the idea!!
I was thinking along the lines of making a riser for the existing table to raise it for 90*work.
After I made that last post I discovered that when the rest is tilted for grinding say, the 15* angles, the side nearest the belt raises enough so the tool/belt presses against the platen.

It also does not have a miter slide although the table has a 5/8" slot for one, to narrow for the 3/4"slide from my Craftsman table saw. So making one of those, soon as my mill is up and running (hopefully tomorrow) is at the top of my to-do list. I have another that I can modify for that use but it will have to be narrowed on each side to fit the slot as well.

Can one of you folks suggest a decent tool for checking the angles on these bits while grinding them?
Was thinking of a square head protractor but many of the reviews on Amazon are not the best.
This $5 e-bay find showed up in the mail this morning w/free shipping!!


----------



## mikey

finsruskw said:


> I was thinking along the lines of making a riser for the existing table to raise it for 90*work.
> After I made that last post I discovered that when the rest is tilted for grinding say, the 15* angles, the side nearest the belt raises enough so the tool/belt presses against the platen.



You may have to grind the part of the table adjacent to the belt to achieve the angles you need, at least for now. Your table looks like cast aluminum and you'll find that it will catch and drag on steel tools. Maybe consider making a table from steel that is adjustable for angles but also for distance from the table to the belt.



finsruskw said:


> Can one of you folks suggest a decent tool for checking the angles on these bits while grinding them?
> Was thinking of a square head protractor but many of the reviews on Amazon are not the best.



The best tool for checking table angles is a digital protractor, at least in my opinion. I use the one from Beall Tools but any of the import ones will work.


----------



## finsruskw

Like this one?








						General Tools - Pro-Angle Digital Protractor, Model 1702
					

The UltraTECH Pro-ANGLE Digital Protractor displays absolute and relative angle measurements in a large easy-to-read LCD window making it the perfect tool for installing cr




					www.woodcraft.com


----------



## mikey

I use a Starrett C-493B. You can find them on ebay and Amazon. I recommend these for beginners but later on, you will not need it. You can easily duplicate an 80 degree angle by eye.

For table angles, you can use the electronic ones. I use this one but there are many others.


----------



## ddickey

Or,








						6" PEC Semi-Circular Head Protractor 5180 Name Removed 2nd
					

6" PEC Semi-Circular Head Protractor 5180 Name Removed 2nd




					www.harryepstein.com


----------



## Z2V

I keep it simple and inexpensive with these from HD


For the table angles and this for finding the angles on the tool.


----------



## tmenyc

mikey said:


> I own a Sears 6" bench grinder and yes, it will grind tools. If you plan to use it to grind HSS lathe tools then I would suggest you consider CBN wheels for it. The wheels are intended to grind HSS and will probably last your lifetime. They do not need dressing, they do not blow up and they will far outlast an abrasive wheel.


Mike,
how is possible, that in all the Mike lectures I've read (and received on the side) about grinding HSS and part carbide tools, that this is the first mention of CBN wheels I've seen?  In my small apartment shop and with my Dewalt 6" bench grinder, the real drawback for me with grinding has been the mess caused by dressing the wheel.  If CBN doesn't need dressing, it would be a huge improvement for my shop practice and let me grind tools far more often.  In fact I enjoy doing it! What brand do you recommend?  

Also, all the best for 2020, and let's keep this amazing thread going.  I've told people on my regular fountain pen board about it, and they find it hard to believe that such a thing as this board and this thread exists.  Many thanks for the leadership, Mike. 

Tim


----------



## mikey

My apologies, Tim. Yeah, if you use a bench grinder to grind lathe tools then CBN wheels are a very good option. The advantages are in the quote you cited. In addition, they have wheels that allow you to grind on the sides of the wheel without the usual risk of an exploding wheel because they are solid 6061 aluminum. There is no question in my mind that if I used a bench grinder for tool grinding then I would be using CBN wheels.

I got scolded by one of my wood turning friends for the very same thing you brought up. I suggested to him that he email Ken Rizza at Wood Turners Wonders to obtain wheels from a very good source. I suggested he get at least one Mega Square wheel and another of his choice, which he did. They work so much better and cleaner than abrasive wheels and he is much happier. I would avoid any wheel with a radiused edge as it will not work well for metal lathe tooling.

I believe they also have 6" wheels but since these wheels cannot explode, it should be safe enough to use without a wheel guard. If so, then you might be able to use an 8" wheel on a 6" grinder. Ask Ken what he thinks. He will also be able to advise you on which grits will work for shaping and finishing. These wheels are expensive but they will probably last you the rest of your life so if you plan to stick with your bench grinder, it might be good investment.

You might also discuss buying a package. He sells Ryobi grinders plus the wheels at a very competitive price and that might be an even better option.

Thanks for the kind words and for promoting HM on your pen forum. They can read this thread and even participate if they wish but HM offers so much more so tell them to come on over!


----------



## tmenyc

thanks, Mike.  I just wrote to him.  There are no 6" wheels on the site but I'm hoping he'll be able to help.  

Tim


----------



## tmenyc

I've corresponded with Ken, and he'll build a 6" wheel for around $100, which is a lot but well worth it to not have to deal with the mess of dressing wheels again. I'm leaning to staying with 6" but might go to 8 for the shape advantage.  If I were to go this route, what is the right grit level?  Is it useable for other, less particular grinding, or must I pull it off and put the other back on each time I want to grind a screw down or something?  Is it quicker at grinding HSS tools than the AO is?  I'd be curious to hear the experience of anyone on this thread with CBN wheels.
Many thanks,
Tim


----------



## finsruskw

tmenyc said:


> I've corresponded with Ken, and he'll build a 6" wheel for around $100, which is a lot but well worth it to not have to deal with the mess of dressing wheels again. I'm leaning to staying with 6" but might go to 8 for the shape advantage.  If I were to go this route, what is the right grit level?  Is it useable for other, less particular grinding, or must I pull it off and put the other back on each time I want to grind a screw down or something?  Is it quicker at grinding HSS tools than the AO is?  I'd be curious to hear the experience of anyone on this thread with CBN wheels.
> Many thanks,
> Tim



Do you think he would do 2 of them?
Yours plus one more?
If so, Id be up for one as well.
BTW, how on earth does one build a wheel?
Is that the business he is in?


----------



## tmenyc

Fin,
check out his website, link a few posts up in Mike's.  I've also gotten what I think are the right answers to my questions.  180 grit CBN is the right grit; it corresponds to 80 grit AO.  These are only good for turning tools, not for utility grinding.  They are said to be a lot quicker. and definitely cooler, so the constant dunking goes away too. 
I'll ask if he'll do two 6" with separate shipping.  I don't imagine he wouldn't, will ask.  Check out this  video; it's the best I saw.  I'm not a woodworker, so can't vouch for it, but it seems to be on the up-and-up.
If anyone can contribute more to this, I'd be appreciative.  As I've said before, I'm not loath to spend $100 for this if it's a solution, but not if it isn't. 
Thanks!
Tim


----------



## mikey

Guys, I highly recommend you call Ken and discuss grits with him if your intention is to grind a lathe tool from a square blank. When I queried him some years back, I think I recall him recommending 80 grit CBN for this purpose but don't hold me to that; I may not be remembering that right. Better to get it from the source. Ken is a good guy - you'll like him.

One of the guys in this thread also uses CBN wheels and showed his tool examples. See if you can find it.

Tim is right. CBN is intended for use on hardened steels and not for general grinding. If you plan to stick to wheels for tool grinding, having a separate grinder with your tool grinding wheels would be wise. Use your other grinder(s) for general use. If you go with a dedicated grinder, an 8" would give you less concavity on the tool face and would be a better choice vs 6".


----------



## tmenyc

Thanks, Mike, as always.  I will check with Ken about grit specifically for cutting HSS tools.  Thanks for confirming the rest.  
Fin, are you still in?
Tim


----------



## Aukai

If you could report back to, please.


----------



## tmenyc

Shall do!


----------



## finsruskw

tmenyc said:


> Thanks, Mike, as always. I will check with Ken about grit specifically for cutting HSS tools. Thanks for confirming the rest.
> Fin, are you still in?
> Tim



Having second thoughts Tim,
Watched his video and he said NOT to use this wheel for ANYTHING other than sharpening HSS cutting tools!!
Seeing now, as how I am probably going to have a lathe to rebuild,  I had better concentrate my funding in that department.

So I am going to settle for making a pattern set in mild steel  using  the patterns that arrived last last week.
Hope you understand, I'm afraid I jumped the gun in my over  exuberance  for this endeavor


----------



## tmenyc

Fin, yes, one of the important lessons of this board, certainly applied to me this past year, is that you need to do what's right for you at your pace.  I started from less than zero a year ago.  The more knowledgeable folks here will politely tell you when they strenuously disagree with a course of action you're contemplating but they won't be anything but considerate and helpful.  

I'm going to go for it; just not decided yet whether to go for 8" or 6".  I'll hang on to my coarse wheel in case I really need it, but have a 120 grit wheel I'll keep on the left side of the grinder for other jobs.  80 grit is the right level for cutting HSS tools from blanks; I was incorrect about the 180.
Ken sent me this article from their website, which explains it all pretty clearly.  My summary, which I've confirmed with him, is that CBN will work well on M2, M42, and M43; which covers the typical HSS blanks we find, plus MoMax and Latrobe Dynalite, although he didn't/wouldn't comment on any specific brands, which I understand.  It is not designed for tungsten-based tools like Rex and Carboloy. 

Tim


----------



## mikey

CBN should cut those tungsten bits, Tim. You just have to go slower because Tungsten is hard!


----------



## tmenyc

Even better!
Tim


----------



## finsruskw

Are there drawings/prints of these cutter bits available anywhere?
Something one could print and carry to the shop to stick on the wall.
Also, is there a sequence of operations that should be followed when grinding, i.e. front, sides, top etc?
I feel that a print would explain a lot about the grinding of these bits to get them in the ball park and up to bat for Mikey's mods.
I have a set of the models in hand and my angle gage should be in the mailbox tomorrow.


QUESTIONS
KInd of off topic here and maybe a newbie dumb ?? but
I have my 6" vise in tram to near .002. and checked with a last word DI, Is that acceptable for fly cutter work on aluminum or should a strive for closer?
The mill was leveled using a carpenter level, is that acceptable as well??
Thank you!


----------



## Z2V

Dave, look at page 4 of this thread. Mikey lays out what your asking starting on that page.


----------



## mcdanlj

finsruskw said:


> Are there drawings/prints of these cutter bits available anywhere?



I created models in OpenSCAD and put them on thingiverse but:

They demonstrated some ambiguity in the specification vs. the sequence of operations; the sequence of operations described does not, as I understand it, exactly create the angles as described in machinery's handbook. I sent a set of printed models to @mikey to review them to see whether they were a good representation of what he makes, but they arrived at a particularly busy time so I don't know whether he has had a chance to review them to see whether the angles modeled accurately represent what he describes to cut.
OpenSCAD doesn't have a feature for making prints.
Nevertheless, the models might help someone else make prints.


----------



## finsruskw

Z2V said:


> Dave, look at page 4 of this thread. Mikey lays out what your asking starting on that page.



Thanks, I'll look that up.
Now that I have the time (dead of winter here) and I have the mill set up, I'm really excited to learn about it's operation and get working on some type of project for it.


----------



## mikey

mcdanlj said:


> I created models in OpenSCAD and put them on thingiverse but:
> 
> They demonstrated some ambiguity in the specification vs. the sequence of operations; the sequence of operations described does not, as I understand it, exactly create the angles as described in machinery's handbook. I sent a set of printed models to @mikey to review them to see whether they were a good representation of what he makes, but they arrived at a particularly busy time so I don't know whether he has had a chance to review them to see whether the angles modeled accurately represent what he describes to cut.
> OpenSCAD doesn't have a feature for making prints.
> Nevertheless, the models might help someone else make prints.



I looked at the models back in April and this is what I thought:

_*Had a look at the models and here is what I found:*_


*Square tool: Side cutting edge angle is good. End cutting edge angle is 22 degrees instead of the 10 degrees that I prefer. Relief angles both 15 degrees, both rake angles 15 degrees. This tool looks very good except I would fix the end cutting edge angle.*
*Knife tool: Relief angles both 15 degrees. Side rake was 19 degrees and back rake was about 13.5 degrees. I normally make the side rake 15 degrees and the back rake about 10 degrees. Your will not hurt anything; might be better in some materials like aluminum.*
*Threading tool angles are all good.*
*Stainless tool: Side relief was 27 degrees, back rake was only 2 degrees. End cutting edge angle was 15.75 degrees. I think this tool would work better with more back rake and maybe a bit less side rake.*
*The aluminum tool was difficult to assess. The extreme back rake does make it look like a hook. I'll have to take a pic of mine but it is also quite hooked. The reason for that is that my belt slides to the side as I grind the rake angles due to the extreme back rake. Hard to explain but I now have some ceramic belts and will try to grind a new tool and show you that.*
_*Overall, impressive what the 3-D printer can do. Not sure if you can alter the angles but as long as folks understand what the angles are supposed to be, I see no reason to change the program much. *_


----------



## mcdanlj

Thanks @mikey! I lost track of where we got in DMs, sorry. My fault. I have now reviewed. I remembered some difficulty communicating about the precise definitions of the angles. I didn't want to be in any way obnoxious, but I was trying to ask clarifying questions to be sure I understood what references you were using for the angles, because if my understanding doesn't match yours, the math doesn't work and the models I create are misleading. It wasn't clear to me that we were interpreting Machinery's Handbook in the same way. (For example, I modeled the stainless tool with 25⁰ of side rake and 10⁰ of back rake, but it measured at 27⁰ and 2⁰ respectively, which makes me think I'm not understanding correctly, or that I had a problem printing...)

Also, you were thinking about cutting an aluminum tool (I presume from key stock) and sending it to me so that I can get that model right too.

I updated for the end cutting edge angle, so the version currently available uses an 80⁰ nose angle (the included angle of the tip) based on your feedback.

I should sign up for copies of the tools so that I can measure them and make sure my model is accurate. I had been waiting until I can build a 2x72 belt grinder, but that's still a ways out, so I'll DM @Z2V to sign up.


----------



## mikey

Life is nuts right now. I am getting to the forum or the shop an hour or so in between everything else and tool grinding is the last thing I can get to until life settles down. Not really complaining; I love my life but right now I have to take care of others. So I will get to the aluminum tool, the shear tool and the other things that I said I would do but it will have to wait ... sorry.

I do think looking at a set of model tools from Jeff is a good idea, though.


----------



## ch2co

Mike
Thank you again for all you are doing for this group. All us impatient lookie loos just need to remember that your time is yours. We can all sit back, have a cold beer or hot coffee and wait  for your expertise and knowledge to flow.
The Grumpy old guy


----------



## DavidR8

Yup, I think I can speak for all of us and say that we’re very grateful for all that you @mikey  and the other experienced folks here give to us newbies. Me being chief of them! 


Sent from my iPhone using Tapatalk


----------



## mikey

Thanks. For reasons I can't discuss, life has been unusually busy for me. It won't last forever and I do appreciate the support.


----------



## mcdanlj

mikey said:


> Not really complaining; I love my life but right now I have to take care of others.



Taking care of folks always comes first in my book! No pressure from me.

If anyone else on the thread has used the knowledge @mikey has shared here to make a different tool that worked well for some particular material, and you would like to share, if you are willing to write a description of what the tool was good for and send me a keystock copy, I am wiling to try to add it to the set of 3D models I have developed. Drop me a DM if that sounds interesting.


----------



## finsruskw

Got one done. Had a heck of a time wrapping my head around the mirrored angle bit but I think I have it down now.
Had to do the top on the bench grinder though.  Mikey's model on the left in all photos (as if you couldn't tell!!  )

Am I correct in assuming my copy done in HSS in a fly cutter, it will have to turn CCW??


----------



## ttabbal

finsruskw said:


> Got one done. Had a heck of a time wrapping my head around the mirrored angle bit but I think I have it down now.
> Had to do the top on the bench grinder though.  Mikey's model on the left in all photos (as if you couldn't tell!!  )
> 
> Am I correct in assuming my copy done in HSS in a fly cutter, it will have to turn CCW??



Good progress! For a fly cutter, I use a left hand square tool and standard rotation. It works great for me.


----------



## mikey

I agree, you're doing good! Do you even have a lathe yet?


----------



## finsruskw

ttabbal said:


> Good progress! For a fly cutter, I use a left hand square tool and standard rotation. It works great for me.


Standard being clock wise?
Will get around to it tomorrow hopefully
I only have 1 HSS blank though, hope I don't screw it up?


----------



## finsruskw

Ground a pair of threading bits today, also another fly cutter bit
Will give the knife tool a shot tomorrow..


----------



## Z2V

Looking good there. 
Yes, clockwise


----------



## ttabbal

finsruskw said:


> Standard being clock wise?
> Will get around to it tomorrow hopefully
> I only have 1 HSS blank though, hope I don't screw it up?



I just think of it as forward and reverse, but yes, clockwise.  

If you mess up you can usually adjust the grind a bit. Or grind it down and try again. I suggest some cheap HSS on ebay for general use. It's decent for practice and general use. I save my nicer blanks for my most common tools or tough material. Do a test run on keystock too. It's great for getting practice


----------



## finsruskw

Been using plain old hot roll for the samples.
So far, so good!


----------



## DavidR8

Just received notification that my 2x42 belt sander was delivered! Woohoo!


----------



## ch2co

DavidR8 said:


> Just received notification that my 2x42 belt sander was delivered! Woohoo!


What did you get? And from where?
Just a nosy old fart.


----------



## DavidR8

ch2co said:


> What did you get? And from where?
> Just a nosy old fart.



I bought a Dayton 2x42 belt and disk sander. 



			https://m.grainger.com/mobile/product/DAYTON-Belt-Disc-Sander-6Y945
		



Sent from my iPhone using Tapatalk


----------



## ch2co

DavidR8 said:


> I bought a Dayton 2x42 belt and disk sander.
> 
> 
> 
> https://m.grainger.com/mobile/product/DAYTON-Belt-Disc-Sander-6Y945
> 
> 
> 
> 
> Sent from my iPhone using Tapatalk


Let us know how it works out. Is it sturdy enough unlike the Harbour Freight and it’s ilk. Does the 1/3 hp motor have enough umph?


----------



## mikey

I have the Sears version of the grinder David has, complete with 1/3HP motor. It is on the weak side if you use Aluminum Oxide belts but if you commit to using ceramic belts, that thing will grind HSS tool bits. I know because I tried it and it worked fine. I also used a wax stick lubricant and that probably helped but it was able to grind a 10% cobalt HSS tool bit with no problem. If you've ground cobalt before then you know its a bit on the hard side, and 10% gets pretty hard. The ceramic belt went right through it.


----------



## mickri

This is the tool bit in my large boring bar.   Sorry for the poor picture.




 I did not grind this tool bit. All I have done is hone it.  It came with the lathe and was in the boring bar.  It cuts like a dream.  It is ground pretty much like a RH tool bit with a pretty good nose radius.  In use it cuts on the end of the tool bit.  Not the side.

I have been wondering why it cuts so good.  Any ideas on why it works so well?

I have been thinking about grinding a LH tool bit with similar angles to try out for normal turning towards the headstock.


----------



## mikey

The tool is cutting with the side cutting edge that is pointing slightly backwards. Imagine if you turned your square tool towards the tailstock so that the side cutting edge contacts the work. As you pulled the tool towards the chuck, the side cutting edge does all the cutting and trust me; the finish when a tool is used like this is superb. So, I'm not surprised the tool cuts but because the end of the tool will bottom before the cutting tool will, this can only be used in a through bore.


----------



## mickri

I should have taken the tool bit out of the boring bar so you could better see the shape of the tool bit.  It is small.   1/4" square by maybe 3/4" long  The tool bit is at a 45 degree angle to the boring bar.  Here is a rough sketch of the tool bit.




As you push the boring bar into the hole the front edge at the nose makes first contact.


----------



## mikey

Okay, I see now. It will still cut as I mentioned above. That grind is common on this type of tool but there are other variants. As long as it cuts, that's what counts.


----------



## fitterman1

Hi fellas, just lurking, haven't seen much mention of chipcutters and nose radii.


----------



## mikey

Do you mean chip breakers? What about nose radii would you like to discuss?


----------



## fitterman1

Yes, I call them chipcutters. Want to know how people form them, and how they size their nose radii.


----------



## mikey

I do not use chip breakers anymore. For me, they just aren't worth the time it takes to make them but others on this thread may have other opinions and I'll leave it to them to respond. 

As for nose radii, I prefer them small. Most of my tools have a 1/64" to 1/32" nose radius on them. I prefer to use back rake and the edges adjacent to the nose radius to enhance finishes so I don't need a big nose on the tool. 

What are your thoughts on nose radii, fitterman?


----------



## fitterman1

Same as yours, 99% of my tooling is carbide so I don't use a lot of hss.
Most tools I grind are form tools eg radius corner tool (int & ext) or a specific tool to get into a deeper corner than I could get into with an insert. I don't rough or finish with hss unless its a form tool.
Grinding of rakes are specific to the tool I'm making, generally I keep my side rakes to a minimum to give the nose more support underneath. I don't think excessive angles are necessary because my tool will be on center and so any rubbing of the work doesn't happen. This also minimizes the time spent grinding and wear and tear on wheels. Sometimes I'll grind a small 45 degree chamfer to clear the bore if its a smaller bore with a smallheaded form tool. All grinding I do is freehand and when it comes down to a radius on the nose, its done the same and then honed on a diamond plate to give it a nice sharp edge. Size would be in the vicinity of half to 3/4 mm, roughly the same as your sizes.
I have wheels in SiC, AO and diamond, grades hover around the 60 grit for the stone wheels to 80,100,150 for diamond. I have diamond plates upto a thousand grit for honing. I find a coarser wheel gets me there faster without too much heating. Used to use a belt sander for large drillbits (upto 2 1/2 inches) years ago, that was much faster than the grinder and I found it more accurate too.


----------



## fitterman1

Forgot about the chipbreakers, I have a couple tools with them only because I got them in a bundle. Personally I don't bother grinding them, just interested if others do.


----------



## Downunder Bob

I agree, I can't be bothered with chip breakers, I use a mix of HSS and inserts, some of the inserts have chip breakers, and so be it. None of my HSS have breakers I simply can't see the point. I have seen people spend hours trying to perfect a chip breaker, by which time the whole job could have been done, and they could be sitting down with a beer.

I also agree with Fitterman1 keeping relief angles to a minimum, especially on outside turning they're almost redundant, but do need them for internal work.

So far I have only ever used 60 grit AO and occasionally the Dremel for making a form tool, I don't have any diamond wheels or laps. I don't even have a decent bench grinder at the moment, only a small belt sander 1" belt and only 300W I do my roughing with an angle grinder then finish on the belt. I have bought a bench grinder, but have yet to set it up

My go to tool for HSS is the Eccentric tools Diamond tool holder so sharpening is relatively simple, I have a box of 3/8 HSS from my apprentice days, so far none of them have needed re-sharpening.


----------



## mikey

The great thing about HSS tools is that we can make whatever we want to do the job at hand. There is no right way or only way; as long as it works for you then that is what matters.


----------



## finsruskw

Finally got around to grinding a bit from ther on;y HSS blank I had for my fly cutter.
And I have to report I am amazed at the results.

My son gifted me a chunk/ingot of recycled aluminum that he smelts down out of cylinder heads, pistons and what not from scrap cars.
I had been looking at making a small parts fixture pallet for the mill but balked at the $45 price for a small piece of 1" x 6" plate at the local supplier.

Mounted it in the vise sitting on four 1/2" nuts to make in un-tippy and tight and went to work with an end mill to start with them switched to the fly cutter using the bit I had just ground. Smoothed what's going to be the bottom and cut 2 dado's in the edges then flipped it and clamped it in the vise.

I still have a ways to go as you can tell from the surface. It is at about 1-7/8" right now.

BTW, I still have the models and can send them to whomever whenever.


----------



## mikey

Nice!


----------



## DavidR8

Well done @finsruskw!


Sent from my iPhone using Tapatalk


----------



## mickri

My lathe came with several of those craftsman round boring bars where the tip is like an "L" on the end of the bar.  Never could master trying to grind one of those things.  Until today.  I drilled a hole one drill size smaller that the OD of the boring bar in a block of wood.  Then forced the boring bar into the hole.  It is a very tight fit and the boring bar doesn't move on its own.  Yet you can twist it to get it wherever you want.  Now I had something to hold onto and had no problem grinding the tip.


----------



## WobblyHand

Not sure where to post this, but it is a tool grinding question.  Moderators, please move this to the correct place, if I've posted here in error.

I want to make a spindle light for my drill press.  Got some circular LED rings that can coaxially go around the spindle.  (10 weeks shipping from China, eek!)  They mount with little tabs.  So bought a chunk of aluminum disk, 1/2" x 3.75" in diameter for the holder. It's too thick, but that's fixable!  There will be a 2.090" hole for the spindle (that's easy).  Then I'd like to cut a circular undercut slot, so the little tabs could grab on.  If nothing else, they'd be used to locate the rings while the epoxy is drying.

Not sure if I need to grind 2 tools or not.  The first to do the slot depth and a second to make the undercut.  Kind of like an "L".
Here are some pictures to show you what I mean.


These are the LED rings and the faced off aluminum.


Here are the little tabs I'd like to engage.  It's not much of an undercut.

Lastly, this is what I was thinking I might grind for tools, and a sketch of what I was thinking.


Tool 1, would cut the vertical slot in the plate.  ("The vertical part of the L".)  It needs to be about 0.15" deep.  Tool 1 might be something similar to a parting blade, but I have no idea if that makes sense.  Tool 2, would cut the horizontal part of the "L".  The horizontal part of the L only needs to be 0.05" x 0.05".  That should be sufficient for the tab to lock.

Is there a simpler tool(s) that might work?  I've got lots of 8mm square HSS tooling I can play with.  What should the profile or angles on the tool look like?  I'm a little unclear on this.  Never tried to make custom tooling before.  The plate is 6061.


----------



## mikey

Yup, I think you need two tools. Tool #1 to allow Tool #2 to access to cut the Ell. Tool #1 will need to cut a wide enough groove to allow the entire width of Tool #2 to get in there. 

Tool #1 will essentially be a parting tool and only needs 7-10 degrees of side relief on both sides. Tool #2 can use the same side relief per side but it also needs front relief. I am thinking maybe 10 degree at least, in a rounded profile.

Both tools would have zero rake and sharp corners.

Dunno', guys, what do you all think?


----------



## DavidR8

Definitely a two tool job. 
I’m far from an expert but is the anything special needed because it’s aluminum?


Sent from my iPhone using Tapatalk


----------



## WobblyHand

mikey said:


> Tool #1 will essentially be a parting tool and only needs 7-10 degrees of side relief on both sides. Tool #2 can use the same side relief per side but it also needs front relief. I am thinking maybe 10 degree at least, in a rounded profile.


Thanks on the guide for the angles.  A little hazy on what you mean by a rounded profile.  Which face is rounded?  Top, side1, RHS, LHS, end?  I think you mean the top cutting edge is rounded for the Ell?  


Going to have fun making this 2nd tool.  I can hog some stuff out with the belt sander.  After that, the only thing I have that might work is a dremel or a die grinder.  Have grinding stones and small diamond bits for it.  Going to have to clamp that bad boy down and sort of do this by eye. Safety goggles for sure...  I'm diving in...


----------



## mikey

The part touching the wall being cut must be curved to avoid contact. Only the top cutting edge should touch.


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## WobblyHand

So making this tool #2 is kind of hard with what I have.  Really need to NOT hand hold the dremel!  That being said, this is what I have so far.  Having a difficult time getting the right shape.  Really want a sharp edge rather than a rounded one.  In other words, the inside corner needs to be sharper, or the little tab won't engage.  Tool #2 looks like a "P" now.  I'd like the angle the the rounded part intersects with the vertical part to be a lot sharper and closer to 90 degrees.  I used the band sander to narrow things down. The in cut was made with some diamond bits and a lot of fumbling.  The cheapo diamond disks did not have sharp square edges.
Tool #2 is on the left, tool #1 on the right.  Have to be careful when I put #2 on the lathe to make sure the undercut is on the correct side.  Just checking... the tabs are on the inner side, luck that it's on the correct side!



Not sure how to hone tool#2 with the 2"x3" diamond cards that I have.  Definitely testing my abilities   Still, I'm a bit closer.


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## mikey

An alternative is to use an internal grooving tool but its more fun to grind it.


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## ddickey

This one is only $12 bucks.


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## brino

@WobblyHand

Don't you want the mirror image of that P-shaped bit?



I guess it depends on how your holding the tool (front of centre/back of centre and upside down or not) and whether the lathe is running forward or reverse....

-brino


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## WobblyHand

Both of them are much nicer, with sharper corners.  Having used one of their boring bars before, I'd be inclined to get one next time. For now, I'll keep plugging away at this.  I'm half thinking that if I run the edge of the diamond card along the belt sander, maybe I can get in a little closer and get a squarer edge.  The corners and edges are "rounded for safety".

The linked carbide tools looks good, I think I'll buy it just because.  Some diamond needle files might help me shape this HSS tool better.  Hope to find some at a reasonable price, and not have to wait 6-8 weeks for them.


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## WobblyHand

brino said:


> @WobblyHand
> 
> Don't you want the mirror image of that P-shaped bit?
> View attachment 320762
> 
> 
> I guess it depends on how your holding the tool (front of centre/back of centre and upside down or not) and whether the lathe is running forward or reverse....
> 
> -brino


I think it will work out ok.  The undercut for the slots faces the center of the disk because the little tabs on the LED rings are on the inner radius.  If not, I'll find a way, upside down, or whatever.


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## brino

WobblyHand said:


> the little tabs on the LED rings are on the inner radius



Ah I see, you are correct!
-brino


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## GunsOfNavarone

I'll tell you, I really only use carbide b/c of the fear of needing to make my own HSS cutters and or sharpening them, I'd love to see a video of you in action, along with some of your thoughts on why you angle things the way you end up grinding them...the thought process.


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## WobblyHand

GunsOfNavarone said:


> I'll tell you, I really only use carbide b/c of the fear of needing to make my own HSS cutters and or sharpening them, I'd love to see a video of you in action, along with some of your thoughts on why you angle things the way you end up grinding them...the thought process.


Umm, I have to laugh.  Making the video, would be hard for me.  Making these tools wasn't _that_ hard.  It's more a willingness to try and fail.  The worst that could happen is one tosses out a piece or two of tool steel.  

For the hogging out I used my belt sander.  The ceramic belts really remove material quickly.  For the shaping, I used two burrs out of a Harbor Freight Diamond Rotary Point Set.  Spent a whopping $20 on the diamond bits.  After that it's just sculpting out the metal that doesn't belong.  Go slow - be safe.  Think about what could go wrong if something broke suddenly.  Wear safety glasses, and have at it.  

To be honest, I was dreading trying this.  But I plowed ahead.  It was a little awkward for me, since I didn't know what I was doing, but in the end, it wasn't hard.  This is what I like about being a hobby machinist - it forces you to think and be creative, so you can make what you previously thought was impossible.

So just try it!  And post up your pictures!


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## GunsOfNavarone

I mean @mikey  I know he’s kinda a genius around here when it comes to shaping HSS. I saw someone here’s video of a tool he made for a shaper...I was pretty impressed by how it improved DOC, speed & finish. I’ve seen the video of the final product, but never how to get there. I’m sure there are vids out there, but when you can’t talk with the person making the video, you have no way to troubleshoot or ask questions.


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## WobblyHand

@mikey has a knack for explaining things.  He's very patient with us beginners.  If you follow his instructions for grinding the 3 tools (buried in the early part of this humongous thread), you, too, can make some tools.  That's how you can start.  It's not that hard, really. There is a document that Mikey wrote (in this thread) which tells you step by step what to do.  It really works. 

I don't have a shop that has a lot of stuff, it's really quite minimal.  I've never ground tooling before.  But I read the document and thought, hey, I can _try_ that!  (At that point, I didn't think I could actually do it.)  In all seriousness, it's just you, a grinder and a piece of tool steel.  You can try.  The result might not be perfect, but that's ok.  It could be ugly, it doesn't matter.  It is a start, and an important step.

Then show us what you have.  @mikey and others can guide you and refine your technique.  The journey to tool nirvana starts with a single step .  Not laughing at you, just my horrible allusion.


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## mikey

Thanks for the kind words, guys. If you look at the pics in this thread and imagine my hands going left to right repeatedly, that is essentially how I grind a tool. Not a whole lot to the grinding thing. Page 4 of this thread will show you how to get the shapes you need for the three model tools discussed here, and you can PM @Z2V to get on the list to see and handle the model tools.

I do agree that a video would be nice to do one day, although as I said, it would just be me going back and forth.

As to the thought process behind the tool angles, that has been covered in this thread. Somewhere in this thread are some pdf files of all the stuff I've written on HSS tool geometry, too. I offered to do a group brainstorm thing where we would go through the thought process for grinding a tool for a specific material but it never took off; I figured the guys just weren't interested in it.

Guns, if you read this thread (yeah, I know its a monster), most of what is in my head is also in here. What is not here is how I think. That tool you referred to was something @Ulma Doctor and I brainstormed together to see if we could come up with a tool for his shaper. That was fun and it seems to work pretty okay but the thinking part is something we did in a PM. We can share that if the Doc chooses to do so.

Oh, and just to be clear, I'm no genius. All I did was not buy into the belief that the standard tool angles found in a tool table were gospel. Then I took the time to grind hundreds of test tools to see what worked and what didn't work. To be very honest, much of the motivation for learning this tool grinding stuff was so that I could make my live center. I needed to grind a tool that could reliably take a tenth of material off of 1144 steel and with control to make the arbor for that live center. You see, it isn't hard to rough stuff. Inserts and brazed carbide or even any old HSS tool can rough, but not every tool can take a micro cut with control. That takes an understanding of tool geometry so that is what I set out to do and it worked out pretty well.

Paul Thede, the owner of Race Tech Suspensions once said, *"The best you've ridden is the best you know."* If all you've ever used are inserted carbide tools then its natural to think that those tools are all you'll ever need. Little do you know that there is a whole lot more to precision turning than those tools will allow. I own carbide tools, too, but I don't use them often because HSS works better for me in most cases. The thing is, I have the option of choosing which tool to use; many do not.

