# Sharpening tools



## ed crumbpacker (Dec 12, 2020)

So here's my first question.  Whenever I see anybody talk about sharpening anything (lathe tools or other) they run over to a grinder and free hand it or use the rickety L-bracket tool rest held on by a hex nut.  Since you have a precision machine in a lathe or mill, why not chuck up a grinding wheel, put the tool in some type of tool post, and, running the machine at a slow speed, use the lead screw/cross slide to create a perfectly straight precision edge or better yet compound edges? (I realize you need some type of safety shield for doing this.)  What am I missing?


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## mikey (Dec 12, 2020)

Why would you even consider using an abrasive wheel on a precision machine tool? Those bits of abrasive grit WILL get all over your machine, even if you cover it, and that will lead to premature wear that is totally unnecessary. Besides, with even a little bit of experience it is simple to grind a lathe tool with clean edges. Moreover, if you actually understand what you're grinding, a belt sander or bench grinder can grind any tool geometry you require with little issue.


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## Cooter Brown (Dec 12, 2020)

I understand why you want to do this but I dont think your lathe ways are going to like this......   I like using my surface grinder to resharpen tools its very fast and accurate, usually only need to dust about .005" off to get a sharp edge again.......


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## mmcmdl (Dec 12, 2020)

Not a good idea Ed . If I can get Aukai to load a pic , I'll show you why !


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## mmcmdl (Dec 12, 2020)

So I just sent Mike a picture of the Clausing in here at work that I brought into my shop . This is what happens when you have a bunch of amatuer butchers using a precision piece of equipment . The ways are no longer ways ..........................................they're waves !


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## Cooter Brown (Dec 12, 2020)

mmcmdl said:


> So I just sent Mike a picture of the Clausing in here at work that I brought into my shop . This is what happens when you have a bunch of amatuer butchers using a precision piece of equipment . The ways are no longer ways ..........................................they're waves !





I need to see this


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## mmcmdl (Dec 12, 2020)

Cooter Brown said:


> I need to see this



If I told you how I feel about it ( on this site ) , I would be permanently BANNED !


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## Cooter Brown (Dec 12, 2020)

mmcmdl said:


> If I told you how I feel about it ( on this site ) , I would be permanently BANNED !




Trust me when I say we all understand....... Half my machines came from the previous owners with all the ways packed full of grease, absolutely no oil anywhere.....


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## Aukai (Dec 12, 2020)




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## mmcmdl (Dec 12, 2020)

Thanks Mike .  Now , about the lathe ...................ain't this some $h** . This is what I come into on nightshift every night . If they had to buy a new lathe out of THEIR pocketbook , I would think these idIOts would respect the machine a little more .


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## mikey (Dec 12, 2020)

Wow! You mean to tell me those guys still have their jobs?


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## mmcmdl (Dec 12, 2020)

I'm the only machinist in the maintenance shop which is where this lathe is . They are not permitted in the machine shop .  If they ever left a machine in this condition in the other shop , they would no longer be employed . I have some very nice Colchesters 20 ft away from me . I don't even worry about this 13" anymore , it's a lost cause .

What pizzes me off is , I brought this machine into the shop and it was in great condition . They had a POS SB lathe in here before that . The ways were so worn you prolly needed a taper attachment to cut a somewhat straight shaft !  Didn't take long to get this one to the same point .


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## mikey (Dec 12, 2020)

A SB13 is a nice machine. Sorry the one you brought in was treated so poorly. I think I would have had a "meaningful" discussion with whoever did that.


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## mmcmdl (Dec 12, 2020)

This is was a Clausing Colchester !  The upper etchelon didn't want the lathe in here in the first place because of someone not qualified getting injured . I just turn my eye and use the machine shop equipment .


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## mikey (Dec 12, 2020)

Oh, wow! Doing that to a SB would be tragic but to do it to a Colchester ... very not good. Sorry to see that happen but it underscores the point we've all been trying to make to the OP - best not to get abrasives anywhere on your machine and especially on purpose.


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## mmcmdl (Dec 12, 2020)

mikey said:


> Sorry to see that happen but it underscores the point we've all been trying to make to the OP - best not to get abrasives anywhere on your machine and especially on purpose.



Exactly my point   We have a grinder right next to that same lathe .  Where they get 'em at ? 

 at ?


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## mikey (Dec 12, 2020)

mmcmdl said:


> We have a grinder right next to that same lathe .



I'm not even going to try to guess about why this is. Even us hobby guys know better than that ...


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## Tozguy (Dec 12, 2020)

Ed, the problem of preventing stray grit from getting in the wrong places on a lathe notwithstanding, there is a matter of convenience. Tool post grinders are used on a lathe for specific purposes but require a set up procedure. So if you are in the middle of a turning job and need to sharpen the cutting tool, it is far simpler just to remove the tool and touch it up freehand on an appropriate grinder than to change the lathe set up for grinding and back again.  It is relatively easy to acquire the skill to sharpen tools freehand.



ed crumbpacker said:


> chuck up a grinding wheel, put the tool in some type of tool post, and, running the machine at a slow speed, use the lead screw/cross slide to create a perfectly straight precision edge or better yet compound edges?