I encourage you to give tool grinding a try. It isn't for everyone but if you own a smallish lathe or if you need to turn with great precision from time to time then it is a skill well worth learning. If I can help, I am here.


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## WobblyHand




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## Ulma Doctor

@mikey , you have my blessing to use any part of our communications to further the transfer of knowledge to the peanut gallery!!!


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## ttabbal

Ulma Doctor said:


> the peanut gallery!!!



Hey! I resemble that remark!!  

Honestly all, I started from zero learning this stuff. If I can grind good tools, you can too. Get and read the Book of Mikey, and grind some cheap keystock to get a feel for it. I enjoy making my tools. I really enjoy dialing in a tiny cut and watching the metal dust just flake off.


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## benmychree

And a round nose tool!  My machine shop teacher in high school showed us how to grind the various tools, gave each of us pieces of key stock and we went to work on our tools, when we could show him a properly ground tool, he gave us all brand new tool bits to grind, and all of us kept them for the school term.


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## tmenyc

Yes, I stalled at it partway through, after a few failed square tools, until Mikey got to me in a PM.  Since then I've got it done, and actually like making them, it's fun, although a bit slow on my 6" Dewalt grinder.  I now have LH and RH square tools, a RH square with a really small NR, and a 60 deg threading tool I use all the time.  Absolutely worth doing, and creates a whole different perspective on turning, when you made the tool.
Tim


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## WobblyHand

Back to the inverted "el" tool.  I tried it out, documented in the LED spindle light thread, and found it was rubbing more than it was cutting.  Rarely made chips, more like grey dust.  Sometimes when adding oil, it would start to cut.  The tool needed a lot of pressure to work.  It was a balancing act between applying pressure and stalling.  It made the workpiece smoking hot, eventually boiling off oil!  Even the chuck was hot!  It seems that I didn't hone the cutting edge right up to the top of the tool.


Guessing that little flat edge up near the top of the triangle is the culprit, right?  So I touched the belt sander to this face.  (100 grit ceramic, about 14.3 degree.)  I really couldn't even tell the sander was cutting, that's how light a touch.  It removed just enough material on the triangle to remove the top facet.  A lot more honing later, (325, 600, 1200 grit) I had this:


Is this good enough, or is more polishing is needed?  There's a hint of a bright spot on the top right corner, but I'm having a difficult time removing it.  I think it's a little less than 0.010".  That face is about 0.100" wide.  My patience is being tested, as honing seems to take forever.  After thinking about it some, I took some of the tiny flat spot out by flattening the right hand side triangle edge, like one does on a single point threading tool.  Still can see it at 8X.

My diamond cards are loading up with grey HSS dust and it's getting hard to get that nice polished face.  (Get streaks, or tiny gouges.)  I tried wiping the cards with an alcohol wipe, but the wipe fibers then catch on the stone.  I then use a kimwipe to get some of the fibers off.  There's still stuff on the cards.  Is there an easier way to clean the diamond honing cards?


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## WobblyHand

mikey said:


> An alternative is to use an internal grooving tool but its more fun to grind it.


Grinding is fun.  You can see a tool taking shape.  Honing by hand takes far too long to be fun (at least for me).  It's hard to maintain the flat faces, especially if they are very small.  Is there a poor man's diamond grinder that could be used for tool bit making?  Would a Noga indicator holder be stiff enough to hold the tool and maintain a clean face?  Or is something more robust needed?


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## mikey

WobblyHand said:


> ... it was rubbing more than it was cutting. The tool needed a lot of pressure to work.



In order to cut, the edge must have adequate relief under the cutting edge. From the end of the tool, the profile must be shaped something like this. The arrow is pointing to where you have to have relief, a clearance angle. Only the cutting edge must touch the work piece.







WobblyHand said:


> Is there an easier way to clean the diamond honing cards?



Some scouring cleanser, like Comet or Ajax, works well. Scrub with cleanser and a brush and do this often.


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## WobblyHand

I can report that the new tool works!  It has about a 14 degree relief.  It cuts chips!  Getting rid of the flat spot fixed it.  Just touched the belt sander lightly and it cut the tool down enough to eliminate the flat spot.  Lots of honing after that.  The workpiece didn't get hot, and really didn't need much if any cutting oil.


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## WobblyHand

One advantage of grinding your own - you don't have to wait for tooling.  You know that grooving tool you guys recommended?  I bought that on the 13th.  You know, just because.  I was wondering where it was.  Just looked it up.  It's now scheduled to be delivered on May 15th!  Yeah, it's great to be able to grind your own.  Someday I'll use that magic grooving tool.  But I don't have to wait for it, because I made my own, and the job is already done.


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## mikey

WobblyHand said:


> Yeah, it's great to be able to grind your own.



Yup. Imagine all the hobby guys out there who cannot ...


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## WobblyHand

I don't see why they can't.  If old Wobbly Hand fumble fingers can grind one, *anyone* can.  All done by eye and a sharpy marker on metal, just like your instructions said.  That, and a wee bit of tenacity to see things through.


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## mikey

I'm just guessing but I suspect the vast majority of hobby machinists use carbide lathe tools. Its only been since this thread came into existence that this has started to change, at least on this forum. Out there, in non-HM land, carbide rules. Tool geometry is confusing and understanding what you're grinding and why you're grinding it that way is not easy. It is much simpler to just buy a cheap insert on ebay and go with that; hence, the majority of carbide users. I don't blame them, either. 

Then I've seen comments like, "I tried HSS and it didn't work for me so I went back to carbide". This leads us to believe that any HSS tool will work the same as any other HSS tool. As we know, nothing could be farther from the truth. A good HSS tool is good because the geometry is right, not because of the material the tool is made from. 

I sound like a broken record but the best lathe tool to use is the one you need. For some things, carbide is definitely the best choice. For other things, HSS is better. You have to know how to use both and must know how to grind a good HSS tool in order to have the choice.


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## craniac

mikey said:


> I sound like a broken record but the best lathe tool to use is the one you need. For some things, carbide is definitely the best choice. For other things, HSS is better. You have to know how to use both and must know how to grind a good HSS tool in order to have the choice.



Mikey,

Would this be the place to elaborate on the appropriate uses for carbide and HSS respectively?

I've been studying up on HSS grinding because I have 10" atlas lathe and a 12" under repair and understood that carbide is best used on machines capable of exerting more force than these small Atlas types. Also the PO of my first lathe laid a bunch of HSS blanks on me. Subsequently I bought a lot  of machine tools from a chap whose father and grandfather owned which included a bunch of ground tools. So I've been gearing up to grind my own by modifying a belt grinder (following your articles) as well as simply honing my old pre-ground tools and experimenting.

I also have a small insert tool holder with a handful of inserts that I sometimes use. It seems like understanding the vast array of inserts is almost as much work as grinding HSS. Not to mention the expense.

Maybe this has been discussed before in this voluminous thread, which I have read but maybe not retained.

Tim


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## ttabbal

For smaller machines, I think carbide is great for hard materials. I have some random stuff here that's hard enough to kill the edge on my HSS bits really quickly. Carbide will chew it up nicely. You can't just drop in carbide any more than you can drop in HSS. Carbide inserts have loads of types just like we have loads of grinds. And there are some things to watch for, like needing some depth of cut on carbide or it rubs. Where you can take a couple tenths off with sharp HSS tools. 

When you are new and just starting to look at options though, it's easy to see pre-formed inserts and think you can just grab and go though. And you kind of can, but you will get better results if you know how to use them as they are designed. 

For job shops where time is money, I get them using all carbide. Being able to break a tip and just drop a new insert in means more productivity and thus more profit. As a hobby guy, I'm ok having a couple HSS tools so I can swap if I manage to break a tip or dull one going too fast etc., then just grind them to spec later. Experience helps a lot, I break a lot less often now.  

And you sometimes need a weird shape, like the grooving tool above. It is nice not to have to wait for shipping for them.


----------



## mikey

ttabbal said:


> For smaller machines, I think carbide is great for hard materials. I have some random stuff here that's hard enough to kill the edge on my HSS bits really quickly. Carbide will chew it up nicely. You can't just drop in carbide any more than you can drop in HSS. Carbide inserts have loads of types just like we have loads of grinds. And there are some things to watch for, like needing some depth of cut on carbide or it rubs. Where you can take a couple tenths off with sharp HSS tools.
> 
> When you are new and just starting to look at options though, it's easy to see pre-formed inserts and think you can just grab and go though. And you kind of can, but you will get better results if you know how to use them as they are designed.
> 
> For job shops where time is money, I get them using all carbide. Being able to break a tip and just drop a new insert in means more productivity and thus more profit. As a hobby guy, I'm ok having a couple HSS tools so I can swap if I manage to break a tip or dull one going too fast etc., then just grind them to spec later. Experience helps a lot, I break a lot less often now.
> 
> And you sometimes need a weird shape, like the grooving tool above. It is nice not to have to wait for shipping for them.



An excellent response, Sir!


----------



## mikey

craniac said:


> Would this be the place to elaborate on the appropriate uses for carbide and HSS respectively?



Morning, Tim. I'll just add on to ttabbal's response.

The first thing I wanted to point out is that your lathes were meant for HSS, not carbide. Unless you have a high speed motor on them, HSS would be the first choice because carbide needs speed to cut well. I know you're aware of this but some new guy following this might not. 

In addition to speed, carbide also benefits from rigidity and power, something a small lathe just doesn't have. Given these limitations, it might seem that carbide won't work but it will; you just need to choose carefully. This essentially means you should stick with positive rake tooling and keep nose radii small; both of these things keep cutting forces lower. You should also try to buy finishing inserts; these have very little space between the cutting edge and the chip breaker, which also lowers cutting forces. Whenever possible, use inserts with ground edges that are sharp; again, this reduces cutting forces. This narrows the field but still leaves thousands of choices so let me boil it down for you a little. 

I have tried what seems like a lot of carbide tool holders and insert types. It took a long time to figure out what I told you above. If I had to choose a single tool holder and insert designation today, I would definitely recommend the SCLCX tool holders. These tool holders take CCMT and CCGT positive rake inserts and hold them at a 5 degree cant that allows the tool to both face and turn with the tool shank held perpendicular to the work piece. I would choose the smaller tool holder when given the choice, purely because the available nose radii include smaller radii with smaller tools. For me and my 11" lathe, 3/8" tool holders work best and I can get nose radii down to 0.008", which allows me to make smaller cuts for improved accuracy. 

Inserts abound for these tool holders but assuming you buy a 3/8" tool holder, I would get CCMT and CCGT 25.205 inserts (the SCLCX tool holder will accept both types of inserts) and only go with larger nose radii if you have to. When buying CCGT inserts, look for the AK grade of inserts. These have a sharp ground edge that is uncoated and polished so they are very sharp. CCGT inserts are usually used with aluminum but they will also cut most other materials and are more useful than many hobby guys realize. 

The other thing to know is that inserts are meant to be with the tool holder perpendicular to the work. However, they often work better when we turn the tool holder to positions that allow different edges to cut; this especially helps with finishes. You should play with this to see what works for you. If you watch videos of a CNC lathe with live tooling, you will see that the insert changes position to suit the contours of the part being cut and this also works for us; we just have to understand which edge should be in play for a given need. Play with this when you can. 

There is a lot more to using inserts than I can put in this response. The minimum and maximum depths of cuts, speed and power requirements, impact of nose radii on accuracy and so on would take a book, one I'm not qualified to write. I have opinions on this subject that I sort of put in my Boring Primer but even that is not an authoritative work. Maybe one of the other guys might want to give it a shot.

Okay, time for the bottom line: For most work on your lathes, using the common hobby guy materials, I would try HSS first. If the tool does not cut well or dulls quickly, change to carbide and use as much speed as the diameter of the part allows. I rarely cut unknown metals so for me, 90% of my work is done with HSS. I can rough without problems and take very fine cuts to come in on size so HSS works best for me. I switch to carbide when cutting harder materials like stainless or medium carbon steels or tool steels. At times, I will rough tool steels with carbide and finish them with HSS; O-1 in particular benefits from this approach and will achieve a mirror finish at high speeds with a sharp HSS tool.

You have to play with this stuff to sort it out for yourself and your machines. That's what makes tooling choices fun. I hope this helps but if you have specific questions, lay them out and we'll try to be more helpful.


----------



## ttabbal

mikey said:


> An excellent response, Sir!



Thanks! I'm starting to understand some of this stuff. It makes me realize how much I don't know, but it's a start.


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## craniac

I appreciate your responses and the digression into carbide inserts. A chap offering HSS blanks and endmills on CL generously turned me on to a SCLCR tool holder and some Kennametal CCMT inserts. They work good on stainless and I will use these as you suggest for roughing O-1 on an upcoming project.

What I find critical to grinding my own is repeatable tool rests and jigs, which is why the belt grinder treatise was so valuable to me. Folks that can hand grind have my respect, but I'll never get enough practice on a consistent basis to achieve, and more importantly, retain that skill level. Sometimes I get very little time to do much more than sniff around the shop (well the shop dog does the bulk of the sniffing). 

Tim


----------



## mikey

Keep us posted, Tim. If you show your tools, we can help guide you if that proves to be necessary. Good tools make lathe work a real pleasure and we'll do what we can go help you.


----------



## DavidR8

So I'd like to grind a form tool to cut an outside radius on the lathe. I have absolutely no idea how I'd go about grinding the radius. 
I could use a corner rounding end mill but I'm really curious how I'd grind an HSS bit to form an outside radius.


----------



## mikey

Classic way is to dress the corner of a grinding stone to the radius you need and slowly push the blank into that corner to form the radius. I've done it by grinding some relief under the edge and  shaped what I needed with a Dremel stone. Or you can use a file if you have only one to do. What I normally do is just use a graver - way faster, cleaner, easier for me.


----------



## craniac

Here's my newest tool, my initial effort was about 6 mos back. I've been tweaking the grinder set up and it's getting better. Waiting for a diamond hone to arrive, so this tools is still pretty rough. I think it can be better and we'll see how it works on the lathe.







I think these are the first pics I've put on this forum. Will have to work on my presentation in future.

Tim


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## mikey

Nice job on the grinding! Hone that puppy up and let us know how it works for you.


----------



## Aukai

I took the time to make a right hand tool today.


----------



## Aukai

Damn thing didn't post the other pics


----------



## mikey

Looking good, Mike! How does it cut?


----------



## Aukai

12L14 .350 DOC so far, I'll get a picture.


----------



## Aukai

Here is the pic, when I went back the bit had some weldment on the lead edge, how do you get away from that, lube?




Changed the lead angle looks like a better finish.


----------



## mikey

A 0.350" radial depth of cut is a good cut in mild steel, Mike. That's almost 3/4" off the diameter. Good job on the tool!

The improved finish in the second cut is due to engagement of the end cutting edge. Remember, the side cutting edge removes material but the end cutting edge provides the finish. As you change your lead angle towards the chuck, more of the end cutting edge engages and the finish improves. This is why it is more accurate to keep nose radii small to reduce deflection from radial forces and involve your end cutting edge more to improve finishes.


----------



## mikey

Aukai said:


> Here is the pic, when I went back the bit had some weldment on the lead edge, how do you get away from that, lube?



Forgot to respond to your question re the built up edge (weldment on the tip). This suggests that temps got high at the point of cut. Normally, this is not an issue with steels and some lube would help prevent it. You can also reduce speed a bit and this will reduce temps at the point of cut. The other thing that helps is to increase side and back rake a little bit, maybe 2-3 degrees more. This will increase chip flow and thin the chip at the same time, resulting in reduced cutting temperatures. Lastly, a BUE can be due to a overly large nose radius so I suggest you add a bit more side and back rake and keep the nose radius small, then use some lube and I bet a BUE will no longer be an issue in steel.


----------



## Aukai

Thank you, I had to resharpen the bit , my first try had a small nose radius, and the finish was horrible. after resharpening the pictures is what I got. I'll look at the bit tomorrow again.


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## Aukai

I have a blank of T5 coming, what nose geometry for cast iron would you put on it? This can move if needed.....


----------



## mikey

I'm not familiar with T5 cast iron, Mike. What is your source and do you have any info on its machining properties? 

There are four types of cast iron - gray, white, ductile and malleable. Most of the bar stock we see in a hobby shop is gray or ductile, with ductile being the most machining-friendly due to the ferrite and silicon content. I am not sure where T5 falls, Mike, and without knowing what it is, it is difficult to make a recommendation.

Quite often, we run into a cast iron of unknown type and this especially true when a hobby guy is trying to do something on the cheap. We know nothing of its composition, especially the carbide content, and then we wonder why we can't cut it. Some cast irons have a lot of pearlite/carbide in it and it will eat up HSS and some carbide tooling. In this case, it is best to pull it out of the lathe and dump it unless you're rich and can afford to experiment with inserts.

So, you need to find out what that T5 stuff is and we can try to go from there. An alternative is to find some Durabar ductile iron; you will really like turning that stuff. The last time I had some Durabar, I used a Square tool at low speed and it cut well with a nice finish.


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## ttabbal

Could T5 be the HSS type? I used something like that for cast iron and I was happy with the finish. I believe it was a 10 degree square tool.


----------



## DavidR8

ASTM T5 Tool Steel | 1.3265 | S18-1-2-10 | SKH4 | BT5
					

ASTM T5 Tool Steel is one of tungsten high-speed tool steel. It belongs to ASTM A600, together with T1, T2, T4 Tool Steel etc. They are also in T group in ASTM A600 standard. AISI T5 high speed steel contains Cobalt with range 7.0~9.5%. AISI T5 steel has better high temperature performance...




					www.astmsteel.com


----------



## mikey

Okay, I might have misinterpreted the post. T5 HSS grinds like M42 cobalt HSS - takes more pressure to grind it.

Find out which kind of cast iron you have, Mike. For light cuts at low speeds a Square tool will work.


----------



## Aukai

It will be for the cast iron backing plates, the new one coming is fine grain, or something like that. The bit is a Rex supercut which it T5

*T5 typical analysis (%): C 0.8; W 18.5; Cr 4.0; V 1.75; Co 8.0; Mo 0.8 – the ultimate in HSS for heavy duty cutting. Has a combination of red hardness and toughness that results in outstanding performance. Recommended for heavy duty lathe, planer and boring tools. Especially adapted for cutting hard, gritty material such as cast iron or steel, also heat treated alloy steels. Best used in tools that are well-supported and not subject to excessive shock or chattering. Cutting speeds can be about 25% faster than T1 with higher tool life.*


----------



## mikey

Cast iron backing plates can really vary in their quality, especially if the plate is from China. They can have hard spots and sand and who knows what else is in there. You should be able to turn it just fine with your T5 bit. Again, I would try a Square Tool geometry and see how it works for you. I suggest a nose radius somewhere between 1/64" - 1/32" to hopefully enhance the finish. Cast iron tends to crumble and a bigger nose radius might help.

Keep you speeds low, like 25 sfm and use a lowish feed rate. Do NOT use lube or coolant.

Cover your lathe, Mike, and don't forget to plug up the spindle bore so you don't send dust into your gear train in back.


----------



## Aukai

Will do, thank you. It's a South bend from Grizzly, and my previously not finished one for the Samchully chuck.


----------



## mikey

I remember having a bit ground specifically for cast iron but I don't know what happened to it. The last plate I cut was done with a Square tool and it worked fine for me. It helps to keep the tool sharp and you may need to touch up the edge at some point. You'll know it needs attention if it starts singing to you.


----------



## Aukai

Like a Thomson bar?


----------



## mikey

I said singing, not crying!


----------



## Aukai

ROTFL, at least I gave it the good old Collage try, and saw some amazing small machine reactions. I still do not know where a .010 deflection comes from on a facing cut that doesn't cut


----------



## Aukai

I would like to use a form tool to make a round groove, this is the basic shape so far, what other geometries does it need?


----------



## finsruskw

I'm still sitting on the models if anyone wants them!
They are in Iowa.


----------



## mikey

Looks good to me, Mike, except the top needs to be honed a bit more. See that bright edge along the rim? That means the relief angles underneath and the top surface are not making a clean intersection. Just hone it until that bright edge is gone and it will be sharp.

Remember that a form tool has a huge area of engagement so you have to run the lathe slower and feed carefully. By that, I mean you need to run really slow and make sure you feed fast enough to keep the tool cutting constantly. As you go deeper, cutting forces increase dramatically because more of the edge in engaged and you may need to slow down even more. Much depends on what you're cutting into but if you get the speed and feed right, it should go okay.


----------



## mikey

finsruskw said:


> I'm still sitting on the models if anyone wants them!
> They are in Iowa.



If no takers in a week or so, please contact Jeff to arrange to return them to him. Thanks!


----------



## benmychree

Depending on what tool holder is used, the front clearance looks quite excessive, this could weaken the cutting edge and also cause it to hog in.


----------



## Gaffer

finsruskw said:


> I'm still sitting on the models if anyone wants them!
> They are in Iowa.



I would love to borrow them.


----------



## Aukai

The clearance angle is 15*, I'll sharpen it up some more. I'm putting a shallow groove in a bending die to keep the bar from wondering. This is a 3" die, I need the groove in a 5"


----------



## ddickey

How wide and deep is the groove?
What size tool is that?


----------



## Aukai

1/2" tool 1/4" radius, I don't have an actual depth, about there is will do it.


----------



## ddickey

I was going to say maybe some side relief but if it's s short depth maybe it wouldn't matter. What's the size of the bar or rod?


----------



## thomas s

Nice job Aukai


----------



## Aukai

Thank you, the bar/rod is 1/2"


----------



## Z2V

finsruskw said:


> I'm still sitting on the models if anyone wants them!
> They are in Iowa.



If you don’t mind holding on to them until another member requests them. I’ll pass the contact info to you at that time.

Thanks
Jeff
Z2V


----------



## finsruskw

Jeff
See post 1261 above
Gaffer would like to get them next

Dave S.


----------



## Gaffer

Z2V said:


> If you don’t mind holding on to them until another member requests them. I’ll pass the contact info to you at that time.
> 
> Thanks
> Jeff
> Z2V



I’m good with that. Thank you. 


Sent from my iPhone using Tapatalk


----------



## Z2V

finsruskw said:


> Jeff
> See post 1261 above
> Gaffer would like to get them next
> 
> Dave S.



Good deal I didn’t see that.


----------



## Z2V

Gaffer said:


> I’m good with that. Thank you.
> 
> 
> Sent from my iPhone using Tapatalk



If you will PM me your contact I’ll pass it to @finsruskw and get them coming your way


----------



## Gaffer

Thanks, Z2V. He and I already worked it out.


----------



## Z2V

Ok


----------



## Gaffer

finsruskw said:


> I'm still sitting on the models if anyone wants them!
> They are in Iowa.


I received the models and look forward to learning from and replicating them. I'm posting this to say thanks, and so you know that I'll have them for the next person wanting them.


----------



## Z2V

Thanks @Gaffer for taking over the distribution of these models


----------



## mikey

Gaffer said:


> I received the models and look forward to learning from and replicating them. I'm posting this to say thanks, and so you know that I'll have them for the next person wanting them.



Show us your tools after you grind them, Gaffer.
 We'd love to see them.


----------



## Karl A

This is my first post in this thread. I am moving toward grinding my own tools.

Today, I received a Bucktool Combo 2" x 42" Belt Sander 6" Bench Grinder, Knife Sharpener BG2600 from Amazon.com. $200 + sales tax.

I wanted the combination of wire wheel and belt sander on a bench grinder. That's why I purchased this version instead of the Dayton or the Palmgren, which have a disc sander and a belt sander. 

Karl


----------



## ACHiPo

Karl A said:


> This is my first post in this thread. I am moving toward grinding my own tools.
> 
> Today, I received a Bucktool Combo 2" x 42" Belt Sander 6" Bench Grinder, Knife Sharpener BG2600 from Amazon.com. $200 + sales tax.
> 
> I wanted the combination of wire wheel and belt sander on a bench grinder. That's why I purchased this version instead of the Dayton or the Palmgren, which have a disc sander and a belt sander.
> 
> Karl
> View attachment 334724


Let us know what you think. That looks like a pretty good machine.  I saw a write up/video of the Grizzly industrial 8" grinder (I know, a totally different beast), but was pretty impressed, especially with the guards.


----------



## mikey

That is a nice machine, Karl. If I may, look into putting a ceramic glass platen on it; a 2x8 or 2x9 is good (buy two; use one and keep one for a back up). You can find them here. Let us know if you need details on how to attach it to your platen. I prefer to replace the stock platen with a piece of low carbon precision ground steel or a piece of O-1 precision ground steel attached to the chassis with a piece of angle iron. The reason for using ground stock is that it is flat and will allow the platen to be epoxied on solidly. Just my preference.

This is THE most important upgrade you can do for a belt sander. The second is a solid, adjustable tool rest.


----------



## Janderso

DavidR8 said:


> I bought a Dayton 2x42 belt and disk sander.
> 
> 
> 
> https://m.grainger.com/mobile/product/DAYTON-Belt-Disc-Sander-6Y945
> 
> 
> 
> 
> Sent from my iPhone using Tapatalk


I know, old thread.
David 
What do you do with the disc?
I bought the Kalamazoo but no disc.
Just curious.
Jeff


----------



## DavidR8

Janderso said:


> I know, old thread.
> David
> What do you do with the disc?
> I bought the Kalamazoo but no disc.
> Just curious.
> Jeff



Honestly I don’t use it and would prefer to have a wheel on that end.
That said I might see if I can adapt a diamond cup wheel so that I can hone carbide

Just last weekend I bought a 6” grinder from a wood turner so it already has high quality wheels because he used it to sharpen HSS wood lathe tools.
One wheel might get swapped for a wire wheel.


Sent from my iPhone using Tapatalk


----------



## finsruskw

I just checked and those are on sale now at Grainger thru 9/28/20


----------



## Karl A

ACHiPo said:


> Let us know what you think. That looks like a pretty good machine.  I saw a write up/video of the Grizzly industrial 8" grinder (I know, a totally different beast), but was pretty impressed, especially with the guards.


I expect that the machine will be adequate for my purposes after modifications. My purposes are grinding lathe tools and general light-duty grinding of metal and plastic using the belt sander, and removing rust, dirt and paint from tools and other metal objects using the wire wheel. I think that I will be OK with the machine only having a 1/3-HP motor. If not, then I will have experience for selecting a more powerful machine. Note: I am trying to minimize the number of machines that I have.

I assembled the machine, including replacing the stone wheel with the included wire wheel. The weaknesses are the grinder tool rest, and the belt-sander work table. The grinder tool rest is small and flexes (cantilever). It's a single stamped steel piece with one bend. The angle is not adjustable, but I don't need to adjust the angle for using a wire wheel. I might reinforce and enlarge the tool rest.

The work table does not appear to be meant to be set at an angle. The instructions say to use a square to set it it 90 degrees to the belt. Tightening the nuts and  bolts securely tends to change the angle. I plan to replace the work table, following Mikey's design in Modifying a Craftsman 2 X 42-inch Belt Sander for Tool Grinding.


----------



## mikey

Once you have a good platen and tool rest on that thing, you will be surprised how fast it can grind a tool bit. Don't forget that it needs ceramic belts to work well. I've found Red Label belts to work quite well on these machines. Here is an assortment pack to try your hand at it. You can then determine which grits work best for shaping and finishing your tools.


----------



## mwhite

mikey said:


> In a recent thread by @Darkbluesky, http://www.hobby-machinist.com/thre...tools-ideas-of-what-to-buy.62043/#post-511618, @ttabbal joked about sending me blanks to be ground into lathe tools ... he was joking! But it got me to thinking ... yeah, I know it's not a good thing when Mikey gets to thinking ... but it got me thinking that reading about how a tool is ground and having a decent tool in your hands that you can see and touch are two different things.
> 
> So, what if I ground a set of tools from 3/8" mild steel keystock (just to discourage some bozo from actually trying to cut something with the models) so people could hold it in their hands to look at. You could use them to plop onto your tool rest to see what the rest angles should be and maybe how your hands have to align to grind the tool. You could also buy some keystock and duplicate them for a permanent reference, and then pass them on to the next guy who wants to have a look.
> 
> I'm thinking of making *THREE* sets of these model tools and mailing them out to guys who are interested. We would need to figure out a list if there are more than three guys interested in seeing them, and YOU GUYS need to sort out how to keep track of these things. I would guess one to two weeks of holding time per person would be reasonable and the guy who has them would pay to flat rate ship it to the next guy on the list. Naturally, the only guys who can get on the list would be members of the HM forum.
> 
> As to which tools to include in the set, I'll leave that to you guys. We can discuss it here and see if we can come to some consensus. I will probably write a set of notes with details on how each tool is ground and why the angles are what they are and how you can modify them to better suit your needs; these notes would be posted to this thread.
> 
> I don't know if this is of interest to anyone but on the off chance that it is, let's talk about this and see if we can make it real. I'll spring for the keystock, grind the models and send them out. After that, you guys need to sort out how to get them distributed. The last guy on the list can hang onto them until some other HM member contacts them or you can send it back to me so I can do the same.
> 
> Let me be very clear about one more thing. The models will be of tools as *I* grind them for use in *my* shop on my lathe(s). It is one way, not necessarily the right way or the only way. My hope is that it will help you to find your own way of grinding tools that work for you.
> 
> Thoughts?
> 
> Mikey


Mikey, I would buy some key stock and ship it to you for the opportunity to have a set I can see. I would be happy to pass them along to the next person too.


----------



## mikey

mwhite said:


> Mikey, I would buy some key stock and ship it to you for the opportunity to have a set I can see. I would be happy to pass them along to the next person too.



No need for that. Jeff/@Z2V still has some models in circulation and can get them to you. I'm sure he'll be along soon, or you can PM him.

Welcome to HM!


----------



## Z2V

PM sent


----------



## tjb

Z2V said:


> PM sent


Wouldn't mind seeing that too, Jeff.  Can I be added to the circulation list?  Do you need me to send you a box?

Regards,
Terry


----------



## Z2V

Yeah, Terry. PM me your address and I’ll get a set to you.


----------



## mikey

Z2V said:


> PM sent



Thank you, Jeff.


----------



## Aukai

Terry, you might not get the box back, they'll probably be in a padded envelope, and he'll keep the box.


----------



## Z2V

Ahh...I have plenty of USPS small flat rate boxes. Our PO is fully stocked


----------



## tweinke

Amazing how this thread has kept going. A big Thank You to all who have kept this going. This has been an epic learning experience for me just reading along and seeing the success of others. I know this was the ah ha moment for me. I have had pretty good grinds and some not so good but the foundation teaching was spot on and I will try different variations and not feel baffled when it doesn't work right because i can look back here for reference. Hopefully my home improvement spree will be over soon and I can enjoy some shop time to relax and perfect my grinding skills. I have added a Rhodes shaper to my shop and am hoping to grind tools for it too. That may be a challenge in it self but I can get a lathe tool to make decent cuts so why not the shaper ones! Confidence was one of the things Mikey taught us too.


----------



## mikey

Yeah, over 99K views and still alive! You've been with us from the start, Todd, and I agree - we have all learned from, and about, each other in this one. In the very beginning, I said, " My hope is that it will help you to find your own way of grinding tools that work for you." You and so many others like you are doing exactly that and I couldn't have asked for a better result.

I join Todd in thanking all of you for making this thread so successful.

Almost forgot to add that @Ulma Doctor and I collaborated on some shaper tools. You might want to ask him about what works for him. He has a lot of experience with small shapers.


----------



## tjb

Aukai said:


> Terry, you might not get the box back, they'll probably be in a padded envelope, and he'll keep the box.


Oh, I fully anticipate that!  (Note that I in no way expressed or implied the box would be from part of the prized collection.)


----------



## tjb

Z2V said:


> Ahh...I have plenty of USPS small flat rate boxes. Our PO is fully stocked


It may be very suspicious if we hear of a news flash of a vandalism of the PO in Cedar Park, TX in which a large stash of flat rate boxes are missing.  Hmm.  (I must admit, however, those are really nice boxes!)

Regards


----------



## finsruskw

I fired up the belt sander yesterday and ground one of the 1/2 HSS blanks that came in a huge grab bag of tooling last month.
Thought I would try it out on a brass drift I've had in my tool box for years and it was getting rather beat up on the ends.
Left a decent finish I think although I was not impressed with the finish it left on mild CRS. Left a tiny grooved surface same as the insert tool I had used earlier.




	

		
			
		

		
	
I

I 
	

		
			
		

		
	



	

		
			
		

		
	
A bit off topic here .....
but I think I am having some stability issues with the SB relating to backlash on the compound and cross slide screws.
Perhaps I should look into replacing them??
I see there is a seller on e-bay that has the set for around $250 IIRC.


----------



## mikey

Hard to tell from the pics but your side relief angles look a bit shallow to me. Here is what I see:

Side relief looks to be maybe 5 degrees, possibly less. In the second picture the side walls look almost vertical. Could be the camera angle. If this is so, increasing the side relief angles will allow the tool to cut better.
There is very little relief under the nose so the tool is rubbing. I suspect this is why your finish is not as good as it should be.
The tool is not sharp. If you look carefully at the interface between the sides and top you can see light reflecting off that edge. That tells you that the intersection of those surfaces is not sharp and the tool will not cut nearly as well.
A round nose tool like this is capable of mirror finishes in brass, even with roughing cuts. The issue, at least from these pics, is primarily due to inadequate relief and perhaps suboptimal honing. All easily fixed. It may be that the backlash in your cross slide may play a role but I suspect that is not the issue.


----------



## finsruskw

Front relief was as produced on a new blank, 15*
set the table to 15*, marked the top 3/4" from the tip, scribed lines to the tip where they were 3/32" apart
and ground both sides to the top lines on the belt sander.

Will have to play with the tip some I guess.
The very bottom razor edge of the nose broke off before I got both sides ground.
Should the nose slope like that to a razor point on the bottom?


----------



## mikey

Okay, 15 degree side relief angles. I honestly do not see them in your pics but that is the nature of pics. The major problem is at the cutting point of contact at the nose anyway. This is a screen shot of the nose:




It may be the way the pic is displaying the angles but there appears to be very little, if any, relief under the cutting edge at the tip. This tool, as shown here, will rub with even small depths of cut.  Coupled with the generous nose radius, this lack of relief will deflect excessively. 

Again, the fix is simple - provide relief under the cutting edge at the tip. You can try hand-honing the relief under the tip but the way I would do this is to regrind the tool. I would simply grind the sides again but narrow the tip to a point. This will automatically create a relief angle underneath the tip. This relief angle will NOT be 15 degrees; it will be less but it will be adequate for this tool. Using your coarse diamond stone, hone a tiny flat across this tip at the nose; make it about 1/16" wide, no more. Make sure you follow the angle at the tip so the flat is even in width from the top of the tool to the bottom. 

Now, hone the sides with your coarse and then fine and then extra-fine diamond stones to remove the grinding marks. Do this without touching the nose or flat you created. Focus on getting the sides of the tool dead flat and free of grinding marks. Now use your fine stone to gently round the tip and blend the sides of the flat at the nose into the sides. Keep the nose radius small; you gain absolutely nothing by going so big. You simply want to round the nose while keeping that relief angle under the top edge intact. Once the major shaping of the nose is done, use your extra-fine stone to smooth everything out. If you run your finger over the cutting edge you should feel a burr from all this work.

Once all this work on the sides and nose radius is done, hone the top of the tool with your stones from coarse to extra-fine. Your goal is to make this top surface dead flat and even all the way across. The burr your raised when doing the sides will be removed when you hone the top but you may raise a small burr on the sides and at the tip when doing the top. If so, this is good because you know your honing is effective. Use your extra-fine stone on the sides and nose to get rid of the burr; it should only take a very light stroke upwards to get rid of the burr. 

At this point, the tool should be razor sharp. Look at the edges where the sides and end intersect with the top of the tool. There should be no light reflected off that edge or corner. Anywhere you see a reflection is a dull spot and you need to go back and fix that. Always hone to make the entire flat, flat.

Do not make the nose radius on a round nose tool too big. Big radii increase deflection and there is little value in this. I know the common wisdom is that big radii make for better finishes but if you think about it, the contact surface at the nose is very tiny with light cuts, maybe only a few thou across, so the size of the radius on light cuts doesn't matter much. What does matter is when you take heavy cut with a big nose radius; then you will see the deflection from that radius. Conversely, you will see far less deflection with a small nose radius.  So, a small nose radius is more accurate and will finish just as well as a large nose radius. 

If you like, test it yourself and see.


----------



## finsruskw

The last sentence in my previous post....

Should the nose slope like that to a razor point on the bottom? 
And look like the prow of a ship??

So, 15* relief angle on both sides and on the end, correct?
If the end angle of a new blank is already 15* and both side angles are ground to 15* how can it not wind up being be razor sharp at the bottom?

I will double check the table and make sure it is still set at 15*


----------



## mikey

finsruskw said:


> The last sentence in my previous post....
> 
> Should the nose slope like that to a razor point on the bottom?
> And look like the prow of a ship??
> 
> So, 15* relief angle on both sides and on the end, correct?
> If the end angle of a new blank is already 15* and both side angles are ground to 15* how can it not wind up being be razor sharp at the bottom?
> 
> I will double check the table and make sure it is still set at 15*



When you grind the sides and bring the grind up to the front of the tool bit, that sets the angle at the tip. Those side grinds will eliminate the ground tip of the bit and create a new one. This is why, despite using a 15 degree table angle, the angle under the nose may not be the same as the sides. Typically, the angle under the nose will NOT be 15 degrees; that's fine because it will be close - 12 degrees or so. It will suffice.

So yes, once the sides are fully ground the nose will look like the prow of a ship. Then you hone a flat on that nose and proceed as discussed.


----------



## finsruskw

Spent some more time on it and I think it will cut much better now.
Will have to get some aluminum to try it on.
Will find out in the morning!
Thanks for the critique!!

View attachment 336705


----------



## mikey

Better. Why not try it on that brass? I bet your finish will be a lot better.


----------



## finsruskw

I think Les is going to get some brass stock and try his hand at making few drifts and punches. He stole my Christmas gift idea right away as soon as I showed him the drift I cleaned up!!

I may just do that and clean up the whole length of it and redo the grooves as well.
Film at eleven!!


----------



## fcs

Probably shouldn’t post photo of your house key on the inter web.


----------



## Aukai

Dodge ignition key....


----------



## finsruskw

Aukai said:


> Dodge ignition key....


close!


----------



## tmenyc

Mikey,
Many thanks, as always, for the refresher course on honing.  After spending the whole covid summer holding my day job and a lot of employees together from my shop/turned office, free time is returning.  So I'm freshening up some of my tools and making a couple of new ones.  No matter how well I think I've metabolized your writing, seeing it in fresh words is always a new opportunity!

Tim


----------



## mikey

tmenyc said:


> Mikey,
> Many thanks, as always, for the refresher course on honing.  After spending the whole covid summer holding my day job and a lot of employees together from my shop/turned office, free time is returning.  So I'm freshening up some of my tools and making a couple of new ones.  No matter how well I think I've metabolized your writing, seeing it in fresh words is always a new opportunity!
> 
> Tim



You're welcome, Tim. Take care of yourself and remember to keep your flats, flat. As @mickri always reminds us, sharp tools cut better.


----------



## mikey

@finsruskw, anything to report on how your tool worked?


----------



## finsruskw

Haven't had a chance to use it yet.
Been pretty busy this week trucking and we are leaving on a trip to MO thursday.
I did buy an original 6" SB dog/face plate though that, at least hop should look like it belongs on the lathe!!


----------



## fcs

I’d love to get the model tools when they are free.

I admit I haven’t read _everything_ in the 44 pages here, but I started with Mikey’s instructions and ground my first bit yesterday, for aluminum with the big rake. Took me a long time, made one big mistake and uncounted small ones and the result is a pretty ugly tool which leaves a very nice finish but can’t take a deep cut. Something to work on tomorrow. I needed a new hobby to escape the news and this is it.


----------



## Z2V

fcs said:


> I’d love to get the model tools when they are free.



Send me a PM with your contact info and I’ll get a set of tool models headed your way.


----------



## mikey

fcs said:


> I’d love to get the model tools when they are free.
> 
> I admit I haven’t read _everything_ in the 44 pages here, but I started with Mikey’s instructions and ground my first bit yesterday, for aluminum with the big rake. Took me a long time, made one big mistake and uncounted small ones and the result is a pretty ugly tool which leaves a very nice finish but can’t take a deep cut. Something to work on tomorrow. I needed a new hobby to escape the news and this is it.



When you're ready, show us some pics. Maybe we can help.


----------



## Mr Mike

mikey said:


> In a recent thread by @Darkbluesky, http://www.hobby-machinist.com/thre...tools-ideas-of-what-to-buy.62043/#post-511618, @ttabbal joked about sending me blanks to be ground into lathe tools ... he was joking! But it got me to thinking ... yeah, I know it's not a good thing when Mikey gets to thinking ... but it got me thinking that reading about how a tool is ground and having a decent tool in your hands that you can see and touch are two different things.
> 
> So, what if I ground a set of tools from 3/8" mild steel keystock (just to discourage some bozo from actually trying to cut something with the models) so people could hold it in their hands to look at. You could use them to plop onto your tool rest to see what the rest angles should be and maybe how your hands have to align to grind the tool. You could also buy some keystock and duplicate them for a permanent reference, and then pass them on to the next guy who wants to have a look.
> 
> I'm thinking of making *THREE* sets of these model tools and mailing them out to guys who are interested. We would need to figure out a list if there are more than three guys interested in seeing them, and YOU GUYS need to sort out how to keep track of these things. I would guess one to two weeks of holding time per person would be reasonable and the guy who has them would pay to flat rate ship it to the next guy on the list. Naturally, the only guys who can get on the list would be members of the HM forum.
> 
> As to which tools to include in the set, I'll leave that to you guys. We can discuss it here and see if we can come to some consensus. I will probably write a set of notes with details on how each tool is ground and why the angles are what they are and how you can modify them to better suit your needs; these notes would be posted to this thread.
> 
> I don't know if this is of interest to anyone but on the off chance that it is, let's talk about this and see if we can make it real. I'll spring for the keystock, grind the models and send them out. After that, you guys need to sort out how to get them distributed. The last guy on the list can hang onto them until some other HM member contacts them or you can send it back to me so I can do the same.
> 
> Let me be very clear about one more thing. The models will be of tools as *I* grind them for use in *my* shop on my lathe(s). It is one way, not necessarily the right way or the only way. My hope is that it will help you to find your own way of grinding tools that work for you.
> 
> Thoughts?
> 
> Mikey



That has to be one of the coolest idea ever.... Your a good person Mikey..!
I didn't read all 44 pages I skimmed a bunch, I like helping people if I can but this is above and beyond... Very nice..!


----------



## mikey

Thanks, Mike, but this thread involves the input from a lot of folks and it isn't just me. Jump in and we'll try to give you any help we can.


----------



## Alcap

Lots of great info here on HSS , is there a thread like this for carbide tool bit sharpening ? I have plenty the came with my lathe and some in a tool box I bought , most with chipped tips , .


----------



## ttabbal

Alcap said:


> Lots of great info here on HSS , is there a thread like this for carbide tool bit sharpening ? I have plenty the came with my lathe and some in a tool box I bought , most with chipped tips , .




You mean the brazed carbide tools that are all over the place? The type you can't swap the insert on. Those you could do mostly the same stuff, but it would be much more difficult to shape them. You're mostly going to hone them. You could probably work the chips out with a diamond wheel, but it would be pretty slow going I would think. I've never tried it though. If I want carbide, I use inserts. 

If you try it, do some research. I seem to remember reading that carbide grinding dust is bad for your health. That could just be in my head though.


----------



## mikey

Alcap said:


> Lots of great info here on HSS , is there a thread like this for carbide tool bit sharpening ? I have plenty the came with my lathe and some in a tool box I bought , most with chipped tips , .



No, there is no equivalent thread like this for brazed carbide tooling on HM. Used to be a guy named Chris Poulsen (sp?) who could have done it but he left the site. If you have a green Silicone wheel and a diamond wheel then you can recondition and reshape brazed carbide tools. One of the Baldor-type tool grinding machines with cup wheels would do it easily. I have not worked much with brazed carbide tool grinding but I would imagine that the tool geometry would be similar.


----------



## fcs

I received the set of sample tools last weekend and I sat down and measured them and compared my numbers with the documented as a first step.

My question is not related to this, tho.  I there any hack for judging the size of the radius on a tool, some common item that is typically 1/64 or 1/32?  I don't have the urge to spend for a set of gauges when there is probably something lying on the workbench that will work. Eye of newt? Ball in a Bic pen?


----------



## brino

fcs said:


> My question is not related to this, tho. I there any hack for judging the size of the radius on a tool, some common item that is typically 1/64 or 1/32? I don't have the urge to spend for a set of gauges when there is probably something lying on the workbench that will work. Eye of newt? Ball in a Bic pen?



If you're just looking for a quick and available reference, how about the end of a drill bit shank?
Hold them side by side with good light and magnification if required.
-brino


----------



## mikey

There are a number of ways to do the nose radius - radius gauges, using drills or pins as examples, etc. I just grind a flat with my diamond stones about 1/64" across (I do this by eye; I don't use a ruler) and get that flat even from the top to the bottom of the tool. Then I just round and blend the edges of that flat into the side and end faces and call it good. 

It is not necessary to have the nose radius be an exact size but it is important for it not to be too big, at least in my opinion.


----------



## kb58

I talked to a retired machinist, mentioning how I was thinking of building a 2x72" belt sander for dressing HSS. He's used a belt sander himself for tool grinding, and somewhat surprised me by instead strongly recommended a used Baldor tool grinder. Just another data point on what people who know use.


----------



## mikey

A Baldor tool grinder is a nice tool to have. Slower than a belt sander with ceramic belts for shaping HSS but you can grind carbide on them, something that you cannot do on a belt sander. I don't think it matters a whole lot what you use to grind your tools; that is up to the user. However, I think it does matter that you understand WHAT you're grinding and WHY you're grinding it that way.


----------



## fcs

Mikey,
I was working  thru your first PDF and grinding the knife tool today, and in your writeup where you say " The end cutting edge angle is 65-70 degrees. " I think you mean (using the standard picture as reference) the angle is 30-35 degrees.  I should have looked at the grinding pictures more closely.  65 really does make a KNIFE tool.  I may be the first person dense enough to make that mistake; glad it was in keystock.


----------



## mikey

Yeah, you need to grind it like the model. Sorry for the confusion.


----------



## finsruskw

First cut on aluminum with the tool I ground a couple months ago.
and I am pleased with the results

Use the same tool to finish the chuck key for the bison I bought a while back as well.


----------



## mikey

finsruskw said:


> First cut on aluminum with the tool I ground a couple months ago.
> and I am pleased with the results
> 
> Use the same tool to finish the chuck key for the bison I bought a while back as well.



I meant to get back and respond to this post but life is truly hectic of late. My apologies.

For those of you who have not seen a tool like this before, it is called a Round Nose tool. It is characterized by the round nose radius, essentially identical side cutting edge profile on either side and typically has zero top rake. It is able to cut in either direction, which is helpful if you have to cut a section between two shoulders or collars. Due to the relatively large nose radius, a Round Nose tool tends to finish okay but it cannot take huge cuts without chattering. This is because the nose radius generates a lot of radial cutting forces. When compared to a general purpose turning tool, it is not capable of deeper cuts because of this.

In order for this tool to finish well you must do one of two things: slow the feed considerably or it will inscribe fine lines OR you can create a much smaller nose radius and alter your lead angle and use the edges just back/adjacent to the nose radius. This latter method will finish much, much better for you. Typically, I use a parting tool to make two adjacent cuts to create the shoulders on each side of the section being turned, then angle the tool so I am cutting with an edge instead of the nose. The finish is usually much better and because the edge cuts more accurately, it is easier to come in on size with this method. 

For those of you who have not tried this tool in brass, you are in for a treat. This tool will put a mirror finish on brass with almost no effort. Due to its versatility, this is a tool that is worth grinding. I suggest 15 degree side relief angles. Keep the nose radius small, about 1/32" will do. If you plan to use this tool strictly on brass, try grinding about 5-7 degrees of back rake on top; you will be very pleased at how well this tool cuts when modified this way. For use in other materials, use zero rake on top.


----------



## ACHiPo

Where is a good source for ground steel plate to back up the pyroceram glass?  The sources I found for ground steel are either too big, made of O1 or A2 (which seems overkill), etc.  This may be buried in the thread somewhere, but I don't remember seeing it and can't find it now.


----------



## hman

Don't know why you'd need ground steel.  I mount the pyroceram with JB Weld, as suggested by the source I bought it from.  JB Weld will cover a great multitude of sins.  Matter of fact, I lightly sandblast the substrate(s), just to give the JB some "tooth" to grab onto.  As I recall, I also sandblasted the back side of the pyroceram.


----------



## ttabbal

My pyroceram platen is JB Welded to el cheapo angle iron from a big box store. If you're really worried, machine or bolt a ledge on the bottom, but mine hasn't budged at all. I think if I replace it, I'll probably be best off replacing the whole steel part as well.


----------



## mikey

ACHiPo said:


> Where is a good source for ground steel plate to back up the pyroceram glass?  The sources I found for ground steel are either too big, made of O1 or A2 (which seems overkill), etc.  This may be buried in the thread somewhere, but I don't remember seeing it and can't find it now.



Personally, I used precision ground O-1 steel plate for my platen. I just prefer knowing the glass liner has a consistent layer of JB Weld between the liner and the substrate. I admit that I may be overly anal about this, though. I do have two 6-32 SHCS sitting under the lower edge of the liner, just in case.


----------



## ACHiPo

Not sure why I thought a ground plate was a good substrate?  I'll try just epoxying the pyroceram to my existing angle iron, which is on the flimsy side at maybe 1/8" thick, but the pyroceram and epoxy should stiffen it up quite a bit I'd think.  My sander is only a 1" wide belt.


----------



## ACHiPo

mikey said:


> Personally, I used precision ground O-1 steel plate for my platen. I just prefer knowing the glass liner has a consistent layer of JB Weld between the liner and the substrate.


So THAT'S where I got the idea!

Just ordered 2 pyroceram plates.  I'm a little concerned about excessive flex, but I figure it will be orders of magnitude better than my current angle iron backing.  Plus I have a spare just in case.


----------



## Jim F

Examples finally arrived.
@mikey, the turning tool you ground sure resembles the tool I have been using.
It came in a lot of bits.
Just looked right to me.
These examples are really nice.
I am going to take plenty of measurements.
The second pic is a tool I attempted to grind from Tom Lipton.
It has a 45 front and side, with a relief, 3 in 1 tool, face, turn,and chamfer.
My grinding skills need some work.


----------



## mikey

You will find that the shape of a tool has to do with access to features of the work;  getting into a corner or angle is sometimes necessary so we change the shape to suit our needs. Quick change tool posts allow us to quickly turn the tool and they have really influenced more modern tool shapes.

BUT what really matters are the relief and rake angles. They determine how effective and efficient the tool is. The more you understand what those angles do and how they can be chosen to suit the need, the better your lathe will work for you. The smaller and lighter the lathe, the more important these angles become. 

My advice to you is to take your time and try to understand why you are grinding what you're grinding. Spend most of your time, at least initially, grinding keystock. I suspect most guys don't follow this advice but of all the things I could tell you, this is the most important because you are learning to move your hands while your brain is sorting out what each angle does. It is then a simple step to sort out which angle to modify if you want your tool to be stronger at the tip or cut cooler or finish better or ...


----------



## mickri

Here is a question that I have been wondering about.  Searched the thread and didn't find an answer.  What is the purpose of the side angle?  I have used my square tool bit and my knife tool bit for general turning and can't see any difference in the cut, finish, etc.  I always take relatively light cuts.  Mostly .020 cuts to sometimes a .030 cut when roughing off material.


----------



## mikey

There are two key differences between the Square tool, or general purpose tool, and the Knife tool. First, the Knife tool has lower back rake angles; this focuses the cutting forces just to the rear of the nose radius, which is exactly where you want a facing tool to cut. Second, end cutting edge angle of the Knife tool is intended to allow better access to shoulders, while the tiny nose radius minimizes the root radius of that shoulder. The knife tool is a specialized tool meant for fine work.

The side angle you referred to is called the Side Cutting Edge Angle. This angle, along with the End Cutting Edge Angle on the end, define the shape of the tool and determine the ability of the tool to access parts of the work piece. It can be altered to suit your needs, as I know you realize. What differs between the Knife and general purpose tools are the tool angles and where they focus the cutting forces. This may seem like a piddly small difference but it matters, at least to me. I use the Knife tool as a facing tool, shoulder work and almost all the trepanning work I do. It also chamfers pretty good, too. The Square tool is used for almost everything else. When the tool angles allow adequate access I use it for shoulder work, too, but the nose radius tends to be larger than on a Knife tool so when that root size matters, the Knife tool comes out. 

Hope this helps.


----------



## moorejl57

I am new to this forum and I just went through this whole thread, quite a lot to take in, but very informative. I have a Sherline 4400 I bought back in 2004 and just now want to try grinding a general purpose square tool as you outline. I have been using the negative rake insert holder that is now obsolete. The finish is nowhere as good as a sharp hss tool. My question is about the side angle. In the instructions you mention marking the 3/8" blank at 1/8" at the top and 3/4" along the side to define the angle. Doing a little math, the tangent is sin/cos = 0.125/0.75 = 0.166667, and the angle is the arctan = ~9.5 degrees. Is this the angle I should set? I am going to grind a 1/4" blank since I have a handful of these and my tool holder is for 1/4" as well.


----------



## brino

@moorejl57,

Welcome to the group!

-brino


----------



## Janderso

Mikey,
Didn't you grind a bit for Ulma Doc's shaper back in 2018?
The beauty of HSS, you grind it right then just touch it up as needed.


----------



## mikey

moorejl57 said:


> I am new to this forum and I just went through this whole thread, quite a lot to take in, but very informative. I have a Sherline 4400 I bought back in 2004 and just now want to try grinding a general purpose square tool as you outline. I have been using the negative rake insert holder that is now obsolete. The finish is nowhere as good as a sharp hss tool. My question is about the side angle. In the instructions you mention marking the 3/8" blank at 1/8" at the top and 3/4" along the side to define the angle. Doing a little math, the tangent is sin/cos = 0.125/0.75 = 0.166667, and the angle is the arctan = ~9.5 degrees. Is this the angle I should set? I am going to grind a 1/4" blank since I have a handful of these and my tool holder is for 1/4" as well.



Welcome to HM!

Don't worry about precise angles for the side and end cutting edge angles. For a 1/4" square tool bit, mark about 2 times the thickness of the bit on the side, about 1/2". Then mark about 1/2 way across the top, roughly in the middle of the bit on top, then draw a line. Set the tool rest to whatever angle you wish (I suggest 15 degrees) to get your desired side relief angle and grind to the line. On the end, you want about an 80 degree included angle so draw that line and grind to it. Then do the rake angles as shown on page 4 of this thread and you're there.

I also have the 55 degree negative rake tool and while it works, a HSS tool will easily outperform it on your 4400. 

Let me know if you have questions.


----------



## mikey

Janderso said:


> Mikey,
> Didn't you grind a bit for Ulma Doc's shaper back in 2018?
> The beauty of HSS, you grind it right then just touch it up as needed.



I actually ground two of them; one for steel and one for aluminum. We actually had a long and fun discussion about what he wanted and he sent me the rectangular blanks. They seemed to work out well.


----------



## Janderso

mikey said:


> I actually ground two of them; one for steel and one for aluminum. We actually had a long and fun discussion about what he wanted and he sent me the rectangular blanks. They seemed to work out well.


I was down at his house picking up some equipment he donated to me after the fire. He showed me what he received from a fellow in Hawaii.
I put 2+2 together.
You know your stuff dood!


----------



## mikey

Thanks, Jeff. We took an unconventional approach to shaper tool geometry on those tools but it seemed to work well.


----------



## moorejl57

brino said:


> @moorejl57,
> 
> Welcome to the group!
> 
> -brino



Thanks!



mikey said:


> Welcome to HM!
> 
> Don't worry about precise angles for the side and end cutting edge angles. For a 1/4" square tool bit, mark about 2 times the thickness of the bit on the side, about 1/2". Then mark about 1/2 way across the top, roughly in the middle of the bit on top, then draw a line. Set the tool rest to whatever angle you wish (I suggest 15 degrees) to get your desired side relief angle and grind to the line. On the end, you want about an 80 degree included angle so draw that line and grind to it. Then do the rake angles as shown on page 4 of this thread and you're there.
> 
> I also have the 55 degree negative rake tool and while it works, a HSS tool will easily outperform it on your 4400.
> 
> Let me know if you have questions.



OK, got it, don't over think the side angle. Thanks for the quick response. All I have right now is a 6" grinder, but I think I can make it work for this.


----------



## mikey

Yup, a 6" grinder will work. I used one for over a decade to grind tools with so I know it will do the job. Just take your time and get the tool angles the way you want them and you'll be fine.


----------



## fcs

What tool will work well with bronze, either alloy c642 (duronze?) or c544? I am learning to make small fishing rod ferrules on my little Sherline. A good finish is more important than hogging off material. Any additional advise about working with this stuff  (drilling, reaming) is welcome.  Both these alloys are used successfully by others for the purpose, but they are using bigger machines. What is the machinability index? Its 60 for 642 and 80 for 544 I think.
—
Frank


----------



## mikey

I have never personally tried to turn either aluminum or phosphor bronze. However, my understanding is that the former is pretty hard and its machinability rating of 60 bears that out. I suspect that for these harder alloys, the typical zero rake tools we normally use for the brass/copper/bronze family will not cut well. If it were me, I would try a steel cutting tool like a square tool and see how that works.

All of these materials like very sharp edged tools so hone well.


----------



## fitterman1

I think any tool with a positive rake would be suitable for aluminium and bronzes for turning or milling.
Same for drilling into ally.
Drilling into brasses and bronzes you need to flatten the edge of the bit to a zero rake to prevent grabbing especially when about to break through. Not a hard and fast rule but it chips easier rather than create springs.


----------



## mikey

I just happened to see this video on Youtube today and it validates my early experiments with HSS tool grinding. Back then, about 30 years ago, Youtube didn't exist but my experiments were pretty close to what you can see in this video. I measured the power requirements of the lathe and compared them as I varied the relief and rake angles (side and back rake independent of each other) until I found what appeared to be the best compromise between rake and relief angles and edge wear. This eventually led to the design of my Square Tool.






About 5 years after my initial experiments, I learned about the Merchant Equation and the concept of the Shear Plane and how rake affects chip formation. I was then able to put together at least a basic understanding of what is happening at the cut and why altering the rake angles produces such benefit at the lathe. 

I truly wish I had seen this video way back when I started. It would have saved me a lot of independent experimentation and work. I must have ground close to 300 experimental tools to learn what you will learn in this video and I hope you find it interesting.


----------



## thomas s

Mikey, Thanks for posting that. What brand or make do you recommend for HSS tooling.


----------



## mikey

Happy New Year, Tom!

Most of my daily user tools like my square tools or material-specific general purpose tools, are simple M2 HSS. For the tools that have delicate tips, like my knife tool and threading tools, I use HSS-cobalt blanks because the small contact areas of these tips get really hot really fast. The higher red heat resistance of cobalt helps these tools retain their edges longer. 

As for brands, I much prefer Mo-Max and ETM (Iscar) M2 HSS, although most US-made HSS will be fine. I also like HSS blanks from Japan when I can find them. When I am experimenting with a grind to see how the angles work, I use cheap Chinese HSS blanks and they seem to work just fine, although I have convinced myself that the edges don't hold their sharpness as long as high quality blanks. I doubt that you would see a difference, though. 

For cobalt, I prefer Super-Mo-Max in M35 (5% cobalt) and M42 (8% cobalt). Most high cobalt Rex/Crucible blanks are good, as are the high Tungsten blanks from Rex/Crucible and Vasco. Most cobalt blanks from US makers are also very good. ETM makes some really good M35 cobalt bits but they're expensive. The Chinese cobalt stuff is okay but I do not rely on their claims of 5/8/10% cobalt because there is no documentation to confirm it. Still, I have used some Chinese cobalt and found it to be pretty okay.

If in doubt, go with US-made blanks. Mo-Max was made in the US until the late 1990's, I think. Then they moved production to Mexico but the blank quality from Mexico is still amongst the best you will find. Other US brands are Rex/Crucible, Morse, Do-All, Vasco/Teledyne and many others. 

Hope that helps.


----------



## 7milesup

How does one go about getting on the list for these grinding models you speak of?


----------



## Jim F

7milesup said:


> How does one go about getting on the list for these grinding models you speak of?



@Z2V  handles the list.


----------



## Aukai

Darn, I thought I was going to read about Big Block Chevys 
Very informative though


----------



## Jim F

Aukai said:


> Darn, I thought I was going to read about Big Block Chevys
> Very informative though


Sorry, but I bleed Blue.........


----------



## Aukai

That's why there are tow trucks


----------



## Jim F

And they are Ovals or Billygoats......


----------



## Jim F

Back on topic, @mikey , will that cheapo HF diamond block work for honing ?


----------



## mikey

Jim F said:


> Back on topic, @mikey , will that cheapo HF diamond block work for honing ?



Sorry, I haven't used them before so I cannot say. I can tell you that DMT credit card stones work well, though.


----------



## thomas s

Happy New Year to you too Mikey. And thank you for the information on HSS tools.


----------



## Karl A

Here is a term that I don't understand the meaning: "face out". Here are examples of the term being used:

"*Right Hand Knife Tool:* This is a kick ass facing tool. Like all facing tools, this one cuts at the side cutting edge up close to the tip. Because all the cutting is at the side edge, the nose radius does not participate much at all and can be small; this allows you to go into the corner of a shoulder and face out without leaving a huge radius at the root/corner. The side relief angle is 15° so it takes light or heavy facing cuts easily. The back rake is more conservative and this focuses the cutting forces toward the side cutting edge, which is what we want with a facing tool." - mikey; this thread; Sept 20, 2017 (#102).

"The knife tool is really stiff but also has a rather delicate tip that allows it to get into a tight corner and face out. The tip also allows you to chamfer inside or outside corners and grooves. But what the knife tool excels at is facing. It has a long, sharp edge that allows you to skim cut a face and leave a beautiful finish, better than any other tool I’ve seen. All you need to do is get the cutting edge just off parallel with the work, come into contact and face out." - mikey; this thread; Sept 23, 2017 (#135).

"Since this tool is a general purpose tool, meaning it can turn, face or finish, it must be able to cut into a shoulder and then be able to face out. To accomplish this we will make the end cutting edge angle less than 90° so it can access corners without rubbing." mikey; the thread "How to Grind a Hss Turning Tool";  Nov 29, 2016 (#1).

I found this diagram:


https://www.summaryplanet.com/engineering/Machining-shoulders-corners-undercuts-grooves.html

Does this diagram show what is described in the first example, "...this allows you to go into the corner of a shoulder and face out without leaving a huge radius at the root/corner", and in the third example, "...it must be able to cut into a shoulder and then be able to face out"?

Karl


----------



## Aaron_W

Karl A said:


> Here is a term that I don't understand the meaning: "face out". Here are examples of the term being used:
> 
> "*Right Hand Knife Tool:* This is a kick ass facing tool. Like all facing tools, this one cuts at the side cutting edge up close to the tip. Because all the cutting is at the side edge, the nose radius does not participate much at all and can be small; this allows you to go into the corner of a shoulder and face out without leaving a huge radius at the root/corner. The side relief angle is 15° so it takes light or heavy facing cuts easily. The back rake is more conservative and this focuses the cutting forces toward the side cutting edge, which is what we want with a facing tool." - mikey; this thread; Sept 20, 2017 (#102).
> 
> "The knife tool is really stiff but also has a rather delicate tip that allows it to get into a tight corner and face out. The tip also allows you to chamfer inside or outside corners and grooves. But what the knife tool excels at is facing. It has a long, sharp edge that allows you to skim cut a face and leave a beautiful finish, better than any other tool I’ve seen. All you need to do is get the cutting edge just off parallel with the work, come into contact and face out." - mikey; this thread; Sept 23, 2017 (#135).
> 
> "Since this tool is a general purpose tool, meaning it can turn, face or finish, it must be able to cut into a shoulder and then be able to face out. To accomplish this we will make the end cutting edge angle less than 90° so it can access corners without rubbing." mikey; the thread "How to Grind a Hss Turning Tool";  Nov 29, 2016 (#1).
> 
> I found this diagram:
> View attachment 350630
> 
> https://www.summaryplanet.com/engineering/Machining-shoulders-corners-undercuts-grooves.html
> 
> Does this diagram show what is described in the first example, "...this allows you to go into the corner of a shoulder and face out without leaving a huge radius at the root/corner", and in the third example, "...it must be able to cut into a shoulder and then be able to face out"?
> 
> Karl



Yes, that is what your example shows. You will often see a small groove or relief cut at the base of a corner where you need to have two parts come together tightly. With out that groove you will often have a slight gap where the corner forms, or a small bevel on the matching face. 

A narrow tool like this allows you to either make a very small groove, or if a very small gap is acceptable maybe just skip that step. Since it is useful for other operations you may not need to change tools just to finish that corner.


----------



## fitterman1

Karl A said:


> Here is a term that I don't understand the meaning: "face out". Here are examples of the term being used:
> 
> "*Right Hand Knife Tool:* This is a kick ass facing tool. Like all facing tools, this one cuts at the side cutting edge up close to the tip. Because all the cutting is at the side edge, the nose radius does not participate much at all and can be small; this allows you to go into the corner of a shoulder and face out without leaving a huge radius at the root/corner. The side relief angle is 15° so it takes light or heavy facing cuts easily. The back rake is more conservative and this focuses the cutting forces toward the side cutting edge, which is what we want with a facing tool." - mikey; this thread; Sept 20, 2017 (#102).
> 
> "The knife tool is really stiff but also has a rather delicate tip that allows it to get into a tight corner and face out. The tip also allows you to chamfer inside or outside corners and grooves. But what the knife tool excels at is facing. It has a long, sharp edge that allows you to skim cut a face and leave a beautiful finish, better than any other tool I’ve seen. All you need to do is get the cutting edge just off parallel with the work, come into contact and face out." - mikey; this thread; Sept 23, 2017 (#135).
> 
> "Since this tool is a general purpose tool, meaning it can turn, face or finish, it must be able to cut into a shoulder and then be able to face out. To accomplish this we will make the end cutting edge angle less than 90° so it can access corners without rubbing." mikey; the thread "How to Grind a Hss Turning Tool";  Nov 29, 2016 (#1).
> 
> I found this diagram:
> View attachment 350630
> 
> https://www.summaryplanet.com/engineering/Machining-shoulders-corners-undercuts-grooves.html
> 
> Does this diagram show what is described in the first example, "...this allows you to go into the corner of a shoulder and face out without leaving a huge radius at the root/corner", and in the third example, "...it must be able to cut into a shoulder and then be able to face out"?
> 
> Karl


Looking at your drawing, by following the arrow no 2 in that direction is known as facing out.
When you're facing in, its towards center.
With regards to a radius in the corner, it may be desirable to have one ultimately giving that joint less chance of creating stress cracks.
And if you wish a mating part to sit flush, then chamfer the mating part taking into consideration the size of the radius.
A knife tool is just that, a sharp point.


----------



## mikey

Yup, I agree with Aaron and fitterman. Facing in or out depends on the direction of feed.


----------



## fitterman1

Also, please take note that when using the knife point facing out is a prerequisite to a good finish whereas facing in with this tool will create a terrible finish.
Totally dependent on the point radius.


----------



## DavidR8

I've been a member since Oct 2019, just over a year now and I have to make a confession.
Until tonight I have not ground a HSS tool completely following the excellent instructions in this thread. 
I told myself that tonight was the night I would do it. I read the instructions, had the model for the knife tool handy and fired up the belt sander.
Quite literally, five minutes later I had a reasonable facsimile of the knife tool, sharp enough that I slipped and cut my finger while honing.
(ignore the other bevel on the middle picture that's leftover from a trepanning tool experiment)






Put it in a holder, lined it up to centre and proceeded to turn some 1018 and 12L14.
Got a decent finish on the 1018, could take as light a cut as .0025 and as much as .050 with ease. The chips were tight little curls. 


I am truly amazed and a total convert!
Thank you @mikey!


----------



## mikey

Good job, Dave! Now go make a Square Tool - that will outperform a knife tool for general use any day.


----------



## DavidR8

I misspoke, I tried to copy the square tool but angles were a bit off.


----------



## Jim F

DavidR8 said:


> I misspoke, I tried to copy the square tool but angles were a bit off.
> View attachment 350771


Better than my attempt.......


----------



## DavidR8

Jim F said:


> Better than my attempt.......