As for mounting the grind wheel in the spindle I would need you to explain the set up you would use in detail. I can't imagine one that would be practical for most of the knives and tools I have to sharpen.


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## Canus (Dec 12, 2020)

Grinding a lathe bit does not have to be super precision in order to get a good cut.  Some folks seem to think lathe bits need to be ground to very tight tolerences just because they are used on a precision machine.  Not so.  A good free hand grind will produce a quality cut.


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## KMoffett (Dec 12, 2020)

How is the dust from a tool post grinder on a lathe handled?


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## Tozguy (Dec 12, 2020)

Grinding on my lathe involves putting covers on all parts on the lathe (picture a surgeon working on a patient who is covered everywhere except where the skin is cut). Special precautions for preventing grit getting into the chuck and spindle bore.
Then a thorough cleaning of the lathe after the grinding job is done, which might include disassembly and cleaning of the chuck.
Measures also might need to be taken to cover other machines and equipment in the proximity.


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## Logan Novice (Dec 30, 2020)

Aukai said:


> View attachment 346961


Makes ya want to cry ......   
I made a tool post grinder setup for my lathe.  As soon as I finished it, being satisfied that I could actually do it, I dumped it into the scrap bin.  It was a good exercise in angular machining and adaptation of powered accessories for the lathe but I would never use it.  Call me wasteful; I can handle it.


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## Aukai (Dec 31, 2020)

Just to clarify that is Dave's lathe at work, not mine. I posted for him....


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## mmcmdl (Dec 31, 2020)

I actually had to run that lathe tonight . I'm not too concerned about the ways after hearing the spindle bearings !


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## Aukai (Dec 31, 2020)




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## ed crumbpacker (Jan 1, 2021)

Well I want to thank everybody for their replies...so my next question would be about the people I see chucking up a piece of wood, turning it, then sanding it.  Wouldn't saw dust be just as bad or are you more worried about the grit from a stone than metal dust from grinding?  I've also seen people using emory board type things to sand/polish brass, what's your thoughts?


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## Tozguy (Jan 2, 2021)

Its the flying abrasive grit that bothers me. Metal and wood chips, even the dust from cutting cast iron, are not as hard and abrasive as grit that is designed for metal removal.
Grind stones are usually spinning quickly and flinging its abrasive material everywhere. Sandpaper, Scotchbrite, etc. on the other hand do not fling anything and often will load up and make it easier to control debris.


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## tjb (Jan 2, 2021)

Here's what you need to do if you're turning abrasive material - like a cast iron back plate:








Even then, you better be thorough in the cleanup.

Regards,
Terry


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## dbb-the-bruce (Jan 2, 2021)

Ok, I get it - abrasives particles and precision surfaces don't mix if you want the surfaces to stay precision.

So has everyone here thrown out or packed away their tool post mounted grinders forever? Logic would seem to indicate that these grinders are useful and desirable equipment otherwise they wouldn't be produced and sold.

Seriously, there are acceptable uses for grinders in combination with a lathe without serious damage to the lathe if the right precautions are followed.

I only have one direct experience using a grinder on lathe to correct the fit of large external threads on a hardened part. This was done by a very knowledgeable gentleman on a museum pice of a lathe. Reasonable (not excessive) precautions where taken to protect the lathe and to clean up afterwords.

I am interested in hearing more - I have an original equipment tool post grinder that I have considered using on occasion but have avoided doing so for lack of experience and fear of messing up my lathe.

I think there may be a little "throwing the baby out with the bath water" in some of the comments in this thread.

Interested in learning more!


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## tjb (Jan 2, 2021)

dbb-the-bruce said:


> Ok, I get it - abrasives particles and precision surfaces don't mix if you want the surfaces to stay precision.
> 
> So has everyone here thrown out or packed away their tool post mounted grinders forever? Logic would seem to indicate that these grinders are useful and desirable equipment otherwise they wouldn't be produced and sold.
> 
> ...


Personally, I think it's a little more like throwing out enough of the bathwater so the baby doesn't drown.  I have no experience with tool post grinders, but I can attest to the fact that when turning cast material, dust is created that gets everywhere - nooks and crannies in your equipment that you didn't even know existed.  Think Etch-a-sketch size powder.  Here are some shots of my lathe during the operation from my earlier post.  I wish I had thought to take some pictures during the clean-up.  You'd be able to see how fine the particulate was.  Difficult to tell, but if you zoom in, you'll see some relatively finer particles on the insert, tool holder and tool post.

The first picture was before I started turning.  It became apparent pretty quickly that the fine particles would be significant.  I did not want to remove the tape with a build up of that dust, so I repositioned it inside the plate with loads of packing material behind it.  The film you see on the back plate in the subsequent pictures is fine dust from the turning before I removed the tape.