There's definitely a knack to it!
Keep at it though, the payoff is unbelievable!


----------



## Jim F

DavidR8 said:


> There's definitely a knack to it!


I don't have a belt sander, so bench grinder is a little trickier.


----------



## DavidR8

Jim F said:


> I don't have a belt sander, so bench grinder is a little trickier.


It would be a bit trickier. I think the rest makes a big difference. I also have a bench grinder so I want to try on that as well. The top rake was tricky to grind on my belt sander because the platen is about 1/8" wider than the belt so the belt wants to push away from the tool. I have some mods in mind to fix that problem.


----------



## Aukai

I put diamond wheels on my bench grinder just for that reason Dave. Every thing is done on my belt, even the top rake I just finish it on the wheel.


----------



## Jim F

I thought I read that Diamond does not like tool steel ?


----------



## DavidR8

Aukai said:


> I put diamond wheels on my bench grinder just for that reason Dave. Every thing is done on my belt, even the top rake I just finish it on the wheel.


Do the wheels look like CBN wheels?


----------



## Aukai

Not sure, I was not advised against it. Yes I was meaning CBN wheels.


----------



## DavidR8

What grit @Aukai?


----------



## mickri

When I first started with this I didn't have either a bench grinder or a belt sander.  The only thing I had was a Makita high speed grinder.  My first attempts were beyond ugly and didn't work very well.  Lucky for me that my lathe came with a bunch of already ground tool bits. Then came the bench grinder and things got a little better.  Still very difficult to get the angles right.  Stumbled onto a 1x42 belt sander in a consignment store.  What a difference that made.  I could set the table to whatever angle I wanted and combined with my combination square I could grind anything I wanted to.  I tried honing for awhile.  Not very good at honing.  I was rounding off the edges.  I have a 320 grit belt that polishes the scratches to a mirror finish in no time and keeps the edges sharp.  No more honing.

My current sharping dilemma is trying to grind the 1/8" round tool bits for my smallest boring bars.  Working on ways to hold the tool bit.  I'll get it figured out.


----------



## Jim F

Been keeping an eye out for a belt sander, but the ones I see are overpriced or too big.


----------



## DavidR8

I have this one @Jim F








						Dayton 6Y945 Belt & Disc Sander 1/3 HP 120V for sale online | eBay
					

Find many great new & used options and get the best deals for Dayton 6Y945 Belt & Disc Sander 1/3 HP 120V at the best online prices at eBay! Free shipping for many products!



					www.ebay.com


----------



## mickri

Mine is an old Delta.  Paid $40.

Jim this one is just like mine  $75 and appears to be in better condition than mine.  Comes with a stand. Craftsman 1 x 42 Belt Sander with Metal Wheels - tools - by owner -... (craigslist.org)


----------



## Jim F

mickri said:


> Mine is an old Delta.  Paid $40.
> 
> Jim this one is just like mine  $75 and appears to be in better condition than mine.  Comes with a stand. Craftsman 1 x 42 Belt Sander with Metal Wheels - tools - by owner -... (craigslist.org)


Just sent an email.


----------



## Aaron_W

Jim F said:


> I don't have a belt sander, so bench grinder is a little trickier.



I have a bench grinder too. 

Somewhere in all these posts there was a suggestion of marking the angles directly onto the tool bit with a Sharpie. I've found that helped a great deal.


----------



## Aukai

Off the top of my head Dave I have 220, and 80. 36 grit ceramic on the belt


----------



## DavidR8

Aaron_W said:


> I have a bench grinder too.
> 
> Somewhere in all these posts there was a suggestion of marking the angles directly onto the tool bit with a Sharpie. I've found that helped a great deal.


Yup, if I'd been smart I would have blued it up and drawn some lines...


----------



## Aukai

Protractor, and a thin sharpie too...


----------



## mikey

Lines? We don't need to stinking lines!  

Just joking. I think lines are a good idea when you first start grinding tools but you'll eventually get to where you don't need them. Personally, I start grinding the side cutting edge first and try to make the length of that side edge end up about 2 times the width of the bit while ALSO grinding about halfway across the width of the bit for a general purpose tool. Neither goal is all that critical but I've done so many that I can probably hit these dimensions within a few thou. Just start grinding it and don't stress over it too much.

Next, grind the end. Just grind it to produce about an 80 degree angle. You can eyeball 90 degrees with amazing accuracy so just make it a bit less than that and it will be fine. You are simply making sure you can access a shoulder, that's all.

To do the top rake angles, eyeball 1-1/2 times the width and put that estimated point at the edge of the wheel or belt, estimate your back rake angle and just grind until the pattern just reaches the tip, then stop.

Look, I know I gave you specific angles to hit. That's because the tool works well at those angles. My tools will be within a degree or less when I'm done but if you are off a degree or two, I guarantee you that the tool will still work fine. And if it doesn't or you think it might work better with a bit more relief or back rake or side rake then just go back and grind it in.

It is important to realize that all lathes are different. They have different degrees of rigidity, power, speed, wear and a different operator. Accordingly, our tools must differ if we are to maximize the performance of our specific lathe. If you think you need to be able to cut deeper, try more side rake. If your finish could be better, try more back rake (bet you thought I was going to say increase the relief angles or make the nose radius bigger, eh?). Mess with the grind and see what works for you; that is what this whole thread was about.

There are no rules when grinding lathe tools - you just gotta try it and see what happens, then figure out what you did and what worked and what didn't.

As for honing, that is a personal choice. I hone because I feel that a refined edge cuts better and lasts longer but there is certainly no rule that require you to hone your tools. I will say this, though; try honing your tools with your diamond stones, then hit it on a fine India stone and then on a Translucent or Hard Arkansas stone and see what it does to your finishes. It will make you a believer. That tool will also take a tenth off the diameter if you can dial it in.


----------



## Downunder Bob

I find all this talk of grinding lathe tools by hand very interesting .From the time I was an apprentice to about a year ago I never had access to a belt grinder/sander. I acquired a very small belt sander 1" wide belt. I was taught to grind tools on a pedestal grinder usually 6" x 1" wide Al Ox wheel, usually 60 grit, Occasionally 8" wheel but again 60 grit. I have, since getting my lathe, about 4 years ago, used a box of old tools left over from my apprenticeship and other more recent adventures, and have only rarely needed to regrind a tool, and when needed I have used a 5"angle grinder to rough it out, and then, and only recently, used the small belt sander to finish, this was also a 60 grit belt.

What I find most interesting is all the talk about stoning and hand finish with special stones etc. I was not taught to do this, and as a result I have never done it. remember I was trained in a toolroom, and neither I, nor the tradesmen who were teaching me, ever had a problem with finish. I can only think the difference is HP, large powerful machines can run tools with good sized radius on the nose.. 

Having said that my lathe is only 1.5HP and single Ph at that, Also I have never noticed single phase chatter, We run 240V 50Hz single Ph here in Australia. Maybe that is the difference. Can any one else also running 240V 50Hz single ph. comment please.


----------



## Jim F

mickri said:


> Mine is an old Delta.  Paid $40.
> 
> Jim this one is just like mine  $75 and appears to be in better condition than mine.  Comes with a stand. Craftsman 1 x 42 Belt Sander with Metal Wheels - tools - by owner -... (craigslist.org)


Still available, hoping to go tomorrow to get it.
3 hr drive 1 way.


----------



## ttabbal

Prebuilt belt grinders are pricey. I'm not sure why, they aren't that complex. I built mine from free plans online. Simple cutting and welding. No real critical dimensions, a tape measure is plenty accurate. A bandsaw is helpful, but people have done it with a hacksaw. An abrasive chop saw would work as well. 

I do most grinding with 36 grit ceramic belts. Then switch to diamond cards. I did find that using wet sandpaper on glass at about 100 grit helps get the grinding lines out. Just pushing less hard at the end helps a lot as well. I have belts as well, but keeping from grinding facets that way is more difficult and it usually only takes a minute to get to where the cards are the best option. 

I also put the cards on a flat surface and run the bit over them. It takes practice to hold the bit at a compound angle consistently, but you get used to it. Use a larger surface than the card, so you can use it as a reference while moving. I usually rest part of my hand on the surface to help keep things aligned.


----------



## Jim F

ttabbal said:


> Prebuilt belt grinders are pricey. I'm not sure why, they aren't that complex. I built mine from free plans online. Simple cutting and welding. No real critical dimensions, a tape measure is plenty accurate. A bandsaw is helpful, but people have done it with a hacksaw. An abrasive chop saw would work as well.
> 
> I do most grinding with 36 grit ceramic belts. Then switch to diamond cards. I did find that using wet sandpaper on glass at about 100 grit helps get the grinding lines out. Just pushing less hard at the end helps a lot as well. I have belts as well, but keeping from grinding facets that way is more difficult and it usually only takes a minute to get to where the cards are the best option.
> 
> I also put the cards on a flat surface and run the bit over them. It takes practice to hold the bit at a compound angle consistently, but you get used to it. Use a larger surface than the card, so you can use it as a reference while moving. I usually rest part of my hand on the surface to help keep things aligned.


No welder.


----------



## tweinke

I built my 2x72 with no welding. Why just to see if i could.


----------



## mikey

Downunder Bob said:


> What I find most interesting is all the talk about stoning and hand finish with special stones etc. I was not taught to do this, and as a result I have never done it. remember I was trained in a toolroom, and neither I, nor the tradesmen who were teaching me, ever had a problem with finish. I can only think the difference is HP, large powerful machines can run tools with good sized radius on the nose..


The way I see it, Bob, any defect existing on the tool's edges will transfer to the work piece and I know, at least to my eye, that honing produces a better finish. Just as important is that a honed edge lives longer and cuts more accurately. If we are turning a rough work piece for a tractor then this may not matter but if we are turning an arbor that has tolerances in the low tenths then I feel it does make a difference. 

I did an experiment with gravers once. I tried turning a brass ball with a graver right off the grinder and that graver was really difficult to use; it dug in and would not produce a decent finish. A few minutes of honing allowed the tool to turn with ease and produced a mirror finish. This just reinforced what I learned with lathe tools - honing does make a difference.


----------



## Jim F

mickri said:


> Mine is an old Delta.  Paid $40.
> 
> Jim this one is just like mine  $75 and appears to be in better condition than mine.  Comes with a stand. Craftsman 1 x 42 Belt Sander with Metal Wheels - tools - by owner -... (craigslist.org)


@mickri
I am getting this in the am.
If your ever in my neck of the woods I owe you a drink or 2.


----------



## Jim F

Now I need to order belts........
Suggestions ?



			Amazon.com


----------



## Aukai

Red Label Ceramic 36 grit here.


----------



## mikey

I suggest this set to see which belts work best for you.


----------



## mickri

Your local Ace Hardware may have some to get you started.  I have ordered belts from Abrasive Belts | Tru Grit, Inc. | The Leading Edge in Abrasives and Knifemaking Supplies


----------



## Jim F

Where do you get glass platens ?


----------



## mickri

If you get a belt sander like mine you won't need the glass platen.  There is a support arm that can be swung down to support the top of the platen on theses belt sanders.  In the picture I am setting the angle of the table to 15 degrees with a combination square.


----------



## Jim F

mickri said:


> If you get a belt sander like mine you won't need the glass platen.  There is a support arm that can be swung down to support the top of the platen on theses belt sanders.  In the picture I am setting the angle of the table to 15 degrees with a combination square.
> 
> View attachment 350996


Mine is similar, has metal wheels, and a sheet metal table.
My wheel does not reach the platen, it touches the belt above the platen.


----------



## mikey

I would like to offer a different perspective on glass platen liners. These liners are more to provide a long lasting flat surface that lasts for years in a hobby shop. Steel platens wear and dish out over time and you cannot grind a flat surface on a dished platen. 

1" platen liners are harder to find but this guy has them and also has a video on how to install them. I would suggest that you make the platen support as rigid as you can because it is supported only on one end. @darkzero and @Aukai made some nice ones for their Jet sanders.


----------



## Jim F

Well, it fits in the basement, so I can atleast practice grinding even if I can't use the lathe.


----------



## hman

"Glass" platen liners (aka pyroceram) for belt sanders/grinders are available from lots of sellers who support knife making.  Try Google-fu with the search term "pyroceram belt grinder" and you'll get lots of hits.


----------



## Jim F

mikey said:


> I suggest this set to see which belts work best for you.


I hope they last for that price.


----------



## Aukai

Mine is going on 2 years.


----------



## mickri

Here are links to manuals at Vintage Machinery.  4129.pdf (vintagemachinery.org) and Full page fax print (vintagemachinery.org)  They appear to be identical but have different part numbers.  The support for the wheel that sits just above the platen has a slot in it.  I wonder if you can lower it to reach the platen or make a longer one.  Have fun with your belt sander.  I use mine a lot for all kinds  sanding.  Not just to grind tool bits.


----------



## mikey

Aukai said:


> Mine is going on 2 years.



Yup, I agree. They seem to cut faster, cooler and last way longer than other belts.


----------



## ACHiPo

mickri said:


> If you get a belt sander like mine you won't need the glass platen.  There is a support arm that can be swung down to support the top of the platen on theses belt sanders.  In the picture I am setting the angle of the table to 15 degrees with a combination square.
> 
> View attachment 350996


I have a sander like that.  I added a glass platen today (finally) and trust me it works really nicely!  Well worth the effort and minor expense.


----------



## Karl A

fitterman1 said:


> Also, please take note that when using the knife point facing out is a prerequisite to a good finish whereas facing in with this tool will create a terrible finish.
> Totally dependent on the point radius.


I faced in, and then faced out, on a short 1-inch diameter 6061 aluminum rod, using a knife  tool.  Depth of cut was 0.02 inch. Spindle was turning at 800 rpm. I don't know what the feed rate was. The chips were very different. See below. The chip from facing in is above; the chip from facing out is below.


I think I can see why facing out produces a better finish. It's like having a large nose radius.

When I read about facing out with a knife tool, I doubted that facing out means what I means. It seemed wrong -- that to face out is to orient the x-y surface with a negative clearance angle.


----------



## fitterman1

What was the finish like between the two?


----------



## Karl A

fitterman1 said:


> What was the finish like between the two?


I don't see a difference using a 10X loupe. There was chatter during facing out, though.


----------



## fitterman1

I would have expected a rougher finish facing in, but I expect that will be dependent on feed speed.
Your chatter facing out is a sum of the combination of depth of cut and feedspeed.


----------



## Brento

I an not sure if a table like this exists but i am sure it will help.


			http://www.steves-workshop.co.uk/tips/toolgrinding/tool-grinding-poster.pdf


----------



## Brento

Im buying a little Derbyshire so i will be referring to that chart more


----------



## fitterman1

Would it be ok to save that in the downloads section for future reference?
Mods?


----------



## Brento

Where is the downloads section for the thread?


----------



## fitterman1

There isn't one specifically for this thread i think. You add it to your own little download stashbox.
Hit the 3 bars higher up the page on the left and scroll down for downloads.
You should be able to upload a file under your name somewhere. And it becomes available to others.


----------



## mikey

@Brento, the downloads section is accessible only by becoming a contributing member.


----------



## mikey

Karl A said:


> I faced in, and then faced out, on a short 1-inch diameter 6061 aluminum rod, using a knife  tool.  Depth of cut was 0.02 inch. Spindle was turning at 800 rpm. I don't know what the feed rate was. The chips were very different. See below. The chip from facing in is above; the chip from facing out is below.
> View attachment 351119
> 
> I think I can see why facing out produces a better finish. It's like having a large nose radius.
> 
> When I read about facing out with a knife tool, I doubted that facing out means what I means. It seemed wrong -- that to face out is to orient the x-y surface with a negative clearance angle.



Karl, the reason the chips differ is because the area of contact differs between the two directions. If the tool is oriented properly the side cutting edge just to the rear of the nose radius is doing the cutting when facing out; the nose radius is not involved at all. However, when facing in, the nose radius is definitely involved; depending on how it is ground it can have a significant impact on finishes, chip form and efficacy. Remember, too, that if the cut is deep enough to bury the nose radius in the cut then there is very little cutting edge to the right side of the nose radius due to the shape of the tool so the nose radius is taking the full load. Accordingly, the chip form will definitely differ.

A knife tool is not intended to hog metal. It is an awesome facing tool and is capable of taking microscopic turning cuts but it is not intended for heavy cuts. To me, a 0.020" deep cut is a heavy cut for a knife tool; for heavier cuts a square tool would work better because the geometry is designed to handle it. A knife tool is best used to produced finely finished and accurate facing cuts. With light cuts, it will typically produce a fine finish regardless of feed direction.


----------



## Karl A

Mike,

I read the first half of your post several times while having a knife tool in hand as a visual aid. I think that I understand it.

One challenging aspect of understanding what is going on is that the tool moves in two directions relative to the material being cut, due to speed (rotating piece) and feed.

By the way, the old BBC film on cutting tools that you recommended is helpful to me.

I will remember that a knife tool is for light cuts.

Karl


----------



## mikey

The thing to remember is that in order for a tool to cut, there must be an edge to do the cutting. A knife tool has a side cutting edge but because of the acute end cutting edge angle at the tip of the tool, there is no END edge to cut with. Therefore, the nose radius does it all when feeding in with the nose radius buried in a deep cut, resulting in an ugly gnarly chip. The side cutting edge is behind the nose radius and because it is producing a shearing cut on the face the finish is generally fairly good, even with deep cuts. 

Now, contrast this to a square tool that DOES have an end cutting edge. Face IN with that tool and the nose radius and end cutting edge are now doing the cutting and the chip will peel off nicely. Of course, cutting forces increase because you have a lot more edge contact so you need to slow down your speed a little or you risk chatter. If you do so, a 0.020" deep cut is nothing for a square tool on a Sherline lathe.

Be aware of your edges, learn how they work and how to use them to your advantage. I suspect most hobby guys can learn a lot by studying how a tool cuts.


----------



## Brento

A knife tool is basicaly a finishing tool correct?


----------



## mikey

No, it isn't. Because of the small nose radius it doesn't finish well when turning unless you feed really slow. It excels as a facing tool and finishes well there because the side cutting edge is what does the cutting. 

A finishing tool in years past had an exaggerated side cutting edge angle. This was because the shank of the tool was held perpendicular to the work piece and the side angle was ground to produce the desired lead angle. However, today, we have QCTP's so we can use a general purpose tool and just change the lead angle to reproduce that of a finishing tool. This one tool can rough, size, finish and face simply by changing the lead angle of the tool so that the desired part of the edge hits the work.


----------



## Brento

Is the knife to best tool then to grind then for the most part?


----------



## Jim F

Brento said:


> Is the knife to best tool then to grind then for the most part?


The square tool is the most versatile.


----------



## Karl A

mikey said:


> ... Be aware of your edges, learn how they work and how to use them to your advantage. I suspect most hobby guys can learn a lot by studying how a tool cuts.


To learn how tools cut and then to use that understanding to my advantage was one of my motives for getting into machining. Cutting is a core technology.

In 2017, I visited a cousin in Tokyo. She took me to a dessert shop and bought me a piece of cake that had many layers. I admired how well the piece had been cut: no displacement of the layers relative to each others and no apparent smearing of the layers. She explained that it had been cut with a very sharp knife.


----------



## Jim F

ACHiPo said:


> I have a sander like that.  I added a glass platen today (finally) and trust me it works really nicely!  Well worth the effort and minor expense.
> 
> View attachment 351118


Did you have to do anything to the glass before gluing it on ?


----------



## hman

I've slightly rounded the leading and trailing edges, just so it can't damage the sanding belt.  Maybe just a bit on the sides to keep from hurting my fingers if I slip.


----------



## Jim F

hman said:


> I've slightly rounded the leading and trailing edges, just so it can't damage the sanding belt.  Maybe just a bit on the sides to keep from hurting my fingers if I slip.


Any thing to get the glue to stick ?


----------



## hman

I can't recall if I did this or not ... but I do have a very fine grit sandblaster (bought from somebody who made dental castings) and might possibly have added some "tooth" to the rear surface.  A thorough cleaning should be enough, however.


----------



## mikey

I also grind the top, bottom and side edges to smooth it out. I then used some 120 grit sandpaper to lightly scuff the glass and the plate it mounts to, then blew it clean and wiped several times with acetone. I used JB Weld and used multiple spring clamps to hold it down until it dried. Next time, I'll use masking tape instead.


----------



## Jim F

Just checking. I know I used to scuff windshields when re-installing mirror buttons.
My platen shipped today.


----------



## Brento

If i showed a picture of a tool that was ground from a previous owner that came with my watch makers lathe could someone identify maybe what it could have been ground to cut? ie brass, aluminum, steel?


----------



## Aukai

I do believe we have experts in house, and the picture would help immensely in the evaluation...


----------



## mickri

Post several good pictures from different angles.  You will get responses.


----------



## Brento

Will do!


----------



## mickri

No expert but they look like right hand cutting tools.  The 2nd picture looks to have a fair amount of nose radius.  I would think it would be for general turning.  The last picture looks to have a sharp nose.  No radius.  Probably used to turn to a shoulder.  Maybe facing too.  The biggest feature consistent to all of the tool bits is the back rake.  Instead of angling down from the tip it angles up.

Mikey will chime in here with his expertise.


----------



## fitterman1

Too much negative rake, you'll melt your work, or discover how friction welding occurs.
You need to look into the effects a positive rake has on the tool first.


----------



## Brento

All those pictures are just one tool. Not sure what material it was ground for


----------



## Aukai

Does it have to be a lathe tool, maybe a pin driver or a punch, form tool?


----------



## Profkanz

Negative rake is common for brass which tend to be grabby with positive rake cutters. Its why we have to dub the cutting lips on twist drills when drilling brass.


----------



## Brento

It is in a tool post on my watch makers lathe


----------



## Brento

When talking about the negative rake are you talking about the back?


----------



## Aaron_W

Brento said:


> It is in a tool post on my watch makers lathe



That would make sense for some of the comments about brass, a common clock / watch material. I have some books on watchmaking, I'll see if there are any pictures of a similar tool. 

Of course it could be a tool made by a deranged person.


----------



## Brento

He was a very good machinist that i bought the lathe from. He didnt do anything with watches if i remember correctly. He i believe made that tool post so i dont think its from another previous owner.


----------



## fitterman1

Brento said:


> When talking about the negative rake are you talking about the back?


Imagine a capital T on its side so the top of it is now vertical and the leg is now pointing to the right in mid air.
The vertical is your work rotating clockwise as you view it.
The horizontal line is the top of your tool.
If you tilt that leg down to say half past 3 your tool is said to have positive rake.
At 3 o clock it it neutral.
At half past 2 it is negative.
Looking at the same tool head on, that same edge will slope away to the left to give you another rake, also positive. This is called its side rake. There are other rakes and reliefs to take into account when grinding tools up. Its now upto you to discover them.


----------



## fitterman1

Actually, looking at your pictures again, the first and fourth have it mounted in the correct orientation.
The others, its on its side.


----------



## fitterman1

Profkanz said:


> Negative rake is common for brass which tend to be grabby with positive rake cutters. Its why we have to dub the cutting lips on twist drills when drilling brass.


Works very good on cast iron also.


----------



## Profkanz

Brento said:


> When talking about the negative rake are you talking about the back?


Negative rake is when the top of the tool slopes down toward the tip. 3-6 degrees is often used.


----------



## Profkanz

This is the correct orientation. 

Right hand cutting tool (cuts from the right). Negative rake slopes down from the shank to the tip (tool nose).


----------



## Brento

So from what i am hearing that tool is best for brass and copper. I am going to be grind a few tools for basic turning on this lathe for steel aluminum and brass. Maybe for cast iron as well. Now which type of tool is best to make. A knife or the basic right hand turning tool like the one i showed. It is a small lathe so i wont be taking big cuts. So what type of radius is a typical size a 1/16th?


----------



## mikey

Brento, that is an interesting looking tool. The shape of the tool is up to the user but the rake and relief angles DO matter. Insofar as what material this tool was meant to work with, I have no clue. Tools for brass typically have zero to 5 degrees of positive side rake to reduce the tendency to dig in. Plastics work best with very positive rake tooling. This tool will generate very high cutting temperatures so it isn't for stainless or even mild to medium carbon steels. Cast iron responds best to higher side and back rake similar to stainless, not negative rake, in my experience. So, again, I have no idea what the maker of this tool was thinking or what material it would be optimized for.

Then there is the possibility that he did not understand lathe tool geometry.

If you wish to turn brass, I highly recommend you use zero side and back rake. Grind a general purpose shape with about 12-15 degrees of side and end relief but leave the top flat. Put a 1/32" nose radius on it and I guarantee you this tool will not dig in and will leave a mirror finish.

For steels, I would definitely include positive side and back rake. For general use, a RH general purpose tool with 15 degree relief and rake angles works well (like our square tool). This tool will work with mild and medium carbon steels, aluminum, brass and plastics. It isn't perfect for any of them but it will work well with all of them.

You are going to find that the smaller the lathe, the more important tool geometry becomes. Take some time to read through the explanations of the various features on the tools in this thread so that you understand what does what. If you really want your tools to work well, you must grind them to do what you want them to do. I've put enough in this thread to give you all the answers you need. If that is not enough then sing out and we'll clarify it further.


----------



## fitterman1

Profkanz said:


> This is the correct orientation.
> 
> Right hand cutting tool (cuts from the right). Negative rake slopes down from the shank to the tip (tool nose).


What you're saying is correct, but you wouldn't find that tool in my arsenal.


----------



## Brento

Wasnt there a pinned post in here for all of the information explaining both the knife and general purpose right hand tool? Also i have this cheat sheet that i was wondering if it was safe to go by for making the tools.


----------



## fitterman1

By all means, you cant go wrong.


----------



## Brento

Another question is could you get away with using a cut off wheel in a dremel tool to cut these angles out instead of grinding.


----------



## Brento

I just went back and found the 3 pdf’s it looks like my cheat sheet is the same in the pdf so thats good. Now i saw an example of a roughing and a finishing tool. I noticed the roughing tool has a bigger radius. Should i go to like a 1/16 radius for a roughing tool?


----------



## Brento

I also should throw in the reason i ask about using a dremel tool is bc i am working with 3/16 tool bits right now and at most 1/4 in a month or so.


----------



## Brento

I am marking out my aluminum cutter for the cuts and i am working on the back rake. 35 degree seems very big for a back and side rake. Is that a little much?


----------



## ttabbal

Brento said:


> I am marking out my aluminum cutter for the cuts and i am working on the back rake. 35 degree seems very big for a back and side rake. Is that a little much?



I think it's just the back rake on the top of the tool that is that high. It looks like a lot, but it does work well.


----------



## Brento

@ttabbal


Is that right looking? The base or the protractor is the top of the tool.


----------



## ddickey

That looks like the end relief.
You want the back relief at 35°.


----------



## Brento

Maybe i am backed at the wrong side but the protractor base is sitting on top of the tool. When i cut the back rake i would be looking at the side of the tool to cut it which is why the tool is on its side. So am i on the wrong angle?


----------



## ttabbal

The way I grind back rake is to put a line on the grinding rest. It is measured against the platen of the grinder, away from me and to the right of the belt. Align the tool with the angle on the table, press into the belt. 

If the tool side is facing the camera, I think you are going the right way. If it is your first tool, the high angle is probably not the best choice. Start with a lighter angle like 15 degrees. It will still cut well on aluminum.


----------



## Brento

If you are looking at the picture the top of the tool is facing left of the camera so the view we are looking at is the right side of the tool. I want to do it right so i am not afraid to cut the 35 degrees i just want to make sure i am measuring it right.


----------



## Brento

I also do not have a grinder with a platen much less a sturdy one. My plan is to put the tool in a vice and take my dremel tool and take a grinding wheel and grind it in that way. I was also thinking of taking a very thin cut off wheel to get rid of most of the material and then use the grinding wheel to bring it in. The bits are also 3/16 so they are tiny. Bc of that i may actually go to like a 18 degree or maybe 20 do to the size of the bit.


----------



## ttabbal

I see. I expect that would work, particularly on a smaller bit like that. Particularly if you are planning on working with aluminum for now, don't worry about the angle too much. You can almost cut aluminum with an unground bit.  

Try to get a square tool grind with about 15 degrees on most sides, maybe more for the top rake. Then hone it nice and sharp. It will cut aluminum like butter.


----------



## Brento

Thanks @ttabbal i am also making a cutter for brass and steel. After they are done then i am going to make the same tools again but i would like to make them for roughing. For a boring bar would you follow the same principle as the typical turning tool for all of the angles? This is the little guy i am making them for.


----------



## mikey

Brento said:


> I also do not have a grinder with a platen much less a sturdy one. My plan is to put the tool in a vice and take my dremel tool and take a grinding wheel and grind it in that way. I was also thinking of taking a very thin cut off wheel to get rid of most of the material and then use the grinding wheel to bring it in. The bits are also 3/16 so they are tiny. Bc of that i may actually go to like a 18 degree or maybe 20 do to the size of the bit.



Brento, I highly recommend you buy a bench grinder or belt sander to grind lathe tools. They are the right tool for the job and will allow you to grind your tools safely and efficiently. Your tiny lathe will require tools that cut with very low cutting forces and you need control to create them. Can you do it with a Dremel? Possibly, maybe ... but I could grind exactly what you need in probably under a minute on a belt sander.

Please understand that I'm not trying to discourage you. Just trying to give you a heads up - there is a better way.


----------



## ttabbal

Brento said:


> Thanks @ttabbal i am also making a cutter for brass and steel. After they are done then i am going to make the same tools again but i would like to make them for roughing. For a boring bar would you follow the same principle as the typical turning tool for all of the angles? This is the little guy i am making them for.



Neat little lathe. @mikey has a good point about wanting low cutting forces on a little machine like that. Before you go too nuts grinding lots of different tools, try a 15 degree square tool. It will cut most materials well and even do a good job roughing while still shaving tenths. For brass, I think you want a low back rake angle. I'd have to check again as I don't work with brass. 

I have never used an HSS boring tool. I suspect my internal threading tool is probably the same idea, but with the cutting faces ground like a turning tool. For stuff that small I usually go for micro 100 solid carbide though. 

The thing I think might be difficult with a Dremmel would be getting flat faces to hone. Getting the tools sharp will be harder. Maybe you're better with a Dremmel than I am.. My work with them tends to be on the rough side.


----------



## Brento

@mikey @ttabbal i want to get a bench grinder but funds are maxed right now after buying this lathe i have a belt sander base but i need a motor to get that going. For making a tool with lower cutting forces should i just make the 15 degree tool? Is the 15 degrees on all sides?


----------



## Gaffer

I've only read the past few posts on this thread, but maybe this will help you visualize the various rakes and their associated angles depending upon the material being turned.


----------



## Brento

This is another tool i found with the lathe.

top view
	

		
			
		

		
	



Left side
	

		
			
		

		
	



Right side
	

		
			
		

		
	



From the front view
	

		
			
		

		
	




@Gaffer i have that download and i have the cheat sheet for the angles but the 35 just doesnt look right when im trying to mark it out


----------



## KevinM

Yes, the 35 degree back rake makes the tool bit look a little comical.  I was sure that I was doing it wrong but that angle is best for aluminum.

Looks like I got carried away with the front relief.


----------



## ttabbal

Brento said:


> @mikey @ttabbal i want to get a bench grinder but funds are maxed right now after buying this lathe i have a belt sander base but i need a motor to get that going. For making a tool with lower cutting forces should i just make the 15 degree tool? Is the 15 degrees on all sides?











						Models for grinding HSS Lathe Tools
					

I suspect that the guys who really want this info will read the whole thing, mine it for the stuff that matters to them and then create their own document.




					www.hobby-machinist.com
				




There is a PDF with a lot of info there. So you can see what the tool looks like and so we can all use the same language to describe things. The required into for a "15 degree square tool" is all there, just adapt things to your grinding style. The photo you show of the tool that came with the lathe has a positive rake. That is commonly used on brass, but I wouldn't suggest it for anything else. Have you been sent the model tools? @Z2V has been coordinating that. You can make some models of your own to reference as you go. 

The tools that came with the lathe might work well. But they are likely to be confusing if you compare them to what we are doing here in the thread. Ignore them for now, we can go over them later and explain why someone might make them that way, but start with a "known good" setup that matches what we are doing. That way, we can help more effectively. Start simple, make one tool, use it, and go from there.


----------



## Brento

@KevinM that is exactly what i wanted to see so yes i was measuring it right so im happy.


----------



## Brento

I think i will make a general purpose tool but out of the knife tool. I think that will be the most useful.


----------



## Brento

Another question is what should i cut for plastics like nylon and delrin?


----------



## WobblyHand

For now, just use the aluminum tool.  If very sharp, it will work well.  Honing the tool makes a very big difference.  We are talking slice your finger by just looking at it sharp.  Ragged edges won't leave a nice finish.

The square tool is the most practical tool to grind first.  It has lots of uses and is versatile.


----------



## mikey

Brento said:


> @mikey @ttabbal i want to get a bench grinder but funds are maxed right now after buying this lathe i have a belt sander base but i need a motor to get that going. For making a tool with lower cutting forces should i just make the 15 degree tool? Is the 15 degrees on all sides?



There are some bench grinders on CL in your area. Not sure where Vernon is but here is a brand new Porter Cable for $35.00.

Of all the tools we have discussed in this thread, the square tool is the most versatile. Yes, tools with a geometry optimized for a specific material class will work better but you will have a hard time finding a tool that will cut almost anything as well as a square tool. That includes aluminum, delrin and other plastics, brass, stainless, mild and medium carbon steels. What's more, it was actually optimized for a little Sherline lathe so it will work on your lathe, too. 

If I were you, I would go find a bench grinder. Then go to this thread; it tells you exactly how to grind a square tool. 

Another option is to have @Z2V or @ttabbal grind a 3/16" tool for you to get you started. I have seen their work and it is as good as I can do.


----------



## mikey

Brento said:


> This is another tool i found with the lathe.
> 
> top view
> 
> 
> 
> 
> 
> 
> 
> 
> 
> View attachment 355775
> 
> Left side
> 
> 
> 
> 
> 
> 
> 
> 
> 
> View attachment 355776
> 
> Right side
> 
> 
> 
> 
> 
> 
> 
> 
> 
> View attachment 355777
> 
> From the front view
> 
> 
> 
> 
> 
> 
> 
> 
> 
> View attachment 355778
> 
> 
> @Gaffer i have that download and i have the cheat sheet for the angles but the 35 just doesnt look right when im trying to mark it out



I am now convinced that the guy who ground those tools had a different understanding of tool geometry than I do. Doesn't mean he is wrong but negative rake tooling on a very small lathe doesn't work well. Negative rake tools create nice finishes but also create huge cutting forces that require a lot of rigidity and power to utilize.

If I owned a little watchmaker's lathe, I would be using positive rake tooling and gravers.

If you do not have a solid understanding of the different tool angles, go here and read this stuff first:

https://www.machinistblog.com/grinding-lathe-tools-on-a-belt-sander/
https://www.machinistblog.com/grinding-lathe-tools-on-a-belt-sander-part-2/
https://www.machinistblog.com/grinding-lathe-tools-on-a-belt-sander-part-3/


----------



## Brento

Im going to work on grinding one up tonight ill start with a square tool i guess. So when is a knife tool best used.


----------



## WobblyHand

When the square one doesn't do the job!    Believe me, the square tool is pretty versatile.


----------



## ttabbal

I don't use the knife much. It works, but I haven't found the right way to really get it to work as well as I think it should. I use various versions of the square tool for almost everything. The 15 degree is so versatile I can get a good finish on almost everything. I grind up special versions for a few things. Most steels work well, other than 1018, that stuff hates me.  

I think the only small bits I have (<3/8) are harbor freight M2. I'll make you one if you need it. I have a set of model tools I can send as well.


----------



## Brento

I think i will be good @ttabbal i know the concept. Back to my original question i just wasnt sure how the 35 degrees was suppose to look or if i was measuring the angle right but now that i have seen the tool i know im measuring it right. I will make the square tool but i am making specialty tools as well bc im just that type of person. I like to challenge myself.


----------



## Brento

Cut this this morning i have not done the radius bc i will use my diamond cards to bring it in. This is the generic square tool. The side angle towards the back isnt perfectly ground straight but the grinding wheel needs to be replaced and the bit is so tiny to hold. The cutting edge is straight just towards the back is like sloped


----------



## Brento

This is the aluminum version. I went to a 22 degree angle to lower the cutting force a little on the back rake.


----------



## ttabbal

Particularly considering they were ground with a dremmel, they look good. Hone them up and make some chips.


----------



## Brento

These were not from the dremel. From a grinder. Im going to try a dremel grinder on the steel and brass version later in the week.


----------



## tmenyc

Brento, that looks good!  

Somehow I missed the instruction probably almost two years ago about getting a white AO wheel for tool grinding instead of the grey one. I posted about this choice some days ago (here...), after seeing a Blondihacks video where she ground a tool using a white wheel that got me thinking...before I knew enough to start asking why I didn't know about that...

So I bought one from Lee Valley, a Norton 3X 80 grit, acting on the advice of members I respect here, and WHAT A HUGE DIFFERENCE! Ground the first square tool today. It used to take me close to an hour, burnt fingers and a ton of dust to bludgeon a tool into submission. Today, this one took around 20 minutes start to finish, no faceting, just let the grinder do its thing. Much much cooler, much quicker and easier. Dressing still creates a bit of dust, but nothing like before. I've always liked the result of grinding my own HSS tools, but it was painful, and I hadn't realized why until now, and now it's fun! Next up, a cobalt square tool that I can make my main tool. 

Note: this is fresh off the grinder, no cleanup, NR or honing yet. The color change is just color, not faceting. There are tiny bits of microcloth stuck on the lead edge, too. Promise.
Thanks again, Mikey!

For the all-purpose cobalt tool, should my NR be closer to 1/32" or closer to 1/64"?

Tim


----------



## Brento

Ill have to get one of the white stones. I used a worn out great wheel on a grinder but im going to try a dremel and cut off wheel bc these bits are so tiny that it may work a little better in a way. When i buy a grinder i plan to find a decent diamond wheel for carbide touching up, and the white wheel and then i will change them around and set up a buffing wheel on the other side. Id use a belt sander but i need a motor to go with the belt sander i picked up from my old job that they were going to scrap. It was my first time making a tool minus a threading tool. My bits are m42 so i believe it already has cobalt in it.


----------



## mikey

tmenyc said:


> Brento, that looks good!
> 
> Somehow I missed the instruction probably almost two years ago about getting a white AO wheel for tool grinding instead of the grey one. I posted about this choice some days ago (here...), after seeing a Blondihacks video where she ground a tool using a white wheel that got me thinking...before I knew enough to start asking why I didn't know about that...
> 
> So I bought one from Lee Valley, a Norton 3X 80 grit, acting on the advice of members I respect here, and WHAT A HUGE DIFFERENCE! Ground the first square tool today. It used to take me close to an hour, burnt fingers and a ton of dust to bludgeon a tool into submission. Today, this one took around 20 minutes start to finish, no faceting, just let the grinder do its thing. Much much cooler, much quicker and easier. Dressing still creates a bit of dust, but nothing like before. I've always liked the result of grinding my own HSS tools, but it was painful, and I hadn't realized why until now, and now it's fun! Next up, a cobalt square tool that I can make my main tool.
> 
> Note: this is fresh off the grinder, no cleanup, NR or honing yet. The color change is just color, not faceting. There are tiny bits of microcloth stuck on the lead edge, too. Promise.
> Thanks again, Mikey!
> 
> For the all-purpose cobalt tool, should my NR be closer to 1/32" or closer to 1/64"?
> 
> Tim
> 
> View attachment 355916
> View attachment 355919
> View attachment 355918



Really nice job, Tim. That's going to be a good tool.


----------



## Brento

Tonight i honed the tools i made earlier today. I think they came out good. The generic square tool has a 64th radius and the aluminum tool i got a little carried away and it ended up being a 32nd i also started with a coarse diamond card and then went to fine followed by extra fine. When you guys hone do you use a diamond stick or do you use a stone? I always thought for honing you use a diamond card or stick.


----------



## tmenyc

Looks good!  

Mikey, 
I know you told me way back, but I can't find it, about what angles to use for acetyl and ebonite (also known as vulcanite, it's compressed organic hard rubber, still used for smoking pipes and saxophone/clarinet mouthpieces and, for me, replacing vintage fountain pen parts with original materials). I know you said that anything I use for aluminum would work, but now that I'm able to grind much more easily, I could make a tool and dedicate it to the softer stuff. What do you recommend? 

Many thanks, 
Tim


----------



## ttabbal

Brento said:


> Tonight i honed the tools i made earlier today. I think they came out good. The generic square tool has a 64th radius and the aluminum tool i got a little carried away and it ended up being a 32nd i also started with a coarse diamond card and then went to fine followed by extra fine. When you guys hone do you use a diamond stick or do you use a stone? I always thought for honing you use a diamond card or stick.



Looks good. The pics are a little grainy when zoomed, but that's difficult to deal with for most simple cameras. The radius should be fine. It increases cutting forces a little, but you need some. Without it you get a finish that looks like a vinyl record. A bit like if you used a threading tool for everything. The nose tends to be a bit weaker as well. I use diamond cards for honing and the radius. Stones and sticks can work as well. The catch I would have with stones is when they start wearing down they get a bow where they get used the most. The cards are cheap enough that tossing them when the grit wears down isn't a big deal. Good stones cost a lot more.


----------



## Brento

I have cheap ones that came in a set of 3. I think from amazon


----------



## mikey

tmenyc said:


> Looks good!
> 
> Mikey,
> I know you told me way back, but I can't find it, about what angles to use for acetyl and ebonite (also known as vulcanite, it's compressed organic hard rubber, still used for smoking pipes and saxophone/clarinet mouthpieces and, for me, replacing vintage fountain pen parts with original materials). I know you said that anything I use for aluminum would work, but now that I'm able to grind much more easily, I could make a tool and dedicate it to the softer stuff. What do you recommend?
> 
> Many thanks,
> Tim



Having zero experience turning this stuff, I don't know what would work best. This will be trial and error but I have a good idea of what would be needed. However, rather than just coming out with it, this might be a good exercise in designing a tool.

Vulcanite/Ebonite, from what I can find on the web, is a hard sulfurized rubber formed under high pressure with a *softening temp of only about 160 deg F*. That means that we have to keep the cutting temps really, really low. That suggests you need to turn this stuff at low speeds and somewhat higher feeds and that your tool MUST be optimized for lowering cutting temps. It must also be very sharp and you have to keep the tool moving when you turn the work to reduce temps. A stream of low pressure compressed air at the point of cut might also be helpful to keep temps low.

Rather than me telling you what I would do, why don't you guys tell me what YOU would do to meet the needs of the material? The shape of the tool can be a general purpose shape but what do you do with the relief and rake angles? More importantly, WHY are you choosing the angles you're choosing?


----------



## tmenyc

Mikey,
I love it !  And yes on the low pressure compressed air, have that already.  I generally push around 20psi at the point of cut.
I guess I would want to maximize clearance to keep it cool and clear the work away, and to raise back rake.  Maybe 20 deg side and end relief and 40 deg rake? 

Tim


----------



## mikey

Tim, our focus should be on lowering cutting temperatures; increasing side rake will do that most effectively. Increasing back rake will also lower cutting temps by accelerating chip flow and thinning the chip thickness. Leaving side and end relief at about 15 degrees will work fine. I would boost side rake to about 20 degrees and use a back rake of about 15-18 degrees. This amounts to an aggressive amount of rake and will definitely improve chip flow. Since most of the heat from the cut will go out with the chip, this should work well. I would keep the nose radius around 1/64". 

Give it a try and remember to use your edges for finishing. The area just behind the nose radius on either the side or end will shear a really nice finish.


----------



## tmenyc

Interesting, so not based on the aluminum-use tool with severe back rake. I'll try it!
Many thanks.
Tim


----------



## mikey

I suggest you try this first and see how it works. If it cuts too hot then use more rake.


----------



## Brento

For a parting tool does any of the turning tool angles matter? I know you want to have a end cut angle so you can hopefully have a clean part on the back with no tit but is there anything else like the end relief?


----------



## mikey

I suggest a relief angle of 7 deg under the cutting edge. Hone the top flat.


----------



## Brento

Ok would a 2 degree end cutting angle be fine to get the **** cut off hopefully? Thickness be an 1/8" be ok most likely?


----------



## mikey

I would grind the end straight across.  I've tried them all and a straight tip works best for me. The way to tell what works best for you is to try it and see.

I highly recommend you consider a P1-N or P1 blade. When rigidly held, they will cut almost anything your lathe could possibly hold. I use a P1-N almost exclusively on my Sherline lathe to cut up to 2" dia. work pieces. Keep in mind that parting tools are actually form tools; the wider the blade is, the higher the cutting forces will be. The key, of course, is to mount the blade in a rigid holder. 

If you can rig it, mount it upside down and in the rear of the work piece. I can almost guarantee this configuration will make parting a breeze.


----------



## Brento

Do you happen to know the size shanks those blades are? I am constrained to 1/4 at the most.


----------



## Brento

It would appear they they are 1/2 inch so they would not work. Now all of this would be fixed if i had the flip up tool post and some gravers lol


----------



## mikey

Gravers are simple to make. The tool rest is a bit more complicated but not too bad. Look up WR Smith on the Sherline website.


----------



## Brento

Im prob going to end up buying the Derbyshire flip up rest at some point. I made to cut off blades. One in a 1/4 but i think came out kinda terrible and 3/16 .040 blade that is a little longer to reach in. They are not honed yet. On the parting off side should i put a bit of a relief from the cutting edge as well so there is not rubbing?


----------



## mikey

Most parting blades have a 5-7 deg relief on both sides of the blade.


----------



## Brento

Ok ill try to cut that in atleast on the 3/16 parting blade.


----------



## Brento

So i got to do some cutting on aluminum. The aluminum tool cut nice.





I am not use to having to move the tool post around between facing and turning for cutter clearance. After i tried out the generic cutter and i admit that i liked it alot better then the Aluminum tool.


It seemed to cut much nicer and a better finish. Now for my problem that i had. 
	

		
			
		

		
	




The parting tool chattered like crazy as i cut. I ended up stalling the spindle once. (Did not smell good). Bc of the chatter the headstock would come loose a little also. So im guessing the cutting pressure is way to high? I decided to try cutting with some Cool Tool 2 cutting oil and the chatter was a little better. As i got to the center that chatter got even better so i am also curious if i was going to fast at first?


this is the finished parting tool. I did hone it, this is after i was done cutting. I have a 1 or 2 degree at the tip hoping to make the parted off part not have a tit. Well it did have a tit so i am curious if i should just go to a square nose? It also tapered the part alot as i cut the part off. I am assuming it was due to the chatter as well. What can i do to help this parting tool perform better and so i am not chattering so much?


----------



## mikey

Brento, grinding the tool at an angle will tend to steer the tool in the cut when the body of the tool is thin like yours is. This results in a concave or convex cut. You will find that grinding the tip straight across will work better for you. 

As to why you're chattering, that has so many causes it's hard to list them all. However, one thing that is for sure contributing is the grind on your tool. Here is a close up of the tip:




See how the front profile is curved when it should be straight? The top of the tool is also reflecting a lot of light, which suggests the top of the tool is not flat or sharp. 

One reason the chatter got better as you got closer to the center is because the surface speed drops as you approach center. This happens at about the inner 1/3 of the way in. The response to chatter is the same when parting or turning; reduce you speed and/or increase your feed. But first, try correcting the geometry of your tool.


----------



## Brento

Thanks mikey. I did have it honed before i used it. That picture is after i used it. I will touch it up today on the grinder as i make another cut off tool today but on the other side of the bit so i can get closer to the chuck. I will also obviously hone it again. Wondering if i should add more of a side cut relief or maybe a side rake? It seemed like it had some high cutting forces. I could be wrong. I guess i will do one at a time.


----------



## brino

@Brento,

For me the thing I see as the most likely problem is tool flex.
Both of the below contribute to tool flex.

1) tool profile
My regular-use lathe bits are 3/8", but I believe you stated earlier (or in another thread) that due to your small lathe and tool-post it was easier to use smaller tool bits. That means that by the time you grind that thin cut-off tool profile, there's really not much "beam strength" in that tool. The cross-section of the tool will only be 3/16" tall by the width of the tool you ground 0.040".

2) tool length
If you are trying to part off a work-piece that is 1" diameter then obviously you need a tool with a minimum cutting length of 0.5". From here it looks like your parting tool is probably over an inch long, but you don't really need all that length for the current operation. I understand that you'd like to have one parting tool that you can use for most diameters of work-piece that you need to cut, however it may be worth having multiple tools with different parting lengths. Start with the shortest, and then move up as the cut progresses. Of course this means a bunch of hassle changing bits mid-operation and having to very carefully align them to the existing cut.

Both of the above would be helped immediately by using an adjustable parting tool and holder.

1) Compare the cross-section of what I believe your tool looks like compared to an "off the shelf" parting tool.



The blade on the left is based on the drawing from the first amazon hit on "P1-N or P1 blade" that @mikey recommended earlier:
https://www.amazon.com/HHIP-Parallel-Cut-Off-Blades-Various/dp/B01IAT7VXG
Neither drawing shows the taper or side relief, but they give the point.....

2) With an adjustable parting tool you can have only the small amount of stick-out you need for the current operation....in fact you can start the cut-off operation with minimal stick-out and then adjust the tool out further as you cut deeper.

Personally I have found parting tool strength to be a major factor in chatter. I originally thought that having a thinner parting blade would reduce chatter by reducing cutting forces, but what I found is that a wider blade tends to chatter less. To me it implies that the tool flex is a bigger factor than reduced cutting forces of the thinner blade.

-brino


----------



## Brento

Wouldnt a thicker blade make a bigger cutting force as well though? I have to grind another cut off blade so i can maybe make the blade .100 thick? And i will make the cutting tip straight across not at an angle. Should i put a rake on the cutter? Anything else to help the profile? Of i gotta cut a part off and flip it over to clean it up then well thats what i have to do.

The tool post i have now i can only take 3/16 bits. I can fit a 1/4 in but then i have to grind alot off the top to get the bit on center. I am getting a new tool post set up made from Tom and he said he could fit 3/16 and i think a little bigger. I will do a little digging to see if i can find an adjustable parting blade like they have. I can only use hss i believe on this lathe so ill see how the adventure goes. Thanks for the help.


----------



## Brento

So i was at it again tonight the chatter was better looking today on the part then yesterday the chips i think look better as well. 
	

		
			
		

		
	



I made a new blade up today that is .100 thick for maybe less flex.



I know the relief on both sides are not the same. My dads grinder doesnt have a rest to try and grind on so its all by hand. I had a small issue where it was cutting about .02 up the blade, so i took my dremel with a stone and dressed it to fix it up. I then rehoned that side and went back at it. This tool post is hard to set up on center so im not 100% sure if that is all of my problem still or not. I should hopefully have my new tool post soon and i will do more tests. I liked the finish on this cutter better then yesterdays.
Todays


Yesterdays


At this point i also have to take into consideration that i doubt i will be cutting and parting off stuff over a half inch as much? The stock is maybe around .600 so i have that going for me. I tried slowing the lathe down the slowest i can and but boy is the chattering loud. Not sure what else i can maybe do at this point.


----------



## mikey

Your tool looks a lot better and I'm not surprised it cuts better, too. 

As for chatter, remember that if the tool chatters you need to slow the speed and/or increase the feed. If you are running at the slowest speed your lathe can run, increase the feed rate. Of course, chatter can also come from many other sources than just your cutting conditions (speed, feed). The lack of rigidity in a small lathe, not being dead on center height, tool not being precisely perpendicular to the work all come to mind. 

Parting is a problem for a lot of folks. You just need to sort through all the possible causes and find what works best for your situation. Having a good tool really helps.


----------



## Brento

Thanks mikey i cant really push harder on the feed or due to the lathe rigidity. I can feel the vibration in the head stock and i dont want to stall out the spindle. Is there a cheating way to maybe get past part of the cut off tool. Like say if i made like a threading tool for example but gave it a nice radius and cut into the part or made a little slot and then used the parting tool?


----------



## mikey

Is it possible to rear mount a parting tool on your lathe? Does the cross slide have T-slots or can you adapt the cross slide to accept a rear mounted tool post? If so, that would be a really good option for you. A rear mounted parting tool post with a parting tool mounted upside down, with the tip set to center height, will part far better than from the front on a small lathe.


----------



## Brento

I have 2 t-slots on my compound so i could swing around and do that. My problem is the tool post block is mounted through a bolt and the tooling slot does not have alot of room to move. I can try that tonight and see what i can set up.

I also want to ask and say i was highly mis-informed i have m42 hss blanks and i always thought the m42 was for the amount of cobalt in the part. I found now that m42 is for stainless and high nickel parts. I ordered 10 bits of m2 which is recommended for steel, brass, and aluminum. I am still tempted to maybe make a pre parting tool cut off as i stated in my last post but i am not sure if that would help alot or not.


----------



## Brento

My qctp from tom is done and tge food news mikey is i can turn the parting tool upside down. Should i make a rake for the top of the cut off tool? Maybe like a 10 deg?


----------



## mikey

Brento said:


> My qctp from tom is done and tge food news mikey is i can turn the parting tool upside down. Should i make a rake for the top of the cut off tool? Maybe like a 10 deg?



No, you just use your standard parting tool but mount it upside down. Be sure the tip of the tool is on center height and that the tool is precisely perpendicular to the work piece. Part by backing the cross feed handwheel out, pulling the tool into the part.


----------



## mikey

Brento said:


> I have 2 t-slots on my compound so i could swing around and do that. My problem is the tool post block is mounted through a bolt and the tooling slot does not have alot of room to move. I can try that tonight and see what i can set up.
> 
> I also want to ask and say i was highly mis-informed i have m42 hss blanks and i always thought the m42 was for the amount of cobalt in the part. I found now that m42 is for stainless and high nickel parts. I ordered 10 bits of m2 which is recommended for steel, brass, and aluminum. I am still tempted to maybe make a pre parting tool cut off as i stated in my last post but i am not sure if that would help alot or not.



M42 is a HSS tool with 8% cobalt. It can be used for standard work but excels for cuts in materials that are either really abrasive or in high heat situations. Your lathe is not capable of generating excessive heat at the point of cut so a standard M2 bit will do for almost anything you're likely to encounter.


----------



## Brento

Ok well i ordered m2 bits. I had m42


----------



## Aukai

If you have an M42 bit, and use it on a lesser material than it was designed for, will that make a difference in the performance of the bit?


----------



## Brento

That is in a way what i am curious about.


----------



## Aukai

In my mind, I have been working on an assumption, but never asked the question.


----------



## mikey

Aukai said:


> If you have an M42 bit, and use it on a lesser material than it was designed for, will that make a difference in the performance of the bit?



No, there is no performance difference.


----------



## Aukai

Good to know I got away with an "assuming"


----------



## tmenyc

Mikey et al,
Here is the tool intended for cutting ebonite and other soft materials, per our discussion in posts 1503 and 1504. 15 deg side and end relief, 17-18 deg back rake, and 20 deg side rake. Took awhile to remove all the rake material. The shining at the edges is from honing flat vs the curved grinding wheel. Yes there is one facet in the northwest corner of the top, but I didn't want to risk the rest of the cut to clean that off. And yes there are a couple of nicks on the edges behind the top.  They annoyed me too, my bad. 
It's incredibly sharp. 
I'll try to take a test cut this tomorrow. 
Curious about your and others' thoughts. 

Tim


----------



## tmenyc

Aukai said:


> Good to know I got away with an "assuming"


Yep...doesn't happen often!
Tim


----------



## mikey

Proof is in the pudding, Tim. Cut with it and you tell us. The tool itself looks good.


----------



## tmenyc

Yep,  as soon as I can !
Tim


----------



## mikey

Tim, I forgot to mention that you need to put a small nose radius on this tool. 

It is clear that something has happened to greatly improve your tool grinding. I think you mentioned the grinding wheel might have helped a lot but whatever it is,  you have come a long way, Sir!


----------



## tmenyc

Mikey, 
I forgot to mention that I haven't put a NR on it yet!  

And thanks for the comment. It's all because of your patience and teaching. I think I'm finally learning what it all means, not just the numbers. Clearly worth learning. 
Tim


----------



## mikey

tmenyc said:


> I think I'm finally learning what it all means, not just the numbers.



This is also clear to me, Tim. You're doing good!


----------



## tmenyc

OK...well, it works, and well. I normally use an IPR of .0062 @ 450 rpm for 12L14 with my square tools on my Logan, and 750 for roughing. I played a. little with IPR, @450 rpm, and it seemed immediately happier at .0077 IPR, also @450 rpm. My Logan is never comfortable turning deeper than .015 at a pop, and I was pretty leery of turning the ebonite more than .005. But that worked well, as did .010. The pictures show the two depths of cut. It parted off really easily, like cutting into a frozen stick of butter. I didn't want to cut into a longer piece, stuff is a bit dear, so only did about a half inch of .500 wide at at time and didn't bother supporting it. But having drilled the stuff before, I am really happy it didn't just crumble under the blade.
First pic shows the faced end, second the piece of ebonite, third the chip. The thinner chip is .005, thicker is .010. Don't think I'll be going deeper.
I must admit, everyone has said turning this stuff is nigh unto impossible. Not true.

best,
Tim


----------



## mikey

Can you show us the section you turned? It's possible we can improve the cut if we can see what the current geometry is doing.


----------



## tmenyc

Here it is...turned .010 deep, .0077 @450. This time it was supported. Quite smooth. You can see the cut rings, but it polishes easily, and I predominantly create parts you'll never see.. Ebonite is compressed granular slurry, so this is what it looks like.
Tim


----------



## mikey

You might try taking a very light cut with the end cutting edge, just behind the nose radius. Turn the tool tip towards the chuck and touch the work just behind the nose radius and see what happens. You should be able to take a 0.001" cut and improve the finish. Be sure the tip is on center height.


----------



## tmenyc

Shall do, thanks. Tomorrow evening. 

Tim


----------



## tmenyc

Ok, turned down .002, with LA positive. One thou did nothin. Much cleaner! I won't even need to polish this!

thanks so much!
Tim


----------



## Brento

So what would you say a much smaller radius for the tip of the tool to keep that finish?


----------



## mikey

Yeah, that's better.


----------



## mikey

Brento said:


> So what would you say a much smaller radius for the tip of the tool to keep that finish?



His nose radius is already pretty small. Tim is using the end edge to shear the cut; see the shaving? That is what you get when using the end edge just behind the nose radius, a shearing cut. This produces a nice finish in almost all materials and can be especially effective with light passes.


----------



## Brento

That is nice to know i will remember that


----------



## Fermic

Hello everyone,

I have been having trouble with 2 pre-cut HSS tools after cutting some alu 6061 : one is dulled and one is broken and poor regrind was tried on it.

The offset cutter, I can try replicate the grind with the intact left hand.
The turning cutter looks not very ground.

My bench grinder is a brand new Dewalt 6-inch.

My pictures


----------



## Aukai

Do you have diamond cards to re hone the edges instead of grinding? Did this work well when you were cutting?


----------



## Fermic

Aukai said:


> Do you have diamond cards to re hone the edges instead of grinding? Did this work well when you were cutting?


Sadly not, I only have one combination india stone. Which grit I should get for the diamond card ?

They were working fine before I pushed too far at cutting alu.


----------



## Aukai

Can you get these up there?


			https://www.amazon.com/DMT-D3EFC-Dia-Sharp-Extra-Fine-Diamond/dp/B00006IIO3/ref=sr_1_2?dchild=1&keywords=diamond+sharpening+card&qid=1614824463&sr=8-2


----------



## Brento

I can say the cards Aukai suggested work good i have a set of them. I also pick up the ezelap sticks and get them today.


----------



## Fermic

Good to hear, I'll start with these cards in this order.


----------



## Aukai

Find a good lapping oil too to keep the cards clean while in use. I use Trend, but it is said to be expensive, and other light oils can be used but I cannot comment on how good that is..


----------



## Fermic

Aukai said:


> Find a good lapping oil too to keep the cards clean while in use. I use Trend, but it is said to be expensive, and other light oils can be used but I cannot comment on how good that is..


Seems to be expensive, indeed. I'll start looking around for this such oil.


----------



## mikey

Water actually works best to flush metal debris off diamond stones in use. Just keep the surface wet and rinse it off before drying it and storing. If the surface gets crud on it, clean with a powdered cleanser like Ajax, Comet and others. Use a nylon brush, not a metal one, and scrub lightly.

Fermic, you should be able to restore the edge to your tool with the cards that Aukai recommended. Use the coarse, then fine, then extra-fine and only use light pressure. Diamond cuts really fast.

I do not use the kind of grind on your tool. The edge is extremely fragile in my opinion, and it looks like it has too little side and end relief so the tool will tend to rub. This makes taking deep cuts problematic. The nose radius is rather large so the tool will deflect more than it should, making accuracy a bit more difficult to achieve. The side and end edges on both tools are at a 90 deg angle so neither one can cut into a shoulder.

You would be better off grinding a general purpose tools as outlined in this thread. It will cut with lower cutting forces so it will work better on your little Emco. It will also be able to access shoulders and if you keep the nose radius small, you will also reduce deflection to a minimum and thereby improve your accuracy. 

I highly recommend you contact @Z2V and get your hands on the model tools he has. Copy them and make some tools like them from HSS. Then compare them to your purchased tools and you'll see the difference.


----------



## martik777

Are you people using import HSS or American brands like Rex, mo max etc. I find the import HSS too soft to be of much use and the American HSS almost impossible to buy locally.


----------



## Aukai

I keep my eye on Ebay, every once in awhile someone cleans out a garage. Not sure how that works for you up north.


----------



## martik777

I am 15 mins from the border so I can pickup from a USPS forwarder when the border re-opens


----------



## mikey

martik777 said:


> Are you people using import HSS or American brands like Rex, mo max etc. I find the import HSS too soft to be of much use and the American HSS almost impossible to buy locally.



All my daily user tools are from US makers but some are from ETM (Israel) and Japan and those are just excellent. The Chinese HSS bits are not bad. They don't hold an edge as long but I think they're fine in a hobby shop. If I was strapped for cash and needed HSS I would not reject a Chinese bit.


----------



## Watchwatch

martik777 said:


> Are you people using import HSS or American brands like Rex, mo max etc. I find the import HSS too soft to be of much use and the American HSS almost impossible to buy locally.



You can find old school American HSS on EBay for a few dollars a piece if you are patient. Mexican Mo Max is supposed to be good to go as well.


Sent from my iPhone using Tapatalk


----------



## Aukai

What size blanks are you, and Fermic using?


----------



## Fermic

Aukai said:


> What size blanks are you, and Fermic using?


5/16" HSS blanks for EMCO Compound or 3/8" if I can get my ass off to buy the needed material to make a plinth for my multifix so it can get under the center line.

Right now, that's the former one at this time.


----------



## Aukai

I'll keep an eye out, are you going to be shaping your own?


----------



## Fermic

Aukai said:


> I'll keep an eye out, are you going to be shaping your own?


Yeah, for alu and various metals. The pre-cut ones might be for cold rolled steel and definely NOT good with brass. Totally not cutting massive screw gouge in a brass rod.


----------



## Aukai

What happens when stuff gets mailed up there?


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## Fermic

Aukai said:


> What happens when stuff gets mailed up there?


No idea, he'll come back to me in a day.


----------



## Aukai

If you get mail from the US what is the procedure?


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## Fermic

Aukai said:


> If you get mail from the US what is the procedure?


I suppose that I'll make some tooling by basing on these models, perfectly as possible. Learning from the process, could be made easier with some angle references on the grinder plate. Then pass off these models to someone else in Canada.


----------



## riversidedan

mikey said:


> In a recent thread by @Darkbluesky, http://www.hobby-machinist.com/thre...tools-ideas-of-what-to-buy.62043/#post-511618, @ttabbal joked about sending me blanks to be ground into lathe tools ... he was joking! But it got me to thinking ... yeah, I know it's not a good thing when Mikey gets to thinking ... but it got me thinking that reading about how a tool is ground and having a decent tool in your hands that you can see and touch are two different things.
> 
> So, what if I ground a set of tools from 3/8" mild steel keystock (just to discourage some bozo from actually trying to cut something with the models) so people could hold it in their hands to look at. You could use them to plop onto your tool rest to see what the rest angles should be and maybe how your hands have to align to grind the tool. You could also buy some keystock and duplicate them for a permanent reference, and then pass them on to the next guy who wants to have a look.
> 
> I'm thinking of making *THREE* sets of these model tools and mailing them out to guys who are interested. We would need to figure out a list if there are more than three guys interested in seeing them, and YOU GUYS need to sort out how to keep track of these things. I would guess one to two weeks of holding time per person would be reasonable and the guy who has them would pay to flat rate ship it to the next guy on the list. Naturally, the only guys who can get on the list would be members of the HM forum.
> 
> As to which tools to include in the set, I'll leave that to you guys. We can discuss it here and see if we can come to some consensus. I will probably write a set of notes with details on how each tool is ground and why the angles are what they are and how you can modify them to better suit your needs; these notes would be posted to this thread.
> 
> I don't know if this is of interest to anyone but on the off chance that it is, let's talk about this and see if we can make it real. I'll spring for the keystock, grind the models and send them out. After that, you guys need to sort out how to get them distributed. The last guy on the list can hang onto them until some other HM member contacts them or you can send it back to me so I can do the same.
> 
> Let me be very clear about one more thing. The models will be of tools as *I* grind them for use in *my* shop on my lathe(s). It is one way, not necessarily the right way or the only way. My hope is that it will help you to find your own way of grinding tools that work for you.
> 
> Thoughts?
> 
> Mikey


I for one am new to the lathe game and think learning HSS tooling is an art and something Id be good at. like it or not have decided and already  have a set of HSS tooling  I will study and copy as a guide being Im more of a "hands on guy


----------



## Fermic

Update after getting these model tools from @Z2V and I have been able grind all them from HSS blanks ( except one that's ugly to me ).

The Square tool looks well done to me, the Knife tool is ugly because I have used one of my former brass/copper HSS tool and it looks more some of excrement looking than normal.
As for my threading tool, I also made it but I don't have the fishtail ruler to check the cutter shape. I could 3D print one quick for this.

My test cuts with 6061 at the top and 12L14 at the bottom.




The knife tool could be crap because I did grind from brass/copper hss bit to this.


----------



## DavidR8

Glad you got the models @Fermic!


----------



## mikey

Good job, Fermic! You did way better than I did when I started out.  You did a nice job on the square tool. The knife tool needs work but I would focus on learning to grind and use the square tool; it will give you the most mileage for now.

Your cuts look good and will get better as you learn to use these tools. Just from the pics, it looks to me like you need more speed for the aluminum.


----------



## Fermic

mikey said:


> Good job, Fermic! You did way better than I did when I started out.  You did a nice job on the square tool. The knife tool needs work but I would focus on learning to grind and use the square tool; it will give you the most mileage for now.
> 
> Your cuts look good and will get better as you learn to use these tools. Just from the pics, it looks to me like you need more speed for the aluminum.



Thanks to you with these models, I can grind my HSS blanks into these nice working HSS tool bits.

The knife tool, I am figuring how to use it as intended with my QCTP. I kinda got some spirals on the face of 12L14 when I faced it, I bet this tool isn't for roughing work.

For 6061 aluminium / aluminum, I spun the piece at 1000 rpm and cut it manually the fastest I could with the handwheel.
For 2000 rpm, I don't know if my worn tooth gear on the motor of my lathe will cause any problems for me, will revisit later.


----------



## mikey

Remember that the knife tool is intended to be a facing tool. It has other uses but it excels at facing. It will leave a near mirror finish in almost all materials. It will also work well when taking micro-cuts in thin material because it does not deflect much at all. It does not work well for normal turning; it does not have an end cutting edge to contact the work so it cuts with the nose radius and that leaves fine lines in the finish - not ideal. For most turning, use the square tool. If you need to take a very tiny facing cut with control, pull out the knife tool. 

I often turn aluminum at the max speed my lathe can run at, at least for pieces 3/4" OD or less. You will be surprised how well a good square tool cuts aluminum at high speeds. 

You will find that the typical calculations for rpm are just rough guidelines, especially when using HSS tools ground like yours. Your tools will cut more efficiently and can work at higher speeds. Accordingly, you can feed faster as well. Mess with this and learn how your tools like to cut. This his how we learn what our lathes want with the tools we use.


----------



## devils4ever

Per mikey's request on another thread, I'm posting my left and right hand HSS lathe tool bits here. Here's one that I think is properly formed.


----------



## devils4ever

This one I'm embarrassed to post. I know I messed up with the side angle is way too great, but I'm waiting until my belt grinder is done to fix. To fix on my bench grinder, will be tedious.


----------



## ttabbal

devils4ever said:


> Per mikey's request on another thread, I'm posting my left and right hand HSS lathe tool bits here. Here's one that I think is properly formed.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> View attachment 363113




Is this being held at an angle to the work? It looks like it might rub a little if straight on.

The cutting corner looks worn, or perhaps has material built up on it? Honing should be able clean that up. Try to keep them sharp. It makes a bigger difference than I expected. 

Consider trying the square tool. It works great for most work.


----------



## devils4ever

Yes, it is angled relative to the lathe axis.

I tried to put a radius on the cutting corner with a diamond hone. There may be some material built up on it as well. But, even after re-sharpening them on the grinder, they don't seem to cut any better.

Square tool? I'm not sure what you mean.


----------



## ttabbal

devils4ever said:


> Yes, it is angled relative to the lathe axis.
> 
> I tried to put a radius on the cutting corner with a diamond hone. There may be some material built up on it as well. But, even after re-sharpening them on the grinder, they don't seem to cut any better.
> 
> Square tool? I'm not sure what you mean.




One of the tools we discuss in the thread is called the square tool. There is some detailed information on how to grind one toward the beginning of the thread.


----------



## mikey

devils4ever said:


> Per mikey's request on another thread, I'm posting my left and right hand HSS lathe tool bits here.



Thanks for posting pics. Here is what I see:

The tool in post #1581 is a LH tool. It has decent relief angles, some side rake but no back rake. The nose radius is only on the very top of the tool and does not extend below that. The end cutting edge angle is very small so this tool will create a lot of deflection as the end edge contacts the work. This tool, as currently ground, will cut but it takes a big lathe to use a tool like this and it will be okayish for roughing but will not take very light cuts accurately.
The tool in post #1582 is a RH turning tool. It has what looks to be about 8 deg of relief, some side rake, no real back rake and the nose radius is only at the very top of the tool. The end cutting edge angle is large so it will access shoulders okay but this tool will not finish well except when taking very light cuts because there is no end edge to produce a finish.
For those of you who don't know what this is about, devils4ever stated that he can only take a max depth of cut of 0.010" on his 7X lathe and I asked him to post pics of his tool because his lathe should be capable of much better performance. As you can see, he has kindly done that. 

@devils4ever, after seeing your tools I can say that we can fix the LH tool but we'll tackle that later, after you learn to grind a RH tool. The RH tool you showed us cannot be fixed; there isn't enough material left. I suggest you grind a new tool and as @ttabbal suggested, I would grind a Square Tool. Detailed instructions on how to do that can be found here. Grind that new tool and then show us pics and we'll take it from there. 

The thread I linked to tells you how a turning tool is ground. It does not tell you why each tool angle is ground that way. The why is contained within this thread. Yes, it's a monster at this point but everything that I know about this subject has been poured into this thread. After you read through this thread I am totally willing to answer questions about HSS tool geometry you may have, although my answers qualify as just my opinion on the subject. 

Your lathe is capable of performing vastly better that you might think. Your tools are what is limiting you right now and luckily, that is easy to fix. Grind that Square tool and we'll take it from there.


----------



## Watchwatch

I’m beyond amazed. My 2x72 belt grinder build is finally complete and it was time for a quick test run before dinner. I slapped on a 36grit Norton ceramic belt and grabbed a junk 3/4 inch piece of Chinese HSS. Ground a 35 angle about .250 wide. It took maybe 15 seconds to grind and the bit was barely warm to the touch.


Sent from my iPhone using Tapatalk


----------



## ttabbal

Yup. A 2x72 with ceramic belts eats even HSS for breakfast. Cobalt makes it work a little bit... 

Congrats on the build! Always nice to see a tool you build work for the first time.


----------



## Z2V

Yep, welcome to the 2x72 club. I’ve lost count of how many belt grinders have been built as a result of this thread alone. I’m pretty sure mine is the most often used tool I have in my garage.
Thanks Mikey


----------



## devils4ever

I'm in the process of doing my 2X72 belt grinder build. I should have everything done in the next day or two except the tool rest. I'm working on the platen currently, but I can run a belt on it now. So, I might wait until this is completed before trying to create a square tool. The bench grinder is *so *slow.

I bought 36, 60, 100 grit ceramic belts for it along with 220 AO belts. I can't wait to try it on HSS. This is was the main reason for building it: HSS lathe tooling. I have a fine diamond hone. Do I need other grits? The square thread claims to need coarse, fine, and extra fine ones.


----------



## mikey

When you're done with your grinder, we will be here.

Having the three grits will greatly speed up your honing. HSS is hard and trying to remove coarse grinding marks with just a fine stone will take a very long time. Given the small cost for a pack of three stones, it is worth buying in my opinion. I get them every few years because I tend to wear them out but they are worth it.


----------



## Watchwatch

Based on my extensive 30 seconds of experience, I think you will be good to go. The finish I got with 36 grit was very nice. Invest in a bench stone and some diamond hones instead of additional belts.


Sent from my iPhone using Tapatalk


----------



## thomas s

Thank you Mikey. I don't think any other post got this many hits and it just keeps going.


----------



## 7milesup

Watchwatch said:


> I’m beyond amazed. My 2x72 belt grinder build is finally complete and it was time for a quick test run before dinner. I slapped on a 36grit Norton ceramic belt and grabbed a junk 3/4 inch piece of Chinese HSS. Ground a 35 angle about .250 wide. It took maybe 15 seconds to grind and the bit was barely warm to the touch.
> 
> 
> Sent from my iPhone using Tapatalk


Dangit..... now I have to build one of those....


----------



## ttabbal

7milesup said:


> Dangit..... now I have to build one of those....



You really do! I freaking love mine. It also does a great job putting a nice finish on parts with a finer belt.


----------



## mikey

thomas s said:


> Thank you Mikey. I don't think any other post got this many hits and it just keeps going.



Yeah, who woulda' thunk it? On the other hand, if confusion about how something worked had a degree of difficulty to it, HSS lathe tool geometry would have been #1 for me so I'm not surprised that it is for other guys, too. 

As I look back on this, isn't it amazing how many successes we've had? You and I have been grinding tools for well over 30 years so we know this stuff. Many of our newer guys have caught up or surpassed us with their very first try! Sorta' humbles you, right?


----------



## thomas s

sorta humbles you. Yes it does but because of your guidance I can grind a better tool now. And l thank you for that.


----------



## mikey

thomas s said:


> sorta humbles you. Yes it does but because of your guidance I can grind a better tool now. And l thank you for that.



That right there made all this effort worth it, Tom.


----------



## Watchwatch

Many many thanks Mikey. Followed your step by step and ground a general use knife and square tool. Both worked very well right off the bat on aluminum and 12l14.


Sent from my iPhone using Tapatalk


----------



## mikey

Watchwatch said:


> Followed your step by step and ground a general use knife and square tool. Both worked very well right off the bat on aluminum and 12l14.



You're welcome! Things should only get better from here as your skills grow.


----------



## Watchwatch

Finally hit a snag when I tried to grind a general purpose aluminum bit last night. 

Any tips for grinding the 40 degree back rake?

My table only extends half an inch behind the platen towards the motor. I know I need to fix that before I make another attempt.


Sent from my iPhone using Tapatalk


----------



## mikey

Clamp a piece of flat plate to your tool rest to give you support on the right side of the belt. Main thing is to be safe.


----------



## devils4ever

mikey said:


> When you're done with your grinder, we will be here.
> 
> Having the three grits will greatly speed up your honing. HSS is hard and trying to remove coarse grinding marks with just a fine stone will take a very long time. Given the small cost for a pack of three stones, it is worth buying in my opinion. I get them every few years because I tend to wear them out but they are worth it.



Well, I got my belt grinder done enough to use for this. I have 36, 60, and 100 grit ceramic belts and 220 grit (AO, I think) belts. 

I bought a set of Prolinemax 3/8" HSS lathe blanks, but I found a right hand bit that I bought previously (made in China) and tried to sharpen years ago. I also bought the credit card size set of diamond hones you recommended.

I tried the 60 grit belt on the left side of the bit with the table set to 15 degrees. I tried to figure out the other angle from your description. I think this can be computed by trig. You said to take about half of the end off and 1.5X to 2X down the length. So, that means arctan(0.5/1.5) = 18.4 degrees and arctan(0.5/2) = 14.0 degrees. So, I settled on 15 degrees to make it simple. Is this correct?  I still have to do the other 2 sides. 

Should I switch to the 100 or 220 grit belt before going to the diamond hones?

As far as the belt grinder goes, WOW! This things eats HSS. I was able to grind the side in a few minutes. On my bench grinder, this would have taken at least 45 - 60 minutes. Plus, the grind is straight and not concave.


----------



## mikey

devils4ever said:


> I tried the 60 grit belt on the left side of the bit with the table set to 15 degrees. I tried to figure out the other angle from your description. I think this can be computed by trig. You said to take about half of the end off and 1.5X to 2X down the length. So, that means arctan(0.5/1.5) = 18.4 degrees and arctan(0.5/2) = 14.0 degrees. So, I settled on 15 degrees to make it simple. Is this correct?  I still have to do the other 2 sides.
> 
> Should I switch to the 100 or 220 grit belt before going to the diamond hones?
> 
> As far as the belt grinder goes, WOW! This things eats HSS. I was able to grind the side in a few minutes. On my bench grinder, this would have taken at least 45 - 60 minutes. Plus, the grind is straight and not concave.



The side cutting edge angle is a non-critical angle. I just grind it so about half or a little more is ground off the end while also taking off about double the width of the bit. Let me explain.

The side cutting edge angle is also the lead angle of the tool when the tool is fixed perpendicular to the work piece. If it is fixed like this, that lead angle has a significant impact on cutting forces and radial forces in particular. The greater the lead angle, the greater the cutting forces are; the less the lead angle, the lower the forces are. HOWEVER, a QCTP allows us to position the tool quickly and alter this lead angle to whatever we want and, in fact, we do this all the time. This makes the side cutting edge angle far less critical and there is no need to be precise here.

As for grits, I grind with a 36 grit to shape and an 80 grit to take off the coarse grind marks before moving to a diamond stone. 100-120 grit belts will do it as well or better.

And yes, a belt sander is far more efficient at grinding HSS tool bits vs a bench grinder. This is especially true when we use ceramic belts. That is not to say that a bench grinder won't do a fine job of tool grinding; it is just not as efficient.


----------



## Watchwatch

36,100 hone has worked well for me


Sent from my iPhone using Tapatalk


----------



## mickri

Devils4ever I did all of the calcs to be able to use a combo square as a guide on my belt sander.  Look at my post #961 on page 97.  That might help you out.


----------



## devils4ever

Okay, I gave it a try. I must say that the 36 grit belt was eating the HSS too fast. I was removing material faster than I liked and switched to the 60 grit. This was followed by the 100 grit and then I tried honing them with the coarse and fine diamond cards. I put a small radius on the end using the coarse hone.

How's the geometry look?


----------



## mikey

Can't see the amount of back rake but from what I can see, you did a great job. The nose radius is well formed and consistent from top to bottom, which is what you want. The only suggestion I have is to hone each face better. Use your coarse card to get rid of the coarse grind marks. When each surface has a uniform scratch pattern from the coarse stone, step up to the fine stone and do the same thing. Finish up with the extra-fine stone and be sure to use that stone to freshen up the nose radius, then give it a few strokes on the top surface. A tool that is honed like this will slice paper and produce fine finishes while still being able to  rough as hard as your lathe can go.

Now see if you can beat 0.010"!


----------



## devils4ever

Here's a side shot showing the back rake.

Yeah, I'm having a hard time keeping the hones flat on the faces, but I'll keep trying. Do I need to use water or oil on the diamond cards like on traditional stones? 

Maybe, I'll try the 220 grit belt to help speed up the honing process.

Thanks so much, mikey!!!


----------



## mikey

The back rake is okay. Next one, try to maintain the 15 deg angle as you push the tool into the belt.

I use water on my diamond stones and flush it often. Don't use too much pressure; let the stone cut. Try honing on the pull stroke; it works better and you won't roll your edges. Focus on making each face flat and the edges will take care of themselves.


----------



## mickri

Mikey's the pro at this and gives really good advice.  Some of us like me have trouble honing.  I practice honing with varying results.  For example I can't sharpen a knife no matter how hard I try.  I now use a 300 grit belt instead of a hone.  It gives me a beautiful mirror like finish and no rounded edges.

Keep practicing at honing until you get it mastered.  In the interim use a fine grit belt.


----------



## brino

devils4ever said:


> I'm having a hard time keeping the hones flat on the faces



I have always found it easier to leave the flat diamond hone on the bench and hold the lathe tool bit.
First I rock the tool bit a little to ensure the face I'm honing is flat on the hone, then I grab it tight and try not to change my grip until I've done a half dozen or so swipes across the hone. Stop, rinse the hone and look to see if I should progress to the next grit hone.

It's the same as the directions to Carnegie hall.........practice, practice, practice.

-brino


----------



## devils4ever

mickri said:


> Mikey's the pro at this and gives really good advice.  Some of us like me have trouble honing.  I practice honing with varying results.  For example I can't sharpen a knife no matter how hard I try.  I now use a 300 grit belt instead of a hone.  It gives me a beautiful mirror like finish and no rounded edges.
> 
> Keep practicing at honing until you get it mastered.  In the interim use a fine grit belt.



So, you're saying a 300 grit belt is as good as honing?


----------



## devils4ever

mikey said:


> Now see if you can beat 0.010"!



Wow! I used a scrap piece of 3/4" 12L14 rod and was able to easily take off 0.030" and 0.040" when using a 0.004"/rev feed rate. At 0.050", it was bogging down and chattering until I changed the feed rate to 0.002"/rev.

I'm a believer!

On a 1-1/2" piece of 1144 "stressproof", I was only able to go to 0.020" per pass, but this might be because of the larger diameter. Or, it could be the tougher material.


----------



## mikey

Using a poorly honed tool vs a well honed one is the same as cutting with a dull vs a sharp knife; both will cut but the sharp one does it much better. Honing is a skill. Like all skills, it comes with understanding and practice. Try to remember that your goal is to remove grinding marks and make the face flat across the entire face. If you can do this for all three faces, their intersections will be dead sharp and will not reflect light. I'm no pro but I have honed hundreds of lathe tools and if I could pick one thing that makes a difference it would be your mindset: you are trying to make the flat ... flat. 



devils4ever said:


> Wow! I used a scrap piece of 3/4" 12L14 rod and was able to easily take off 0.030" and 0.040" when using a 0.004"/rev feed rate. At 0.050", it was bogging down and chattering until I changed the feed rate to 0.002"/rev.
> 
> I'm a believer!
> 
> On a 1-1/2" piece of 1144 "stressproof", I was only able to go to 0.020" per pass, but this might be because of the larger diameter. Or, it could be the tougher material.



Now that you accept that your tool can improve the performance of your lathe, you need to learn to use it. Start with the tool perpendicular to the work and find a depth of cut that causes your lathe to chatter, like that 0.050" deep cut you made in 12L14. Now rotate the tool to the left about 5-10 degrees and lock it down, then take that same cut and see what that does; I will bet the tool cuts without chatter. Mess with this tool angle thing (aka changing the lead angle of the tool) to see what your lathe wants to deliver max performance for you. 

Now that your tool can rough better, see if it can take a micro-cut. IF the tool is honed well, it should be able to take any micro-cut you can dial in. Try taking a half-thou cut and see if the OD really reduces by 0.001". Then take smaller and smaller cuts and see if the OD reduces as expected. My lathe tools will take a 0.0001" deep cut accurately. 

You will find that how big a cut a lathe can take matters little in a hobby shop. What matters is how small a cut it can take to bring you in on size. With a carbide insert, dialing in a micro-cut is difficult due to the impact of the nose radius. With HSS tools, things are much simpler and more direct. 

Once you determine how big and small your tool will cut, learn to use your edges to enhance finishes. I discussed this in the body of this thread; you might want to go look for it. 

Learning to use your lathe tools is important, whether you use carbide or HSS. Learn the strengths and weakness of both types and pull out the tool that the job requires. On a small lathe, most of the time, HSS will be a better choice but for some jobs you will need to use carbide. Learn how to choose an insert and how the nose radius dictates your cuts. Know how tool angle matters, even with carbide, so you can get the results you need. The only way to learn this is at the lathe; you cannot look it up on the net because the published info is for industrial lathes that most of you do not own. Once you know what your tools can do on your lathe, you are free to make a choice.


----------



## devils4ever

The side face is the easiest to hone. The top face is the hardest.


----------



## Z2V

I keep a small squirt bottle of water with a small amount of Dawn dish soap in it on my bench. The soap seems to keep the moisture on the diamond card while honing.


----------



## Brento

So i am in a predicament need a boring bar to bore a flat bottom 5/16 hole 1.5" deep any tips to make this boring bar out of 3/16 hss? I know it is going to take forever to grind.


----------



## fitterman1

Why not use a slotdrill?


----------



## Z2V

Why can you not use a 5/16” drill bit? You mentioned flat bottom, you can grind a drill bit to cut a flat bottom hole or even use a end mill.


----------



## Brento

I can only fit 1/4 shanks in my drill chuck in the tail stock. This is on my watchmakers lathe.


----------



## Brento

A slot drill could work but im wonding how much force that would be on steel in a tiny little lathe.


----------



## fitterman1

Most endmills dont center cut. Drill first undersize close to depth then go through with a slotdrill or flat bottom drill. Thats my method.


----------



## Brento

I was going to use an endmill but then when i got my chuck out i saw it was 1/4 max.


----------



## fitterman1

You can also turn down a 5/16 drill shank to fit your chuck


----------



## mikey

Brento said:


> So i am in a predicament need a boring bar to bore a flat bottom 5/16 hole 1.5" deep any tips to make this boring bar out of 3/16 hss? I know it is going to take forever to grind.



All good suggestions but I have to ask - what kind of accuracy do you need for this hole? Is it a precision bore or just a simple hole? The reason I ask is because if it is a precision hole then you need tiny boring bar, maybe 1/8" or slightly larger. A steel bar can go about 1/2" deep before deflection becomes an issue. A carbide bar can get you to 1" deep, maybe a bit more.

So, much depends on what the hole tolerances are.


----------



## Brento

Great question mikey. The bore is .312 +.005 -.000


----------



## Brento

I thought of reaming the hole but to get the flat bottom. There is a thru hole of .230 on the bottom of the part with a +.005-.000


----------



## Brento

For anyone wondering this is for a part in the dividing head group project.


----------



## Z2V

Could you use the tool post to hold a drill bit or end mill instead of the drill chuck in the tail stock?


----------



## mikey

With that kind of tolerances, you need to bore it. A drill or end mill will not net you that kind of precision. Given that there is a hole in the bottom of the bore, you will not need to get the point of the bar to get to center and you can get away with a larger bar without running it into the wall of the bore. I suggest a 3/16" diameter Micro 100 solid carbide bar that can cut to your 1.5" depth. It will take micro-cuts to allow you the kind of precision you require.


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## Brento

With it being such a tiny lathe it makes it hard to hold much bigger then a 1/4" shank.


----------



## Brento

mikey said:


> With that kind of tolerances, you need to bore it. A drill or end mill will not net you that kind of precision. Given that there is a hole in the bottom of the bore, you will not need to get the point of the bar to get to center and you can get away with a larger bar without running it into the wall of the bore. I suggest a 3/16" diameter Micro 100 solid carbide bar that can cut to your 1.5" depth. It will take micro-cuts to allow you the kind of precision you require.


So is carbide ok to use on little lathes like a watchmakers?  It would be considered to a sherline i believe or a unimat.


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## Brento

Do the micro 100 bars have flats on them?


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## ttabbal

Brento said:


> So is carbide ok to use on little lathes like a watchmakers?  It would be considered to a sherline i believe or a unimat.



No problem. Those micro 100 bars are crazy sharp and cut as well as a honed HSS tool. The ones to avoid are brazed carbide unless you have the gear to shape and hone them. Inserts generally come kind of dull too, but you can get polished versions. On a lathe that small, you are probably better off skipping those as well. @mikey has a Sherline, so he can speak from more experience. 

The micro 100 bars I have don't have flats. You can just set them up with the angle you need. I'm sure they have some guidance on the recommended angles, but I just start a few degrees off horizontal and adjust if needed.


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## mikey

Brento said:


> So is carbide ok to use on little lathes like a watchmakers?  It would be considered to a sherline i believe or a unimat.





Brento said:


> Do the micro 100 bars have flats on them?



Carbide bars are fine for even small lathes. They are very sharp and cut quite like a HSS bar.

Some Micro 100 bars do have flats on them. I use a bar holder that does not clamp the bar with screws so I can rotate and position the tool however I want so flats don't bother me. Your situation may differ.


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## fitterman1

+ 005 - 000 is a hell of a tolerance.
That means it can be 0.312 at its smallest diameter to 0.317 at its largest. A sharp drill will keep you within that tolerance easily.


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## Brento

Thanks mikey i trust you with working with a sherline. Ordered!


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## Brento

When anyone makes a radius tool. What do you guys do to try and hone them?  Just hit the top and call it a day?


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## mikey

Brento, are you referring to a form tool? If so, most have flat tops so you would hone the sides as best you can, then hone the top flat. How well the tools works depends on how well you can get the sides to meet the top.


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## Brento

Yes Mikey i am talking about a form tool. I just finished these tools up tonight. A 45 and a - threading tool that i modified to just be a chamfering tool.


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## mikey

Looks good! Just hone the sides and top and those will cut fine.


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## Brento

Already honed in the pictures. I have radius tools now to hone.


----------



## Janderso

I thought I had the perfect grind. What's wrong with it?
The correct answer is worth 5 points!!
Hint, it doesn't leave a very good finish on 12L14!


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## mikey

Janderso said:


> I thought I had the perfect grind. What's wrong with it?
> The correct answer is worth 5 points!!
> Hint, it doesn't leave a very good finish on 12L14!



Glad to see you taking a shot at this, Jeff!

You asked so I'm going to be honest and tell you what I think. Then we are going to fix it so that it works really well, okay?

It's really hard from me to tell but it looks like you might have decent relief angles under the edges. However, you have essentially no rake angles, which means you are trying to turn steel with a zero rake turning tool. It will work with brass but it will not turn steel well at all. To fix this, you need to grind some side and back rake into the top surface of the tool. 

Go to this thread and scroll down until you hit a subheading called "The Top". Have a look at how I set up the rake grinds and give that a try. Once you have the rake angles correct, stone a nose radius on the tool and try turning that 12L14 again. If you would, please post pics again so we can see your progress. Have a look at the way I took the pictures in that thread and duplicate them so we can see the angles you're grinding.

I also suggest you PM @Z2V and get ahold of the model tools he has. It will give you a better idea of what a turning tool looks like.

Stick with it, Jeff, and I will stick with you until we get it right.


----------



## Janderso

mikey said:


> some side and back rake into the top surface of the tool.


That's it!
I got all done with this, tried it out with poor results. I then noticed the top was flat!
Works great on brass with a slow feed.
I'll post after I regrind. Try it out.....


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## Janderso

Much better. The radius and side rake helped a bunch. The tool is sharp!


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## mikey

Better, Jeff. I can see some side and back rake now. The nose radius is too large and your edges are NOT sharp. If you look at the shot with the top view, you can see light reflecting off the cutting edge. That means the top is not flat all the way to the cutting edge. In 12L14, a good tool will produce almost a mirror finish. I would hone all three faces to get then dead flat and then the tool will cut as it should.


----------



## Janderso

mikey said:


> Better, Jeff. I can see some side and back rake now. The nose radius is too large and your edges are NOT sharp. If you look at the shot with the top view, you can see light reflecting off the cutting edge. That means the top is not flat all the way to the cutting edge. In 12L14, a good tool will produce almost a mirror finish. I would hone all three faces to get then dead flat and then the tool will cut as it should.


Easier said than done pal.
I’m really struggling keeping the stone from wandering and screwing up my edge.
I have several stones to choose from.
I’m going to try my new lapping machine
thank you for your help!
Grinding HSS is easy, just like golf


----------



## Aukai

It's muscle memory, tricky at first, when your fingers start learning how to respond to what your eyes are seeing it will be much better. I'm using diamond lapping plates, and getting more comfortable with it.


----------



## mikey

Aukai is right - it takes time to build hand-eye coordination. 

I think the grinder you're using is one reason why you're having difficulty. Do you have a belt sander or bench grinder available to you? If so, they will work much faster and better to create the flat faces you need. 

I've tried to convey to folks that we are trying to grind flat faces on our tools. The reason for creating those flats is so that when we get them really flat then its simple to then hone them so that the edges where those flats intersect are razor sharp. 

None of this is really difficult (says the guy who has ground hundreds of tools and can do it in his sleep as a result) but it does take some time to learn to do it quickly and well. Stick with it, Jeff. There will come a time when a HSS tool is the right tool for the job and you'll have it when you need it.


----------



## devils4ever

My belt grinder makes roughing the surfaces really quick and easy. However, I'm having issues honing them also. Can I use 600 and 1200 grit belts instead? This would help tremendously!


----------



## mikey

Absolutely.


----------



## Janderso

Well, I just spent an hour regrinding another piece of quality HSS. I didn't make any progress. About the same.
I got the angles wrong.
Back to the drawing board.
Maybe I should find out how to do it first. I hate directions!


----------



## Janderso

devils4ever said:


> My belt grinder makes roughing the surfaces really quick and easy. However, I'm having issues honing them also. Can I use 600 and 1200 grit belts instead? This would help tremendously!


I forgot about my belt grinder!
That will save time.


----------



## devils4ever

Janderso said:


> I forgot about my belt grinder!
> That will save time.



Yes. I'm still finishing up my 2X72 belt grinder build, but this thing *eats *HSS like it's wood!

I can't believe I waited this long to build one. Another plus is it grinds flat faces not concave surfaces. This makes it easier to measure angles.


----------



## Janderso

I started over, used the belt grinder, 600 grit diamond plate, 1,000 then 1,500.
Made a cut, same results. It cuts the Finish is smooth to the touch but it’s not the mirror I get with carbide.
These pics are after I made a .020” cut. .008” per rev at 460 rpm.
Change the speed? Feed rate?
I go faster with carbide.
The pic where the tool tip looks dull is after a one inch cut.
This is old school, Rex HSS.
I’m done for a while. I have to walk away.


----------



## Janderso

devils4ever said:


> My belt grinder makes roughing the surfaces really quick and easy. However, I'm having issues honing them also. Can I use 600 and 1200 grit belts instead? This would help tremendously!


Have you seen the scotch brite belts?
I haven’t used mine yet but if they‘re anything like the wheels!!


----------



## mikey

Janderso said:


> I started over, used the belt grinder, 600 grit diamond plate, 1,000 then 1,500.
> Made a cut, same results. It cuts the Finish is smooth to the touch but it’s not the mirror I get with carbide.
> These pics are after I made a .020” cut. .008” per rev at 460 rpm.
> Change the speed? Feed rate?
> I go faster with carbide.
> The pic where the tool tip looks dull is after a one inch cut.
> This is old school, Rex HSS.
> I’m done for a while. I have to walk away.



Jeff, your tool has good relief angles and decent side rake but zero back rake. See how the edge is horizontal in pic 5 above?

Have you ever seen the model tools we have been sending out? If not, PM @Z2V and have him send you a set so you can see what the tools look like. Take a break until you get them, maybe?

A properly ground HSS tool will more than keep up with a carbide tool. In fact, my tools will take a deeper roughing cut than my carbide tools will and will easily take a micro-cut that no insert will take. Try dialing in a 0.0001" deep cut with an insert and see what happens to your accuracy. 

I know it isn't easy to grind tools in the beginning but it gets better, much better, if you stay the course and learn the skill.


----------



## Watchwatch

devils4ever said:


> My belt grinder makes roughing the surfaces really quick and easy. However, I'm having issues honing them also. Can I use 600 and 1200 grit belts instead? This would help tremendously!



Here is my noob experience with the finer belts on my 2x72. 

They suck with the softer HSS steels. The joint will quickly create a facet. Finish with a 120g ceramic belt at full speed and use a bench stone for honing with normal HSS.

I ground a Rex95 bit last week and had good luck using a finer belts. I noticed the finish was bad with the ceramic belts. I stepped up to a 220 grit belt, hit the bit on a bench stone to shine it up, checked for facets, and repeated the process as I stepped up grits.


Sent from my iPhone using Tapatalk


----------



## WobblyHand

@Janderso page 10, post #104 gives you the directions you need.  @mikey's write up is amazing.  He has great pictures, and clear instructions.  This thread has greatly increased in size since that time, so you may have missed it.  As stated very early in this thread, practice with cheap keystock.  I know it helped me a lot to get the basic shapes right.  Wish the honing was easier for me, but, I'm still working on that.  Need to build a nice low speed grinder like yours!


----------



## Janderso

mikey said:


> Jeff, your tool has good relief angles and decent side rake but zero back rake. See how the edge is horizontal in pic 5 above?
> 
> Have you ever seen the model tools we have been sending out? If not, PM @Z2V and have him send you a set so you can see what the tools look like. Take a break until you get them, maybe?
> 
> A properly ground HSS tool will more than keep up with a carbide tool. In fact, my tools will take a deeper roughing cut than my carbide tools will and will easily take a micro-cut that no insert will take. Try dialing in a 0.0001" deep cut with an insert and see what happens to your accuracy.
> 
> I know it isn't easy to grind tools in the beginning but it gets better, much better, if you stay the course and learn the skill.


Yeah I noticed that. The strange thing is I started out with a side rake. I must have allowed it to go neutral.


----------



## Janderso

I spent the morning going through this thread. I then added some back rake to my new attempt.
Same ****ty results.
After spending 4-5 hours on this subject, I think it’s time to try try again some other time.
I understand the basics, I think I have a fair cutting tool but the results are not adequate.
It’s probably not sharp/honed properly.


----------



## WobblyHand

@Janderso you are getting the basic shape much better, so that's an improvement.  To help further, you need a better focus on your first two pictures.  When they are blown up they are out of focus.  A trick I use for phone cameras is to put something very close to the part you want to focus on, like a piece of paper.  This fools phone camera autofocus and makes the edges and faces in focus.  The third picture is in focus and I can see on the back edge (and front edge) a black ridge of metal extending above the top face.  This means they are not honed right.  You need to hone the top as well.  There should be no crud visible on these edges.

I find getting this right hard.  It certainly tests my patience.  But when it is right, the tool cuts very well.  It's very worthwhile to keep on plugging at it.


----------



## mikey

It can be frustrating grinding and not getting the results you want. This is why I highly recommend you start learning to grind tools using mild steel keystock until you have the process down. It takes a bit of practice learning how to move your hands and keystock is cheaper and easier to grind than HSS. 

Jeff, please buy some keystock at the hardware store in your desired size. Cut it into tool bit size chunks. Read this article and try to duplicate the steps shown until you can grind the desired angles into the tool. Switch to HSS when you can grind keystock accurately. 

If I can, then you can.


----------



## Janderso

mikey said:


> It can be frustrating grinding and not getting the results you want. This is why I highly recommend you start learning to grind tools using mild steel keystock until you have the process down. It takes a bit of practice learning how to move your hands and keystock is cheaper and easier to grind than HSS.
> 
> Jeff, please buy some keystock at the hardware store in your desired size. Cut it into tool bit size chunks. Read this article and try to duplicate the steps shown until you can grind the desired angles into the tool. Switch to HSS when you can grind keystock accurately.
> 
> If I can, then you can.


Thank you for your time and attention.
I stock, key stock.
I have a full range of McMaster key stock.
That is a great idea!
Learning the process this way makes sense.


----------



## mikey

Janderso said:


> Thank you for your time and attention.
> I stock, key stock.
> I have a full range of McMaster key stock.
> That is a great idea!
> Learning the process this way makes sense.



Brother, I said I will stay with you until you get it. I meant that.


----------



## devils4ever

I bought some finer belts for my grinder (320, 600, and 1200) to use in place of the diamond hones since I was having trouble keeping the hones flat on the faces. Here's the results. It's hard to tell from the pics, but the surfaces appear fairly well polished. What do you think?


----------



## mikey

Looks pretty good to me. Can't tell how the intersections are but as long as they don't reflect light then it should work. I think I would still at least put a light hone on each face, though. Proof is in the pudding; if it cuts well then it's good enough!


----------



## devils4ever

I did my best to hone the faces. I think they look pretty good.

I was able to take 0.040" deep cuts in 3/4" 12L14 steel without issue. I didn't try any deeper. Here's the results. What do you think? This was a 0.010" deep pass at 675 RPM with 0.004" feed rate.


----------



## Brento

Yesterday i finished my last internal radius tool. Have to get a picture when im back home but now to try and hone it. I am not sure how i am going to do it.


----------



## Brento

Picture as promised


----------



## Watchwatch

Advice for grinding a finishing fly cutter bit? I’m looking to flatten aluminum fixture plates.

A vertical shear bit looks promising. 


Sent from my iPhone using Tapatalk


----------



## ttabbal

Watchwatch said:


> Advice for grinding a finishing fly cutter bit? I’m looking to flatten aluminum fixture plates.
> 
> A vertical shear bit looks promising.
> 
> 
> Sent from my iPhone using Tapatalk



I use a left hand square tool for most fly cutting. It works great.


----------



## Z2V

Like @ttabbal , I also use a left hand turning tool.


----------



## Watchwatch

How did you grind the square tool? Mikeys general use square bit which is 15 degree all around?


Sent from my iPhone using Tapatalk


----------



## ttabbal

Watchwatch said:


> How did you grind the square tool? Mikeys general use square bit which is 15 degree all around?
> 
> 
> Sent from my iPhone using Tapatalk



Yes. Nothing real special, and it works great.


----------



## devils4ever

For a 60 degree threading tool, I assume I would just keep the 15 degree clearance angles and leave a flat top?


----------



## ttabbal

devils4ever said:


> For a 60 degree threading tool, I assume I would just keep the 15 degree clearance angles and leave a flat top?



Yes. I mark the 60 degree point where I want it on the tool, then keeping the table at 15 degrees, grind the point. So I get the clearance angle needed, but it keeps the top flat and the grind is simple.


----------



## devils4ever

I have to give a major kudos to *mikey*. Thanks to his instruction and guidance, I'm getting better and better at getting my HSS lathe tools ground correctly. I can take much bigger DOC now on my lathe and I get long spiral chips coming off the tool which I never did before. I'm sure they are not perfect, but they are a major improvement of what I was getting previously.

With my newly completed belt grinder, I can fix my previous attempts quickly. It's easy to regrind the tool with a coarse belt something that my bench grinder would have takes 10X -20X longer. I'm using very fine belts now (600, 1200 grit) to give the HSS a nice polish. I still use the diamond hones to touch up things, but I have to admit, I'm not that good with them. Holding the hones flat on the faces can be tricky especially the front and top faces.

One thing I noted is that using the 600 and 1200 grit belts overheats the HSS much quicker than the coarse and medium belts. This seems counterintuitive. When using these belts, a light touch is required with frequent dipping in water.

In any case, a big thanks to mikey!


----------



## Aukai

Your hands, and fingers are getting used to the orientation needed, which makes your confidence go up too. I am still not 100% comfortable with the lapping plates, and the flatness needed for a good hone. Good job.


----------



## ttabbal

It's funny. I'm actually MORE likely to grind facets into the tools with the belt grinder than the diamond plates. Just goes to show that everyone is different.  Nice to see more people being successful grinding tools. It's a very useful skill even if you use a lot of inserts.


----------



## WobblyHand

Yesterday I ground a LH knife tool.  It's not pretty by any means.  I had a lot of trouble putting in the top face due to the limitations of my belt grinder.  I really find it hard to do the honing.  First it's the patience to go through all the grits.  Definitely getting better at that.  Fine grit will not remove gouges, only the coarser (coarsest) will do that.  So get it flat with the coarsest grit possible!  If that is done, going through the grits is easy.  Don't use a lot of pressure, let the grit do the work.  Just work on the mechanical movement of your hand to make it as robotically smooth as possible.  That helps immensely.  If you can only take 1 inch strokes but they are flat, you will eventually get there.  

The tool did the job that I needed it to do.  I had to remove 0.004" from the bottom of the head of a shoulder washer.  There's a lot of freedom when one can grind one's one lathe tools..





Bushing (shoulder washer) is under the leftmost screw.  I had to remove 0.004" from the bottom side of the flange, which made the distance between the plates 0.004" wider.  This prevents the center arm from binding on the outer plates.


----------



## tmenyc

I was reading through this tome again a week or so ago, and came across a comment of Mikey's that he would make a roughing square with fewer compromises than an all purpose square tool, with 15 deg SRA, 12 deg ERA, 24 deg side rake and 15 deg back rake. So I tried one... actually forgot to change the table from 15 to 12 for the end cut so both are 15. That 24 degree side rake was a bear to grind, and it's cobalt!
But it cut really well. The final picture shows a .020 cut @780 rpm and .004 feed, the thicker portion on the left, polished a little with emery. I need to make the nose radius a bit more even. Also, it's not flat since I'm using a 6" bench grinder, not a belt.










Thanks for looking!
Tim


----------



## WobblyHand

About a week ago, I finally finished a square tool in cobalt steel.  I must be doing something wrong as the tool lasted maybe 5-10 minutes before the tip breaking.  I had made a flat on the edge and attempted to radius it.  This isn't the first time I've "accomplished" this.  It's getting frustrating putting in so much work honing only to have the tip break off.  All 4 of my square tools, be they HSS or cobalt have done this.  Clearly something isn't right.

So, perhaps only for my review, how should the tool be used?  Wrong angle with respect to the workpiece?  Asking myself if it's tool abuse, junk metal, or bad grinds or what?  My carbide tips TCGT don't last as long as I'd like either.  They are delicate and I tend to chip them, even when it's not an interrupted cut.  I store the tools in their OXA holders in red plastic Schaller bins.  I'm not purposely jostling them together.  If there's two in a bin I face them so the dovetails overlap and the points are far from each other.  

I'll get pictures when I get back to the shop.


----------



## ttabbal

What are you cutting and what are your feeds and speeds?

0XA makes me think mini lathe. Is that the case?


----------



## WobblyHand

ttabbal said:


> What are you cutting and what are your feeds and speeds?
> 
> 0XA makes me think mini lathe. Is that the case?


Mostly easy stuff, 12L14, 6061.  I have done O-1, but not much.  It's all manual right now, slow feeds.  No tach, but relatively low speeds based on the rheostat.  But maybe the SFM is off.  I need to be more careful about that.  You guessed right.  Mini-lathe. 

If I set it up to feed, it's too fast, due to how the mini-lathes are geared.  So I get a better finish with a manual feed.  (Backwards, right?) One day I'll make a bigger gear to reduce the feed rate.  The breakages have been primarily on steel.


----------



## ttabbal

Odd that the feed is so far off. I would think they would include a gear that could get you down to 0.005"/rev or less. That's what I usually do for roughing. 

Nothing against mini lathes, beats no lathe.  just helps to have an idea of ridigity available. What depth are you trying to cut? 

No tach... You should consider adding one or even just a standalone tach gun. They are inexpensive and help a lot. If you are wearing carbide tips quickly, it makes me think that you are running faster than you might expect. And if the speed is enough to wear carbide, it's likely to burn HSS pretty quickly. For now, if your machine has belts to adjust speed ranges, make sure you are in low range. Then turn it down and use a smallish diameter workpiece. Perhaps 1" or less aluminum. Just to get a feel for what's happening. Take a pass and look at the finish, chips, and heat levels of the material and the tool. Those can tell you a lot about the forces on the tool. On steel, do you have the chips changing color? 

Can you post a pic of the tool angles you have?


----------



## WobblyHand

Max RPM is 2300 on my mini-lathe.  I don't run it that fast cutting!  Mini-lathe just isn't rigid enough for that.  The speed is electronically controlled, there are no belt positions to shift.  I'm usually running near 650 RPM, but that all depends on lots of stuff, like diameter, and if there's chatter.  If there's chatter then I back off.  Got to confess, I tend to forget running the SFM calculation, but it's rare that I'm machining poor machining steel.   There's allegedly a tach output connector on the lathe, but the display was wildly overpriced a year ago.  Maybe I can make an Arduino read out the pulses and display it for a lot less.

DOC's are very modest only 0.010 to 0.015.  I let the lathe tell me what it can do, so I don't push it beyond what it can do.  This makes lathework kind of slow, but, that's what one gets with that entry price point.  Gibs are adjusted to be relatively tight to minimize lifting and to maximize rigidity for the platform.

I seem not to be wearing carbide, it's more chipping.  It could be a function of the quality of the inserts and the type.  But this thread is about grinding tooling, so let's focus on that.  More specifically the square tool.  I haven't had an issue with my knife tools, left or right hand.  Maybe that's because I only use them to shave off a thousandth or two.  I have yet to crack the tip on the knife.

What do you mean by tool angles?  The grinds themselves or the angle of the tool when on the lathe?

Here is a square tool that is in process, it's not completely finished.  It's in HSS.  I have not put a flat on the edge, nor radiused the edge.  Honing is not complete, especially the small flat in the third picture..  The shape is representative of my other square tools.  I will bring up the chipped cobalt one and photograph it as well.  In my mind, thought the cobalt one came out better, but the photos will be the judge of that.


----------



## devils4ever

If your mini-lathe is similar to mine, the feed rate is 1/256 of the spindle speed. That is about 0.004"/rev. This is calculated as (20/80) * (20/80) * (1/16) = 1/256. The 20/80 reduction is from the gear train and the 1/16 is from the lead screw pitch. Beware that this is for my Micro-Mark Tru-Inch mini-lathe, yours might be slightly different. But, you can do the same calculation.

I converted to Clough42's ELS system. Now, I can dial in 0.001"/rev up to 0.040"/rev. The ELS gives you RPMs as well. You might want to consider doing this conversion as you can change the feed rate as you are turning. This makes it easy to turn to a shoulder by slowing the feed rate as the cut nears the end. Also, you get metric threading for free!

I'm still learning to grind my HSS lathe bits. I found the belt grinder orders of magnitude easier than a bench grinder. It's vastly faster and cooler and you get flat faces. My turning improved a lot by getting and keeping the faces polished by honing. It's makes a big difference. I can take take 0.040" DOC in steel now. Before I was taking between 0.005" and 0.010" DOC.


----------



## WobblyHand

devils4ever said:


> If your mini-lathe is similar to mine, the feed rate is 1/256 of the spindle speed. That is about 0.004"/rev. This is calculated as (20/80) * (20/80) * (1/16) = 1/256. The 20/80 reduction is from the gear train and the 1/16 is from the lead screw pitch. Beware that this is for my Micro-Mark Tru-Inch mini-lathe, yours might be slightly different. But, you can do the same calculation.
> 
> I converted to Clough42's ELS system. Now, I can dial in 0.001"/rev up to 0.040"/rev. The ELS gives you RPMs as well. You might want to consider doing this conversion as you can change the feed rate as you are turning. This makes it easy to turn to a shoulder by slowing the feed rate as the cut nears the end. Also, you get metric threading for free!
> 
> I'm still learning to grind my HSS lathe bits. I found the belt grinder orders of magnitude easier than a bench grinder. It's vastly faster and cooler and you get flat faces. My turning improved a lot by getting and keeping the faces polished by honing. It's makes a big difference. I can take take 0.040" DOC in steel now. Before I was taking between 0.005" and 0.010" DOC.


I'm in awe of your work.  You have done some pretty cool stuff.  It would be awesome to convert to ELS.  My mini-lathe has the same identical gearing and lead screw.

Agree that using a belt grinder is lots easier.  My belt grinder is sub par, so I'll end up making one of my own.  It's on the "projects I'd like to do this year" list.  I have limited access on one side of the belt which makes it hard.  So for my new grinder I need to make a table that is omni-directional.   

I'd love to be able to do 0.040 DOC in steel, but I'm not there yet.


----------



## ttabbal

OK... so let's assume 650 RPM. With a 1/2" work piece, that's 85 SFM. That should be in the range of what a HSS tool can handle in mild steel easy enough. Let's stick to known material for now, once you start getting into unknownium, you could be dealing with Iconnel for all we know.  Say 12L14 for steel and 6061 aluminum. 

Your tool pics look pretty good, so the basic angles look alright. Don't go too nuts with the tip radius. 1/64" or so is plenty. If you don't have a radius gauge to compare against, go for "barely not pointy".  Then try to get the edges honed as well as possible. 

I've found that the things I kill edges with are RPM vs hardness, chatter, and crashing. I'm going to assume you didn't crash, so chatter. Can you try a 0.01" DOC with everything but the carriage locked? The compound can be a big contributor here. Maybe just start with aluminum and see how the tool and part feel. If we're close, it shouldn't have heated much. Double check the tool tip height as well, being off center can cause issues as well.


----------



## WobblyHand

No inconel!  A bit too exotic for me and my wallet.  Haven't done any unknownium either.  Didn't crash. 

My mini-lathe doesn't have a way to lock the slide, or the compound.  Don't know of any mini-lathe with that ability.   I could "add" locking to mine, but in general, these mini-lathes are not maxi-featured.  The gibs could be further tightened, although they are on the stiff side already.  Good point on the tooltip height, I will make sure of that.  I'll give it a try tonight.


----------



## ttabbal

Ah, I have not used one, I didn't realize it didn't have locks. I guess you could tighten the gib, but then you would lose your adjustment. Not ideal.


----------



## soniamann

It was very useful for me, thank you.


----------



## ttabbal

So, my first go at trepaning didn't work so well, lots of chatter. I ground it mostly like a parting tool, but with a bit more relief on the outside to avoid rubbing, which does seem to be good. I suspect it's just a bit wide for my lathe, at about 0.2". Material is 6061 aluminum, but will be cast iron eventually. But I have seen small lathes run larger form tools, so I'm scratching my head a bit.


----------



## Downunder Bob

ttabbal said:


> So, my first go at trepaning didn't work so well, lots of chatter. I ground it mostly like a parting tool, but with a bit more relief on the outside to avoid rubbing, which does seem to be good. I suspect it's just a bit wide for my lathe, at about 0.2". Material is 6061 aluminum, but will be cast iron eventually. But I have seen small lathes run larger form tools, so I'm scratching my head a bit.


You don't say what machine you are using and what is the trepanning dia., what is the material thickness etc. a pic might help. I suspect 0.2 might be  little wide for the tool. How much overhang do you have on the tool?


----------



## ttabbal

Downunder Bob said:


> You don't say what machine you are using and what is the trepanning dia., what is the material thickness etc. a pic might help. I suspect 0.2 might be  little wide for the tool. How much overhang do you have on the tool?



It's a PM1127. About 2" diameter, I'm going for a groove about 0.316" wide and deep. Tool has about 1" overhang, 3/8" M2 HSS. I measured the angles after thinking about it and I suspect I need to add some more clearance angle on the sides. Other suggestions are welcome.


----------



## WobblyHand

About a year ago, I made a trepanning tool.  Just measured it at 0.130" wide.  I had to have the cross-section be a triangle in order to get enough clearance.  The bottom off the tool is sharp, not because it is a cutting edge, but because I needed to get the relief.  Used mine to make a spindle light out of 6061.  Used it to cut out the center, as well as to make slots.  Diameter of slot was on the order of two inches, like your application.

I only have a mini-lathe, and it cut fairly well.  Used about a 3/4" overhang from the tip.  3/8" M2.  Try reducing overhang and add more relief.  The front of the tool should define the cut.  There should be slight relief towards the base/back of the tool.  Length of cutting tip is about 0.425"


Still use the tool to make grooves and widening slots.


----------



## ttabbal

I'll get a pic later, it might be helpful to others. I ended up a little rounded on the outside edge, a sharper angle would have worked just as well though. I think my sides are more straight than I was aiming for, so I'm going to start there, I do have some rake on the top, so I think it's good there, but I'll go over it again with fresh eyes. I'm close, and get a decent chip, I just want to get the chatter under control. It's an interesting operation I've never tried before.


----------



## WobblyHand

I would think a rounded edge might not give enough relief on the outside edge, but truly, I'm just a beginner at this.  I defer to others with far more experience.  The tool was good enough for what I needed to do.  Could it be made better?  Very likely.  First time trepanning was unsettling, to say the least.  Once the edges were sharp and had sufficient relief, had no troubles.


----------



## ttabbal

I'm still getting a little chatter, but it's much improved. I didn't hone it much for this test, so I'll do that as well. 

I went back and watched a video from Joe Pieczynski's channel and got a good tip that helped a fair bit, keep pressure on the handwheel. It chatters more with lighter pressure, keeping the tool tip buried in the work helped. I'm sure pulling it back into the holder helped as well. 

The biggest change in the grind was to taper from the front cutting edge. I had intended that, but didn't get enough. I also ground a steeper angle on the outside. 

Thanks for the suggestions!


----------



## Jimsehr

ttabbal said:


> View attachment 379107
> View attachment 379108
> View attachment 379109
> 
> 
> I'm still getting a little chatter, but it's much improved. I didn't hone it much for this test, so I'll do that as well.
> 
> I went back and watched a video from Joe Pieczynski's channel and got a good tip that helped a fair bit, keep pressure on the handwheel. It chatters more with lighter pressure, keeping the tool tip buried in the work helped. I'm sure pulling it back into the holder helped as well.
> 
> The biggest change in the grind was to taper from the front cutting edge. I had intended that, but didn't get enough. I also ground a steeper angle on the outside.
> 
> Thanks for the suggestions!


----------



## brino

ttabbal said:


> I'm still getting a little chatter
> ........
> Thanks for the suggestions!



@ttabbal 

Are you sure it's not rubbing here:



I would try to give that area a little more clearance.

-brino


----------



## Brento

I have a question. I finally am able to start cutting on my 9A and im going to make a Generic tool for cutting and turning in one. Is that possible. Is it possible to make the tool without having to rotate the toolpost?


----------



## ttabbal

Brento said:


> I have a question. I finally am able to start cutting on my 9A and im going to make a Generic tool for cutting and turning in one. Is that possible. Is it possible to make the tool without having to rotate the toolpost?



Are you using a QCTP or the older style lantern toolpost? The tools we make here are designed for the QCTP where you hold them mostly flat with the ways. The basic ideas will work, but the angles will have to be adapted. 

Why hesitate to rotate the tool? I do it all the time. 

Turning is cutting, so I'm missing something.  I use the square tool most of my general turning. If you mean facing cuts, I use a square there too, just in a different holder so it hangs out the other end and put it on the other side of the post. The knife tool works pretty well there too.


----------



## Brento

QCTP but i like leaving the block square to the work so i would like to make a generic square facing/turning tool in one. But id also like to use it to turn up to a corner and face out.


----------



## ttabbal

Brento said:


> QCTP but i like leaving the block square to the work so i would like to make a generic square facing/turning tool in one. But id also like to use it to turn up to a corner and face out.



You will want to try to mimic the angles on a carbide insert holder, having the cutting point to the left and forward by a few degrees to get clearance for both. Perhaps angle the bit in the holder a few degrees left so you can clear everything without grinding the whole length of the bit. It's easy enough to set the block straight when I want it that way, so I've never tried it myself, but I think it would work. I just use a faced off part or the tailstock quill to make it square. Quick and more than square enough for my needs. If you are setting it with a tenths indicator, that might take a bit longer.


----------



## Brento

So this is a stupid rough sketch i just did on my phone but would i have an my cutting trouble on my 9A if i made my square tool like the little sketch on the right?  I know the square tool is generally made like on the left but i find it harder to turn up to a shoulder then. I am trying to make the tool so i do not have to rotate my qctp block and i can keep it nice and straight. If it will cause problems cutting then i will make it the normal way.


----------



## woodchucker

I don't think so. I have cutters that I ground similar, it cuts fine.
and if you don't like it, well re-grind it.


----------



## Jimsehr

Should work fine.


----------



## fitterman1

If you want to angle that face in you can, all your doing  is grinding away a lot more material than with the conventional tool.
I would like to see more of a radius on the cutting tip though as this strengthens the cutting edge and it will last longer. Also, the smaller you go on radius the greater the chance of stress cracks developing if there is a significant amount of load on the part.
The tools you grind will be for a specific profile you wish to turn on your work, apart from the basic tools of turning, parting etc.
As long as you have the requisite clearances and rakes you can't go wrong.
Get cracking.


----------



## Tim9

I think your tooling needs a completely STRAIGHT TOP edge on the side clearances. I see some rounding.  Its a very tricky grinding of the tooling. Its hard for me to put this in words.  That inside grind not only needs clearances on the leading edge but  needs  a little clearance from leading edge and a little towards the QCTP. So not a straight and flat grind but give it a little relief so its fatter at the tip and the thinner leading to the QCTP.  Thats in addition to the 5 degree normal relief we always hear about. I would want the 5 degree side relief plus a little relief so the tip is also fatter than the body heading inwards. I'm absolutely no expert. But I tried a little trepanning a while back and if the tool grind is the slightest bit off.... I had a rubbing issue. I would suggest grind it and then paint it with some magic marker. try it....then hone it with a diamond hone to get it so only the top of the front of the tooling is touching. Pay attention for any rubbing of the side of  too...not just at the front tip. You want contact ONLY at the top and front tip cutting edge.


----------



## Brento

Today i ground my facing/turning tool at work and then tonight i honed the radius and the edges.  She feels pretty sharp. I will use this for finishing most likely. But we will see. I may still have to twist my tool post block to make it work on bigger diameters but we will see.


----------



## Jimsehr

ttabbal said:


> View attachment 379107
> View attachment 379108
> View attachment 379109
> 
> 
> I'm still getting a little chatter, but it's much improved. I didn't hone it much for this test, so I'll do that as well.
> 
> I went back and watched a video from Joe Pieczynski's channel and got a good tip that helped a fair bit, keep pressure on the handwheel. It chatters more with lighter pressure, keeping the tool tip buried in the work helped. I'm sure pulling it back into the holder helped as well.
> 
> The biggest change in the grind was to taper from the front cutting edge. I had intended that, but didn't get enough. I also ground a steeper angle on the outside.
> 
> Thanks for the suggestions!


I ran production runs of trepanned parts out of tool steel and ground all the tools by hand. Hundreds of them Each run.


			The Trouble With Trepanning! -  		 		The Home Shop Machinist & Machinist's Workshop Magazine's BBS


----------



## ttabbal

Jimsehr said:


> I ran production runs of trepanned parts out of tool steel and ground all the tools by hand. Hundreds of them Each run.
> 
> 
> The Trouble With Trepanning! -  		 		The Home Shop Machinist & Machinist's Workshop Magazine's BBS




Thanks for the idea! I'll try running upside down from the back next time.


----------



## fcs

The narrow tool that Clickspring uses in his latest video 



for turning to a shoulder at both ends; does it have a name? I could use something like that instead of different tools for each end.


----------



## mikey

Round nose tool.


----------



## Tim9

Check this out. Joe goes into depths with the explanation of everything one needs to pay attention to.


----------



## Aukai

I decided to try to shape a GP tool with a 5/8 Wesson Tantung "G" blank. I'm trying 12* for now since it is a hard but brittle material, my CBN wheel, and belt grinder got a workout, then I got a work out on the diamond lapping plates. I was not getting good results taking pictures so this is what I got,


----------



## mikey

Good job! That tool will cut.


----------



## riversidedan

try making an oversize tool out of wood to check its shape and profile......


----------



## Aukai

I hope it will, I went back to your HSS thread, and some research on the bit it's self, I took a WAG on how to shape it, and wow, that's some hard stuff. I'm not sure my 80 grit CBN wheel is still 80 grit, and I need to change my ceramic belt too.


----------



## woodchucker

I have the same stuff. If I remember correctly, you don't cool the tool, if you do it can breakdown from the shock.
Look it up to be sure.


----------



## benmychree

What do you intend to use it for, material wise? I may not be the best choice of tool bit.


----------



## woodchucker

From Wesson's website:  see attached pdf from their catalog about grinding this is a snippet.


----------



## Aukai

Thanks WC I did see that, good information.
I am changing a bell housing that was intended for a twin sintered iron disc, and floater, back to a std depth can, and will have to shorten the input shaft. The company said I should try to cut it myself, they do it all the time  I'm worried about the splines being an interrupted cut though. I do have 431, and 432 CNMG bits to try also.


----------



## Aukai

I went as deep as .080 DOC in 1.250 4130 bar stock @ 300 rpm, the feed rate might be off, I did not have time to play with it. I did notice that ~1/4 to 3/8" off of the bar it stayed a straw color, and then turned a dark blue, this was with no mist coolant.


----------



## woodchucker

for those of you that can't grind HSS worth a damn.
I recommend these 4 videos from Mr. Pete. They will help you grind if you insist you can't


----------



## Tim9

I actually watched his video last night. It’s a very good instructional video.
   The grinding jig/holder is slick. It would surely be easier than free hand. That said, if you take your time and refer back to the pictures in the South Bend instruction book ( how to use a lathe) ,  it’s really not hard to grind your tooling fee hand. Like Mr Pete says multiple times….  There’s a lot of leeway in the angles. You don’t need any special tools to grind a useable hss cutting tool.


----------



## WobblyHand

woodchucker said:


> for those of you that can't grind HSS worth a damn.
> I recommend these 4 videos from Mr. Pete. They will help you grind if you insist you can't


I can grind them ok.  Where I fall apart is in honing them.  I end up ruining the edges more often than not.  I need to make a couple of honing guides.  Just can't hold the small faces consistently flat to the honing surfaces.  The largest face is easy, it's the smaller ones that I have trouble with.  Keep on rocking them and wrecking the edge.  Kind of like Sisyphus, almost there and the rock goes tumbling back down the hill 

I will watch these videos.  Hope to find something that works.

What do you do for small HSS tools, the kind you need to inspect or grind under a microscope?  I need to make a grooving tool with a 0.05" radius.  Hogging out the material is not that hard, but how to do the fine work in a reasonable amount of time?  Seems like one needs a fixture, but I'm having trouble even imagining one.  Can you point me in the right direction?


----------



## mickri

I have several different belts for my belt sander.  I mostly use an 80 grit to start with.  Depending how rough the grind is with the 80 I will sometimes touch it up with a 300 grit.  If I want really polished faces I finish off with a leather strop belt.  To get the compound angles I tilt the table for one angle and use a combo square for the other angle.  That way the tool bit is always flat on the table.  No rounding of the edges.


----------



## mikey

I don't grind tools that often but I hone them all the time. *You screw up honing when you get in a rush*. One bad pass on a diamond stone will take multiple good passes to fix so make each pass count. 

Each of us has physical differences. Some of us can hold an angle better on the push stroke and some can pull more steadily; you need to find out which way is best for you and hone that way. Some folks need the stone flat on a bench, some need to have it in their hand; figure out what works for you. Sort out your specific needs and then practice. Honing actually takes time to learn. It is harder to hone well than to grind well. Take your time, make each stroke count.


----------



## WobblyHand

mikey said:


> I don't grind tools that often but I hone them all the time. *You screw up honing when you get in a rush*. One bad pass on a diamond stone will take multiple good passes to fix so make each pass count.
> 
> Each of us has physical differences. Some of us can hold an angle better on the push stroke and some can pull more steadily; you need to find out which way is best for you and hone that way. Some folks need the stone flat on a bench, some need to have it in their hand; figure out what works for you. Sort out your specific needs and then practice. Honing actually takes time to learn. It is harder to hone well than to grind well. Take your time, make each stroke count.


If I were to hone any slower it would be 2122 before I finished.  It's pretty apparent this is a learned skill that requires tactile feedback.  It's very frustrating because I am not getting it.  I know it is possible, but don't know exactly what to do, what grits to use and when to change, and _how it feels when it is being done right_.  So I guess, and guess and seem to be getting it wrong every time.  Since I cannot feel when it is going right, there's no feedback to me.  I can tell if something went bad - it feels a little different, but at that point, I've lost 4 or more hours of work.  This is one of the most frustrating things for me.

I may make a fixture to help me maintain honing position, especially for the small faces.  Perhaps then I can learn how one can guide the piece and feel the correct cutting/honing action by sheer repetition.  Later I may not need the fixture, or maybe I will.  I'm avoiding HSS for the most part because I'm ruining the edges and spending weeks on it and getting nowhere.  I'd like to learn this skill, but have to say, so far this has been eluding me.


----------



## mickri

There's got to be someone close to you who could watch you and give you some tips to get you up to speed on honing.

If you are pulling towards you there can be a tendency to lift the back end of the tool bit towards the end of the stroke.  This will round the edge slightly.  Also are you honing up and down or front to back.  I don't know if that makes sense.  The first picture is front to back.  The second picture is up and down.  Very easy to round the cutting edge honing up and down.  Just the opposite for front to back





Sorry for the poor quality of the pictures.  Just some quickies to show the orientation of the hone to the tool bit.


----------



## mikey

It might help to know that the goal of honing a lathe tool is to simply make each of the three faces flat. As for grits, I suggest using three grades of diamond stones - coarse, fine, extra-fine. You are simply trying to create a homogeneous finish for each stone you use. For example, when going from a freshly ground face you use the coarse stone to remove the grinding marks and produce a consistent scratch pattern from the coarse stone. Once you get that consistent pattern across each of the three faces, move to the fine stone and do the same thing, then repeat with the extra-fine. 

If you can do this while keeping each face dead flat then the intersections between those faces will be razor sharp. Other than putting a nose radius on the tool, that's about all there is to honing. Not sure how to make it easier than that.


----------



## WobblyHand

mikey said:


> while keeping each face dead flat


This is the problem.  I am having difficulty doing this.  

I understand conceptually what needs to be done, but my execution is flawed.  

I've tried drawing towards me, pushing away and probably a few other things.  It's ok for a while then acckk, I lift or roll the edge.  My hand sort of cramps, it doesn't feel like a cramp, but my hand changes position or something.  The smaller the face, the harder it is for me to keep the face flat to the hone.  Basically my hand can't tell if the tool face is truly flat to the surface.  I can feel if I have ruined the edge, but can't tell that I'm about to ruin it.  Been a tough way to learn this skill, since I can't sense when it is ok, or when I am slightly off.  Definitely an exercise in frustration.

On the other hand I have no issue with grinding the faces on a belt sander, I generally get that part fine.  This is because the tool is on the rest, and I can control 2D with my hand ok if the tool is flat on the table.  It's the 3D, or more accurately the dual angle in space that I haven't got the hang of.


----------



## mickri

I put my index finger on top of the side opposite the face I am honing.  Fairly easy to feel when the hone is flat on the face.  The index finger also applies the pressure to keep the face flat on the hone.

Is your hone fixed to the work bench?  Easier to feel if the face is flat against the hone if the hone is fixed in position.  That way you can use both hands to guide the tool bit.  Another tip.  Don't move the tool bit back and forth on the hone.  Take a stroke in one direction.  Pick the tool bit up and return to your starting point.  Then take another stroke.  It should only take a couple of long steady strokes to clean up the face.


----------



## woodchucker

WobblyHand said:


> I can grind them ok.  Where I fall apart is in honing them.  I end up ruining the edges more often than not.  I need to make a couple of honing guides.  Just can't hold the small faces consistently flat to the honing surfaces.  The largest face is easy, it's the smaller ones that I have trouble with.  Keep on rocking them and wrecking the edge.  Kind of like Sisyphus, almost there and the rock goes tumbling back down the hill
> 
> I will watch these videos.  Hope to find something that works.
> 
> What do you do for small HSS tools, the kind you need to inspect or grind under a microscope?  I need to make a grooving tool with a 0.05" radius.  Hogging out the material is not that hard, but how to do the fine work in a reasonable amount of time?  Seems like one needs a fixture, but I'm having trouble even imagining one.  Can you point me in the right direction?


I was honing a tool the other day for cutting threads, and it was so sharp I cut myself on my thumb while holding one of the other edges down... I guess it was sharp enough... 
I don't fully agree with the left and right turning tools many times. I use them opposite so I can get close to interferences.. I use my left turning for threading next to a shoulder for instance.


----------



## WobblyHand

mickri said:


> I put my index finger on top of the side opposite the face I am honing.  Fairly easy to feel when the hone is flat on the face.  The index finger also applies the pressure to keep the face flat on the hone.
> 
> Is your hone fixed to the work bench?  Easier to feel if the face is flat against the hone if the hone is fixed in position.  That way you can use both hands to guide the tool bit.  Another tip.  Don't move the tool bit back and forth on the hone.  Take a stroke in one direction.  Pick the tool bit up and return to your starting point.  Then take another stroke.  It should only take a couple of long steady strokes to clean up the face.


I do something similar.  I can easily tell when the hone is flat on the face when on the big face, but for the top face and the front face, it isn't that easy for me to feel it.

Hone is on a flat machined 3/8" thick aluminum plate.  It isn't fixed to the bench, but just sits on it.  I just move the tool in one direction, pick it up and return to start.  I think I'm basically doing what you have written.

I think I'm not grinding enough with a fine grit on the belt sander.  That's forcing me to get a workout honing to get rid of the grooves.  I'll try a finer belt for the finishing before moving on to honing.  That might be the root issue.


----------



## mickri

What grit are you using on the belt sander?  A light touch on the belt sander also helps keep the grooves to a minimum.


----------



## WobblyHand

mickri said:


> What grit are you using on the belt sander?  A light touch on the belt sander also helps keep the grooves to a minimum.


It's been awhile, don't remember.  I'll be trying to grind a tool tomorrow.  I have a 60 & 80 grit ceramic belt, and I think a 100 grit alumina.  Have a couple more belts, but don't remember what they are.  I don't think I have anything fine like 300...

Edit: When I bought my ceramic belts they didn't offer fine grits higher than 100.  Now they do offer them up to 400.  The alumina belts I have are not very good.  Like the ceramic grits a lot better.


----------



## Ken226

I didn't read through all 175 pages, but has anyone tried solid modeling something in CAD that can be 3d printed?   Just as a physical example that could be used as a guide.

It might be easier for someone just starting out to download and print a set with the correct geometry,  than trying to grind out an example the first time from keystock or wood.


----------



## mickri

My main belt is an 80 grit ceramic.  I also have a coarser belt for hogging off metal on a new grind.  It might 36 grit.  Once I have the basic shape I then switch to the 80 grit.  And if I want a finer finish I then go to the 300 grit.  Rarely use the leather strop.

Ken226 I haven't heard of anybody 3d printing a tool bit.  Mikey would know that.  Lots of people have made models out of wood or key stock.  There was even a set of models made out of key stock that were making the rounds.  Don't know whatever happened to those.


----------



## WobblyHand

Ken226 said:


> I didn't read through all 175 pages, but has anyone tried solid modeling something in CAD that can be 3d printed?   Just as a physical example that could be used as a guide.


I think there have been a couple of folks that have done this, or at least tried.  

I was playing around with this today, and confusing myself with 3d geometry.  I'll figure it out, but this afternoon was temporarily confused about doing the datum plane rotations and translations.  Found the tools a lot easier to grind in real life than modeling them in 3d!


----------



## Ken226

I'll work on one too see how it goes, and post the results.


----------



## Jim F

Ken226 said:


> I didn't read through all 175 pages, but has anyone tried solid modeling something in CAD that can be 3d printed?   Just as a physical example that could be used as a guide.
> 
> It might be easier for someone just starting out to download and print a set with the correct geometry,  than trying to grind out an example the first time from keystock or wood.


There are examples ground on key stock floating around.
just request an example be sent to you.


----------



## Ken226

Jim F said:


> There are examples ground on key stock floating around.
> just request an example be sent to you.



I've had my own for a long time.  Just thought I'd try the challenge of modeling one in CAD.


----------



## Jim F

Ken226 said:


> I've had my own for a long time.  Just thought I'd try the challenge of modeling one in CAD.


Not everyone has a 3D printer.....
Or can use a CAD program......


----------



## Ken226

Jim F said:


> Not everyone has a 3D printer.....
> Or can use a CAD program......



No, not everyone.  For those that do and find it helpful, maybe its worth the effort.  Maybe not.  But, it only costs a few minutes and a small amount of internet bandwidth.  

There are many services online these days that let you upload a cad file, will 3d print models and mail them to a customer for a modest fee.  Also, many who don't have a 3d printer may have friends who do and can simply download a file and have a friend print it for them.

For those that don't, or don't find it helpful, or have no interest, this post may not be for them.  I won't force anyone to read any of my posts .






There is a downloadable .stl file of the above model attached to this post.  Inch dimensions, so for most slicer programs you'll have to convert it to metric.


----------



## mickri

I made 3d models in Sketchup and previously posted them in this thread.  Back on page 80. post #799


----------



## mikey

WobblyHand said:


> Hone is on a flat machined 3/8" thick aluminum plate.  It isn't fixed to the bench, but just sits on it.  I just move the tool in one direction, pick it up and return to start.  I think I'm basically doing what you have written.
> 
> I think I'm not grinding enough with a fine grit on the belt sander.  That's forcing me to get a workout honing to get rid of the grooves.  I'll try a finer belt for the finishing before moving on to honing.  That might be the root issue.


You might want to try putting the stone in your non-dominant hand and hold the tool in your dominant hand. Get the face of the tool flat on the stone and feel it register, then push or pull and make a single pass and then repeat. It might work better than laying the stone on the bench. I hone my tools as above.


----------



## Z2V

I’ll put the tool in side a piece of 3/8” automotive hose to make it easier on the old hands. I’ll usually grind with the finest  ceramic belt then hit it with a 300 grit AO belt.


----------



## WobblyHand

Z2V said:


> I’ll put the tool in side a piece of 3/8” automotive hose to make it easier on the old hands. I’ll usually grind with the finest  ceramic belt then hit it with a 300 grit AO belt.
> View attachment 405105


That's really a good idea.  I find my fingers go numb grasping the steel non-sharpened edges.  I will try this.  I'll see if I can get finer belts as well.  Think I'm spending far too much time on hand honing, since I'm not grinding with fine belts.  Definitely worth a try!


----------



## WobblyHand

mikey said:


> You might want to try putting the stone in your non-dominant hand and hold the tool in your dominant hand. Get the face of the tool flat on the stone and feel it register, then push or pull and make a single pass and then repeat. It might work better than laying the stone on the bench. I hone my tools as above.


I will give this a try.  What approximate stone size are you using?  My bench stones are 75 x 170 mm, but I do have some smaller ones which might be easier to hold.  I think I have 3 stones about playing card size that might work.  

Looks like I should get some finer belts as well.  Been wasting a lot of time just removing grinding marks rather than minor honing the surface.


----------



## devils4ever

I was having the same trouble you guys are having with honing. The belt grinder was pretty straightforward in getting the geometry right,  but the honing was giving me issues.

I now use the belt grinder for honing. I use 600 and 1200 grit belts and the surface is like a mirror and much easier than using the diamond honing cards.


----------



## ttabbal

devils4ever said:


> I was having the same trouble you guys are having with honing. The belt grinder was pretty straightforward in getting the geometry right,  but the honing was giving me issues.
> 
> I now use the belt grinder for honing. I use 600 and 1200 grit belts and the surface is like a mirror and much easier than using the diamond honing cards.




As long as you can accurately align the faces with the belt, it's a good method. But even a slight misalignment will grind all sorts of interesting facets on the tools. Nothing wrong with the method, it can just go sideways fast. Just mentioning it in case new guys have an issue so they have an idea of what to look at.


----------



## devils4ever

ttabbal said:


> As long as you can accurately align the faces with the belt, it's a good method. But even a slight misalignment will grind all sorts of interesting facets on the tools. Nothing wrong with the method, it can just go sideways fast. Just mentioning it in case new guys have an issue so they have an idea of what to look at.



You are correct. After swapping belts, you must make sure the angles are the same as before. I use a digital level that's accurate to 0.1 degree to reset my table after changing belts. This seems to be good enough and works for me.


----------



## mikey

WobblyHand said:


> I will give this a try.  What approximate stone size are you using?  My bench stones are 75 x 170 mm, but I do have some smaller ones which might be easier to hold.  I think I have 3 stones about playing card size that might work.
> 
> Looks like I should get some finer belts as well.  Been wasting a lot of time just removing grinding marks rather than minor honing the surface.


I mostly use the credit card size for honing. In my hands, it takes only a few strokes per face. Just keep in mind that I've honed thousands of tool bits so this might not be the average experience. 

Honing is a skill and like any skill, it takes time to acquire. It's like learning to file accurately ... not that easy to do at first but it comes with time.


----------



## WobblyHand

mikey said:


> I mostly use the credit card size for honing. In my hands, it takes only a few strokes per face. Just keep in mind that I've honed thousands of tool bits so this might not be the average experience.
> 
> Honing is a skill and like any skill, it takes time to acquire. It's like learning to file accurately ... not that easy to do at first but it comes with time.


Couldn't find my CC sized hones, but found some Eze-Lap's.  This honing skill seems to be eluding me.  

Ground an o-ring tool on my belt sander with 60 grit and 120 grit ceramic belts.  That's as fine as I have.  Then used my carbide grinder with a CBN wheel to do the rounding and finish to size.  The CBN wheel gives a relatively fine finish.  Honing went pretty slow but ok.  Things go south when I have to change hands.  I stroke from the "I don't care side" to the "I care about this edge" side.  I still manage to slightly ruin the cutting edge.    I can maintain one hand in position, but not two at the same time, it appears.  I need some kind of fixture to help, as this feels like madness, doing it over and over again and expecting a different (good) result.   

Hope I saved this tool bit enough to do what I want to do, which is to cut a simple rounded o-ring groove.  Total DOC of the groove will be 0.050, which is the radius of the tool.  




Me honing the tool seems to make the piece worse rather than making it better.  Fortunately this is for 6061 aluminum.  I'll try a test cut and see how it does.


----------



## mickri

Order some fine belts and be done with honing.  Not worth your aggravation.


----------



## WobblyHand

mickri said:


> Order some fine belts and be done with honing.  Not worth your aggravation.


Doesn't seem to be a skill that I have at the moment.  Not for a lack of trying.  But need to move on.

Red Label Abrasives has a fine ceramic grit belt assortment that I will get.  [P180, P240, P320 & P400]  Should be fine for what I do.

For what it is worth, the tool bit cut ok with some expected chatter on my 6061 test piece on my mini-lathe.  I hand turned the chuck for the last 0.010" depth at 0.001" depth steps and the finish came out chatter-free enough.  I can still see it, but I believe the o-ring should seal on that.  The surface where the 124 o-ring is now, is much better than the one on the right.  Looks like I should have cut deeper, if I look at the o-ring.  (Maybe even wider as well.)  

The real workpiece is on my G0752Z, waiting for this bit.  The valve design doesn't look like this and has more support for the o-ring on the left side.  Just playing around a bit so that I can learn on a non-critical piece.


----------



## fitterman1

Oring grooves should have a flat bottom with radii in the corners, so the material can be compressed slightly and has space to move in.
Whats wrong with a 2mm parting blade for grooving?


----------



## WobblyHand

fitterman1 said:


> Oring grooves should have a flat bottom with radii in the corners, so the material can be compressed slightly and has space to move in.
> Whats wrong with a 2mm parting blade for grooving?


Not disagreeing with you at all. 

The o-ring is not seated against a right cylindrical wall surrounding the piston.  The piston and o-ring seal against a tapered conical surface. Sort of like this picture.  I have no idea why the valve is designed this way, but I merely want to copy the piston warts and all.  The valve is designed to prevent outside contaminated water from entering the indoor potable water system.  Rather copy it than become creative, for this one part.


Kind of a quick and dirty addition of the conical seat for the o-ring.


----------



## fitterman1

Is it a static seal that the top bit sits on top of?


----------



## fitterman1

Thr reason I ask is because it takes a reasonable amount of effort to compress an oring to create a seal thats watertight.
If something is just seated atop an oring there is no guarantee of a seal occurring.


----------



## WobblyHand

fitterman1 said:


> Thr reason I ask is because it takes a reasonable amount of effort to compress an oring to create a seal thats watertight.
> If something is just seated atop an oring there is no guarantee of a seal occurring.


The piston is forced upwards by the water pressure, about 45 pounds/square inch to seal the o-ring.  This is part of a commercial and approved backflow prevention valve, pretty sure it has been engineered correctly.  There is about a 5 pound spring (wild guess) that pops the valve open if indoor water pressure is lost.  This is supposed to prevent irrigation water from re-entering the potable water system.  Which is why I am copying it, rather than changing it.

Here is a rough rendering of the spring pushing down the piston face.  Think it is tapered this way.


----------



## fitterman1

Gotcha, in other words it is a one way check valve in hydraulic terms.


----------



## WobblyHand

fitterman1 said:


> Gotcha, in other words it is a one way check valve in hydraulic terms.


Exactly!


----------



## mickri

Going to be machining some bearings out of delrin for a friend.  The bearing are around 2.375 OD and 1.911 ID.  1.25" long.  I will be rechecking all of my measurements this weekend.  The bearings are for a rudder shaft on a Santa Cruz 27 sailboat.  I have never worked with delrin before.

I will be starting with 2.5 OD  4" long rod held in a 3 jaw chuck.  Plan to turn the OD first and then bore the ID.  I could do it the other way too.  ID first then OD.  Makes no difference to me.  I would like to bore all the way through.  That way I can test fit the bearing on the shaft without removing the bearings from the chuck

Looking for suggestions on clearance and rake angles and speeds and feeds.


----------



## DavidR8

Never turned Delrin before but I have turned some nylon. Super sharp tool just like Mikey shows worked a treat.


----------



## fitterman1

Plus one for the super sharp tool.
Positive rake is a must from my experience.
Your clearance will be determined by shaft diameter and how much the delrin swells once submerged in water.
If i remember right, nylon swells quite a bit. Vesconite is good for potable water, it has a very low absorption rate. Couldn't tell you how it performs in saltwater.
A thou per inch of diameter is the general rule of clearance. Adjust it for swell and you can't go wrong.
Set your feed to your speed to achieve the smoothest finish.


----------



## ddickey

Usually you'd want to finish the ID then finish the OD as the OD can move when the ID is done. This is in general not Delrin specific.


----------



## mcdanlj

mickri said:


> Going to be machining some bearings out of delrin for a friend.  The bearing are around 2.375 OD and 1.911 ID.  1.25" long.  I will be rechecking all of my measurements this weekend.  The bearings are for a rudder shaft on a Santa Cruz 27 sailboat.  I have never worked with delrin before.
> 
> I will be starting with 2.5 OD  4" long rod held in a 3 jaw chuck.  Plan to turn the OD first and then bore the ID.  I could do it the other way too.  ID first then OD.  Makes no difference to me.  I would like to bore all the way through.  That way I can test fit the bearing on the shaft without removing the bearings from the chuck
> 
> Looking for suggestions on clearance and rake angles and speeds and feeds.



I haven't done precision work in delrin, so my limited experience that it's been forgiving of rake angle may not be highly applicable. I've used a sharp flat turning tool (for brass) and polished aluminum inserts both; even with a sharp, high rake edge it didn't seem to grab and pull, but it also turned nicely with the flat tool. Given that it will swell in water, precision probably is not super relevant for you either, but you'll need clearance. What's the diameter of the rudder shaft?

Might want to ask your friend about instead using UHMWPE (swells in hydrocarbons but not water) or Vesconite (especially if the sailboat has a reserve engine and might have gas/diesel/oil near the stern) instead. @fitterman1 wasn't sure about saltwater, but it's OK: https://www.vesconite.com/marine/


----------



## mickri

This sailboat is over 40 years old.  The Santa Cruz 27 was the first pocket rocket downwind flyer.  The marketing slogan was "Fast is Fun."  The original ULDB.  Light weight, no engine and minimal accommodation down below.  It was the fastest 27' sailboat for decades.

 I measured the rudder shaft at 1.911"  I am going to measure it again this weekend because 1.911" is not close any standard size stainless steel round bar.   And the shaft has not been machined.  I think that my measurement is off by .025 which would make the shaft close to 1 15/16."  The shaft is polished smooth where the bearings rode against the shaft.  You want absolutely no play in the rudder.   I plan to machine the ID to a tight slip fit.  Same for the OD.

We looked into UHMWPE.  The consensus was that it is difficult to machine to close tolerances because of thermal expansion.  My friend wants delrin.  That is what has been recommended to him by shipyards that have replaced these bearings. 

Thanks for the suggestion to do the ID first.


----------



## mickri

My friend measured the rudder shaft this afternoon and came up with the same basic numbers that I did.  He measured the shaft at 1.910."


----------



## fitterman1

Is that the diameter of the unworn shaft or the worn part where the bushes run?


----------



## mickri

1.911" is the diameter of the unworn shaft.  I measured the shaft at the bottom bearing at 1.911 fore and aft and 1.906 athwartships.  The shaft at the top bearing had uneven wear.  From memory the shaft at the top bearing was 1.905/1.903 or maybe 1.901.  The unworn shaft has to fit through the bottom bearing.  The rudder is inserted into the boat from the bottom.  The top bearing can be made to fit where it goes on the shaft.  I will have the rudder so I can test fit the top bearing on the top of the shaft.  Part it off and then fit the bottom bearing to the unworn shaft.


----------



## fitterman1

Some pictures would help.
Is the shaft removable from the rudder?
 If so, you can replace it with a larger one and clean up the old bushes to suit.
Can you skim the whole shaft and then make new bushes?
It sounds like the top shaft journal can be machined down to clean up and a new bush made easily.
I'm trying to come to grips with the bottom journal, as long as you can make a new bush and slide it down to its journal with minimal interference and the correct clearance you should be fine.
You state it is 6-8 thou undersize in the middle of the journal but ok at each end which I find odd.
In this situation I would expect the journal to wear eccentrically so the wear is greater on one side. but I could be wrong.


----------



## mickri

The old bearing were destroyed in removing them.  Had to cut them apart.  The rudder shaft is not removable from the rudder.  There is no way to machine the shaft.

You have misunderstood my nomenclature.  Fore and aft is boat talk for front to back or bow to stern.  Athwartships is side to side.  I don't know how else to explain it.  The wear is eccentric.  There is more wear side to side then front to back.


----------



## fitterman1

Starting to make sense now . Seems like all wear takes place on the sides of the shaft journals as the load is concentrated on those points depending on which way you are steering to turn.
Over time as wear increases the cross section of the journal becomes oval shaped.
Therefore if the rudder is pointing at 180 degrees to direction of travel most of your wear will show up at 90 and 270 degrees which will measure less than at 0 and 180 degrees.
I can't see an easy solution to fitting new bushes unless you machine the shaft journals round again as the rudder and shaft will destroy the new bushes in a short time.
I think your friend is up for a new rudder assembly.


----------



## Brento

Any tips on hss grinds for cutting hardened steel bushings about 3/16 in diameter?


----------



## Aukai

I think the start is to find the correct grade of HSS, and to make your DOC deep enough to get under the depth of hardening. Let's see what the gurus say....


----------



## fitterman1

I think you will find they are through hardened at that size


----------



## Cavediver

So, are there still a few of the sample sets floating around?  After a couple of months of stalking Facebook Marketplace, I finally scored one of the coveted(?) 1/2hp Craftsman Belt Sanders.  I'm working up my material list for the rest and will order materials on Monday.  I'm guessing it'll be a month or so before I have the modifications done due to a scheduled vacation, but would love to get busy sharpening as soon as it's complete.  

I've also recently purchased a Logan / Wards 10" lathe.  It needs a good cleaning and a new belt, but should be good to go around the same time.  I'm looking forward to this as I've been using a cheap HF 7x10 with lots of issues...

Attached is the general and very rough plan for the new rest, taken straight from that excellent article by @mikey .


----------



## DavidR8

Calling @Z2V! @Cavediver is looking for a set of HSS tool models...


----------



## Brento

Ive gotten to where i know this hss will cut the bushing. It is a matter of geometry. I havent cut to many things on the Lathe that are hardened

Edit: i am trying to cut this on my little watchmaker’s lathe. I can just go to the south bend instead. Do you think the brazed carbide bits would work good or stick with an insert. It would also help to have a small nose radius.


----------



## Brento

Should i grind a tool as if i am cutting tool steel? This is where i need the Guru help. I have hss cobalt blanks.


----------



## ddickey

.


----------



## ttabbal

Brento said:


> Should i grind a tool as if i am cutting tool steel? This is where i need the Guru help. I have hss cobalt blanks.



That's about where I would start with it. A good cobalt should hold up to it, though you will have to watch SFPM. Trying to go too fast will damage the cutter. It's pretty hard to go too slow with HSS. Make sure it's honed well. It really helps. 

Inserts should work as well, you will need to get a deeper cut going for most of them though. They can also handle higher speeds, and usually work better with the speed cranked up. 

Brazed carbide, you need to shape and hone with diamond tools. As delivered, they always seem to be improperly set up. At least for hobby guys with smaller machines etc.. They might be great on large industrial machines, I wouldn't know.


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## Brento

I believe i am on the slowest rpm on the watchmaker’s i didnt want to go to fast. I could bump it up i guess. I have diamond sticks to hone the brazed carbide. I found a decent looking one that i could use with a little honing. For how small the part is i could maybe go one belt notch faster. After that i will just go to the big lathe and go with carbide.


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## Brento

What type of radius would be ok is the next question. I need a radius but it has to be small to get into the corner of the little part well.


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## ttabbal

I saw your other thread, I didn't realize how small the part is. Yeah, you can probably speed it up some. 

I would keep the radius small, but it might help make it easier to get the radius in the shoulder if you use something close to the radius you want in the part. Increasing the radius also increases the tool pressure, but you do get a better finish unless you cause chatter. If you do have chatter, you might want to remove most of the material with a very sharp tool with minimal radius, then switch to a larger radius tool to make a finish pass. Unless you're getting into form tool territory, I doubt it will be much of a problem though.


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## Brento

Yea ill try speeding it up with the new tool and see what i get.


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## Brento

Fresh ground in 5 minutes. Need to put a little radius on it and hone it. Hopefully that will take care of my problem. If not, off to the southbend.


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## Brento

The little Derbyshire just couldnt do it. Tried a few speeds and it just kept rubbing before cutting. I didnt want to waste more time and put more work on the little lathe so off to the Southbend.


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## Z2V

Cavediver said:


> So, are there still a few of the sample sets floating around?  After a couple of months of stalking Facebook Marketplace, I finally scored one of the coveted(?) 1/2hp Craftsman Belt Sanders.  I'm working up my material list for the rest and will order materials on Monday.  I'm guessing it'll be a month or so before I have the modifications done due to a scheduled vacation, but would love to get busy sharpening as soon as it's complete.
> 
> I've also recently purchased a Logan / Wards 10" lathe.  It needs a good cleaning and a new belt, but should be good to go around the same time.  I'm looking forward to this as I've been using a cheap HF 7x10 with lots of issues...
> 
> Attached is the general and very rough plan for the new rest, taken straight from that excellent article by @mikey .


Yeah, there are probably 20 or more sets floating around out there. Honestly, finding a set to be forwarded to you would involve much more effort than just making a set and dropping them in the mail to you. I’d have to sort through pages of PM’s to figure out who has a set to forward you.
‘Drop me a PM with contact info and I’ll make a set in the next day or so and get them to you.
‘Remember, these will be made of cheap key stock. NOT WORKING TOOLS, they  are just models for you to work to. 
‘Glade to do it, just get me your contact info

Jeff


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## Just for fun

Would you be into making two sets?  Or maybe @Cavediver would send them to me when he gets a handle on grinding his own. 

Tim


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## Jim F

I have a set I can forward.
PM me the shipping info.


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## OCJohn

I’d like to host a set for a little while, too, when one becomes available.


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## Just for fun

Sounds like there is some renewed interest in the HSS samples.

@Jim F , I just sent you a PM


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## Aukai

Hopefully the people who have sets will see this, and offer to send theirs out. If they need to they can copy them to new key stock to save as reference.


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## ttabbal

If we need them, I can make some up.


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## Z2V

Thanks Travis for the offer but I think we have it covered.


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## matthewsx

I'm ready for a set, have lots of HSS that needs grinding....


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## Z2V

matthewsx said:


> I'm ready for a set, have lots of HSS that needs grinding....


PM me your contact info and I‘ll get a set to you.


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## brino

It's good to see this great thread (and sample sharing) still going strong!
Brian


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## tweinke

Almost the 5 year birthday of this thread! It certainly contains a wealth of knowledge that has helped people learn to grind HSS. A huge thanks to Mikey for getting this started!


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## Karl A

I have compiled a table of Mikey's lathe tools in this thread. Here it is. Additions and corrections are welcome.



Note on the knife tool: Mikey states in the post https://www.hobby-machinist.com/threads/models-for-grinding-hss-lathe-tools.62111/post-514166 "... that due to the conservative rake angles, pointed tip and small nose radius (~1/64”), this tool does not turn well on longer work. It tends to inscribe a spiral pattern in the work surface so don’t use it for general turning unless you enlarge the nose radius."

Additions to the table on 15-Sep-2022: brass tool, round nose tool, and information source: thread post #. To determine the page number that a post is on, divide the post # by 10, and round up. Examples: Post #102 is on page 11; post #420 is on page 42; post #1355 is on page 136.


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## Karl A

After having and using a 55-degree carbide-insert tool and an HSS RH knife tool for two years, I realized only this week that the tools are basically carbide and HSS versions of the same tool. The 55 degrees of the carbide insert is the same thing as the 35 degree end-cutting-edge angle of the HSS tool. One difference between them is that the carbide-insert tool has a few degrees of negative side-cutting-edge angle.


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## riversidedan

Karl A said:


> After having and using a 55-degree carbide-insert tool and an HSS RH knife tool for two years, I realized only this week that the tools are basically carbide and HSS versions of the same tool. The 55 degrees of the carbide insert is the same thing as the 35 degree end-cutting-edge angle of the HSS tool. One difference between them is that the carbide-insert tool has a few degrees of negative side-cutting-edge angle.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> View attachment 420318


Been using a boring bar like the carbide tool on the left for facing tool but would like to grind HSS tool like the one on the right so a 4 view pic would be helpful    so I can get the shape right


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## Karl A

riversidedan said:


> Been using a boring bar like the carbide tool on the left for facing tool but would like to grind HSS tool like the one on the right so a 4 view pic would be helpful    so I can get the shape right


For a description and grinding directions (with photos) of the right hand knife tool, see Mikey's post here
https://www.hobby-machinist.com/threads/models-for-grinding-hss-lathe-tools.62111/post-514166
and Mikey's subsequent post.


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## Karl A

I edited the table of Mikey's lathe tools in my post on the previous page.

I added the brass tool and the round nose tool.
I added the information sources: the post numbers in this thread.


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## Grader Johnny

Such an awesome thread with so much information in to about geometry and how they work thanks to Mikey and all the rest of you guys for sharing your knowledge to us newbies. I’m just marking out a RH turning atm but and having to wait to get a 8inch grinder next week. Link for the bench grinder I was looking at https://www.carbatec.co.nz/product/36686-carbatec-200mm-bench-grinder-slow-speed?categoryId=1506
Cheers Johnny


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## mikey

Grader Johnny said:


> Such an awesome thread with so much information in to about geometry and how they work thanks to Mikey and all the rest of you guys for sharing your knowledge to us newbies. I’m just marking out a RH turning atm but and having to wait to get a 8inch grinder next week. Link for the bench grinder I was looking at https://www.carbatec.co.nz/product/36686-carbatec-200mm-bench-grinder-slow-speed?categoryId=1506
> Cheers Johnny



That's a lot of money for a bench grinder. If you need that for other reasons then it should do fine but if you want this tool mainly for tool grinding then a smaller, more reasonably priced belt sander like this one might be a better option. It is only 1/3HP but if you use ceramic belts (available on Amazon) then it will grind HSS just fine. Moreover, you can put a CBN wheel on the other end and that will increase the versatility of the machine. 

Good luck and let us know how it's going, okay?


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## Aukai

That with a CBN wheel would be awesome.


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## Grader Johnny

mikey said:


> That's a lot of money for a bench grinder. If you need that for other reasons then it should do fine but if you want this tool mainly for tool grinding then a smaller, more reasonably priced belt sander like this one might be a better option. It is only 1/3HP but if you use ceramic belts (available on Amazon) then it will grind HSS just fine. Moreover, you can put a CBN wheel on the other end and that will increase the versatility of the machine.
> 
> Good luck and let us know how it's going, okay?


The one I was looking at Mikey is 350nzd which is $200 us, finding it hard with options down here can get the cheap 6 inch popular brands for nearly the same price but nowhere near the hp


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## mikey

OHH, my mistake ... NZD, not usd. Still, I would still go for the belt sander if I were you.


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## Gaffer

mikey said:


> That's a lot of money for a bench grinder. If you need that for other reasons then it should do fine but if you want this tool mainly for tool grinding then a smaller, more reasonably priced belt sander like this one might be a better option. It is only 1/3HP but if you use ceramic belts (available on Amazon) then it will grind HSS just fine. Moreover, you can put a CBN wheel on the other end and that will increase the versatility of the machine.
> 
> Good luck and let us know how it's going, okay?


For the ceramic belts, do you prefer a particular brand - a price:quality thing maybe?


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## mikey

Red Label - proven to work well, available on Amazon. 36 grit cuts fast, 100 grit smooths nicely and then you can hone on diamond stones after that. Works good!


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## Jim F

mikey said:


> Red Label - proven to work well, available on Amazon. 36 grit cuts fast, 100 grit smooths nicely and then you can hone on diamond stones after that. Works good!


This !!!!!!!
I got the assortment kit for my 1x42, they work great !!


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## Grader Johnny

mikey said:


> OHH, my mistake ... NZD, not usd. Still, I would still go for the belt sander if I were you.


No drama there Mikey, I’ve never been a fan of belt sanders tbh


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## riversidedan

bought this nice HSS form set last year and couldnt figure a couple out, so searched around the internet and seen some examples
so put them to use, right now have used some for examples  and made my own HSS tools,  works great so far.......thanx to the internet  figured out how to make  chip breakers  and yes I use a grinder......


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## Aukai

Much less dust than a wheel, especially if you need to dress the wheel. I put CBNs, and took off the dust makers, I also use the belt quite often as a first operation with HSS.


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## mikey

Grader Johnny said:


> No drama there Mikey, I’ve never been a fan of belt sanders tbh



I spent a decade grinding on a bench grinder so I know it will work fine for you if you go with that. However, I have since spent more than 20 years on a belt sander grinding lathe tools and I can tell you that I find belt sanders to be faster, more accurate, easier to use, cooler to grind with and far more efficient that any bench grinder I have used. I will never go back to using a bench grinder for grinding lathe tools.

In the end, go with what you think is best. If you do go with a bench grinder, consider Aukai's recommendation and look at CBN wheels.


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## Grader Johnny

mikey said:


> I spent a decade grinding on a bench grinder so I know it will work fine for you if you go with that. However, I have since spent more than 20 years on a belt sander grinding lathe tools and I can tell you that I find belt sanders to be faster, more accurate, easier to use, cooler to grind with and far more efficient that any bench grinder I have used. I will never go back to using a bench grinder for grinding lathe tools.
> 
> In the end, go with what you think is best. If you do go with a bench grinder, consider Aukai's recommendation and look at CBN wheels.


My gut is saying bench grinder I have looked in the CBN wheels $153 nz =87ish us so later down the track when I get semi ok at fringing tools I’ll upgrade.


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## Karl A

Grader Johnny said:


> My gut is saying bench grinder I have looked in the CBN wheels $153 nz =87ish us so later down the track when I get semi ok at fringing tools I’ll upgrade.


If you are inclined toward a bench grinder, then I recommend you read this article:





						Advanced Tool Sharpening
					

Sharpening Lathe Tools



					www.conradhoffman.com
				



The article explains the advantage of the hollow grind (concave surface) that grinding on a wheel gives for honing a tool. I see the advantage of hollow grind for the side and the end of a tool. I think that a flat grind is better for the top of a tool. 
One accomplishes a flat grind using a flat grinding surface, such as a belt on a platen, a disc, or the side of a grinding wheel. Regular grinding wheels are not designed for grinding on the side, though.


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## Grader Johnny

Karl A said:


> If you are inclined toward a bench grinder, then I recommend you read this article:
> 
> 
> 
> 
> 
> Advanced Tool Sharpening
> 
> 
> Sharpening Lathe Tools
> 
> 
> 
> www.conradhoffman.com
> 
> 
> 
> 
> The article explains the advantage of the hollow grind (concave surface) that grinding on a wheel gives for honing a tool. I see the advantage of hollow grind for the side and the end of a tool. I think that a flat grind is better for the top of a tool.
> One accomplishes a flat grind using a flat grinding surface, such as a belt on a platen, a disc, or the side of a grinding wheel. Regular grinding wheels are not designed for grinding on the side, though.


Thanks for sharing the article Karl looks like a good read so far. My thoughts were that because the wheel is already concave it would do some of the relief as it ground. 

John


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## mcdanlj

There are serrated rubber wheels in a variety of sizes meant for belt grinders. That way you can get both flat and hollow grinds with a single appliance, just changing the backing surface.


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## Karl A

mcdanlj said:


> There are serrated rubber wheels in a variety of sizes meant for belt grinders. That way you can get both flat and hollow grinds with a single appliance, just changing the backing surface.


I imagine that the greater flexibility of a serrated rubber wheel, compared to
- a wheel grinder, or
- a hard, flat platen on a belt grinder,
results in more rounding of the tool edges when a tool is pressed against the abrasive belt. I expect, though, that such rounding of an edge of the hollow grind is relatively easy to remove by hand honing on flat stones.

I imagine the following order of operation, for grinding a tool bit using both
- a belt grinder with a flat platen, and
- a wheel grinder or a belt on a serrated rubber wheel:
1. Using the flat platen on the belt grinder, with a course abrasive belt, do most of the metal removal: side, end, and top. (Aukai wrote above, "... I also use the belt quite often as a first operation with HSS.")                                                           
 2. Using a wheel grinder or a belt on a serrated rubber wheel, perform the hollow grind on the side and end of the tool bit. Use a fine abrasive wheel or belt.
3. Using the flat platen on the belt grinder, with a fine abrasive belt, finish grinding the top of the tool.
4. Using flat stones, hone the hollow grinds on the side and end of the tool bit by hand. Don't hone the top of the tool by hand, because of the risk of ruining the edges with a facet. If you want to hone the top, use a honing fixture -- such as the one described by Conrad Hoffman in his article "Advanced Tool Sharpening" (link in post #1,828).

Caveat: In this thread, Mikey describes using a belt grinder with a hard, flat platen, and hand honing on flat stones, to achieve sharp tools. I expect that achieving it requires some combination of talent and practice.  I am partly motivated to write this post by WobblyHands' statement in regard to honing: "Doesn't seem to be a skill that I have at the moment.  Not for a lack of trying.  But need to move on."(post #1,762)


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## Aukai

I have suffered with this, the right diamond plates, the right honing fluid, and relax, your not grinding the bit. It's a soft hone, and trying to be flat. Yes it's easier written than done, but it will come.


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## mikey

Karl A said:


> Caveat: In this thread, Mikey describes using a belt grinder with a hard, flat platen, and hand honing on flat stones, to achieve sharp tools. I expect that achieving it requires some combination of talent and practice.



The key advantage of a flat platen on a belt sander is that it produces flat faces that register well on the face of a flat stone, like a diamond stone. This makes it simple to hone each face, although I admit the end face can be harder because it is smaller so there is less real estate to register solidly on the stone. 

There is no trick to honing. Just take your time and focus on getting rid of the grind marks while keeping the involved face flat. i prefer to put cutting pressure on the pull stroke and i go slow so I don't lose the register of the face on the stone. I do all three faces like this, including the top face, and have no real issues doing so. My edges cut like scalpels when I'm done.

It may be true that i have no issues honing tools because I've done hundreds of them. If that is true then it should be true for most everyone so practice - you won't improve without working at it.


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## Grader Johnny

First go at grinding and the new grinder goes well in my view 8in 1HP spinning 1450rpm which yes is slow but give me more time to get it right.
Cheers Johnny


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## Grader Johnny

That’s the first one done.


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## Grader Johnny

As close as I could get to 60 degree threading tool. Now I stuffed up with the turning tool as it only has 10 degrees on the tool rest


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## ttabbal

Those look good! You're heading in a good direction. Don't overthink the angles, the rest being a few degrees off won't make it not work. Perhaps less efficient for some materials, but it'll cut. Heck, try both and see what your setup likes best.


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## Grader Johnny

ttabbal said:


> Those look good! You're heading in a good direction. Don't overthink the angles, the rest being a few degrees off won't make it not work. Perhaps less efficient for some materials, but it'll cut. Heck, try both and see what your setup likes best.


Thanks ttabbal 
Trial an error is the way to go. Just waiting to get some round bar to do some projects.


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## Karl A

mikey said:


> The key advantage of a flat platen on a belt sander is that it produces flat faces that register well on the face of a flat stone, like a diamond stone. This makes it simple to hone each face, although I admit the end face can be harder because it is smaller so there is less real estate to register solidly on the stone.
> 
> There is no trick to honing. Just take your time and focus on getting rid of the grind marks while keeping the involved face flat. i prefer to put cutting pressure on the pull stroke and i go slow so I don't lose the register of the face on the stone. I do all three faces like this, including the top face, and have no real issues doing so. My edges cut like scalpels when I'm done.
> 
> It may be true that i have no issues honing tools because I've done hundreds of them. If that is true then it should be true for most everyone so practice - you won't improve without working at it.


I tried the opposite last week: hand honing the ground face of a 3/16-inch tangential (AKA diamond) tool bit that had a very-hollow grind: I ground the face using a 1-inch diameter grinding wheel on a Dremel rotary tool. I didn't suceed in hand honing it evenly and flat. Other people recommend hollow ground surfaces for honing, but at least for me at this time it is not a panacea.

I find that I am able to hand hone the side faces of a tangential tool bit by pulling the tool bit along its long axis. I think that this little success confirms what you suggested: that hand-honing flat faces is a matter of degree of difficulty.

I can use my modified/improved 2x42-inch belt sander to grind tangential tool bits that end up with your recommended rake angles for cutting different materials. I set the table tilt angle to achieve the desired side rake angle, and I set the protractor to achieve the desired back rake angle (adding the tilt angles of the tool holder to the table tilt and protractor). I can avoid needing to hand hone the ground face by grinding with finer and finer belts, up to 800 aluminum-oxide grit.


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## Karl A

Karl A said:


> After having and using a 55-degree carbide-insert tool and an HSS RH knife tool for two years, I realized only this week that the tools are basically carbide and HSS versions of the same tool. The 55 degrees of the carbide insert is the same thing as the 35 degree end-cutting-edge angle of the HSS tool. One difference between them is that the carbide-insert tool has a few degrees of negative side-cutting-edge angle.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> View attachment 420318


Two other correspondences between insert tools and ground HSS tools are:
- 80-degree diamond insert tools and HSS tangential tools
- neutral-hand 55-degree and 35-degree diamond insert tools and HSS round-nose tools.


----------