The stuff you see on the towel was the heavier particulate matter.  The finer dust was pretty much everywhere - some you couldn't see on the towels, but you could pick it up with a magnet.  I'd hate to think that stuff was anywhere near the spindle.  Those towels ended up in the garbage.

After turning, I needed to drill mounting holes using my mill and rotary table.  Even that produced a fair amount of granular crud but nothing on the order of the stuff on the lathe.

A good argument could be made that what I did was overkill.  I'll spot you that.  But it was recommended to me by one of our highly-respected resident experts.  I'm glad I followed his advice because he was right.  Like they say - better safe than sorry.

Regards,
Terry


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## Tozguy (Jan 2, 2021)

dbb-the-bruce said:


> Reasonable (not excessive) precautions where taken to protect the lathe and to clean up afterwords.


There are probably as many opinions about what is excessive and what is reasonable as there are members. The beauty of the question is that we can discuss it excessively.


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## dbb-the-bruce (Jan 2, 2021)

@tjb - I've heard that cast iron can be really nasty and that it can create a lot of nasty, abrasive dust. I've only turned cast once (face plate) and it didn't create that much of a mess. I agree - one should take appropriate precautions for the long term protection of their lathe - whatever they are turning or grinding.

The original poster was specifically asking about grinding / sharpening tools. It seems that tool sharpening would not be removing a lot of material and maybe using a small wheel on a tool post grinder wouldn't make as much of a mess and turning cast iron. Position a shop vac really close to suck all the dust up at the source maybe. Protection and clean up shouldn't be that bad.

What do people do when they use tool post grinders? and what to they use them for?


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## mikey (Jan 2, 2021)

dbb-the-bruce said:


> The original poster was specifically asking about grinding / sharpening tools. It seems that tool sharpening would not be removing a lot of material and maybe using a small wheel on a tool post grinder wouldn't make as much of a mess and turning cast iron. Position a shop vac really close to suck all the dust up at the source maybe. Protection and clean up shouldn't be that bad.
> 
> What do people do when they use tool post grinders? and what to they use them for?



I suppose it comes down to a personal choice. While you CAN sharpen tools on your lathe with a grinding wheel, why do that and risk your lathe when other machines and methods can do it better? A bench or belt grinder, a little skill and you're done.

A tool post grinder is an attractive attachment but it is most commonly used to produce precision dimensions on hardened material. How often do you do that? They can also be used to true up chuck jaws; how often do you do that? I don't own a tool post grinder but it was an intellectual choice not to buy one because I weighed the risk to my lathe vs the situations listed above. 

If you own a tool post grinder and wish to take the chances with your lathe then go for it. Lots of other hobby guys do this so you aren't alone.


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## dbb-the-bruce (Jan 2, 2021)

mikey said:


> If you own a tool post grinder and wish to take the chances with your lathe then go for it. Lots of other hobby guys do this so you aren't alone.



Ha! It came with the lathe. So far all I've done with it is make an attachment to hold an 60 deg engraving bit and then use it to cut threads on wood parts.

This thread got me thinking about using it as an actual grinder. Apparently, hardly anyone grinds on their lathes. I did see one of the YouTube guys use a grinder on the inside of a cylinder that needed to be precise


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## Jim F (Jan 2, 2021)

mikey said:


> I suppose it comes down to a personal choice. While you CAN sharpen tools on your lathe with a grinding wheel, why do that and risk your lathe when other machines and methods can do it better? A bench or belt grinder, a little skill and you're done.
> 
> A tool post grinder is an attractive attachment but it is most commonly used to produce precision dimensions on hardened material. How often do you do that? They can also be used to true up chuck jaws; how often do you do that? I don't own a tool post grinder but it was an intellectual choice not to buy one because I weighed the risk to my lathe vs the situations listed above.
> 
> If you own a tool post grinder and wish to take the chances with your lathe then go for it. Lots of other hobby guys do this so you aren't alone.


I rigged up a Dremel to grind chuck jaws, probably never use it again.
Very messy and lots of clean-up afterwards..........


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## tjb (Jan 2, 2021)

dbb-the-bruce said:


> The original poster was specifically asking about grinding / sharpening tools.


Yeah, I caught that.  Like I mentioned, I have no experience with tool post grinders.  But the thread rather rapidly expanded to issues of grinding dust in general.  That's the part I was commenting on.

Regards


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## Tozguy (Jan 2, 2021)

A tool post grinder can't be beat for grinding jaws in situ but for sharpening tools there are so many other better machines designed for that type of work. How useful a tool post grinder can be depends on the jobs you have to do. I have only used mine once in seven years but I like having it on hand if it is ever needed again.


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## stupoty (Jan 2, 2021)

tjb said:


> I can attest to the fact that when turning cast material, dust is created that gets everywhere - nooks and crannies in your equipment that you didn't even know existed.




It's true , cast iron is so nice to turn but the mess can be insane.



Stu


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## Winegrower (Jan 2, 2021)

Relating to the original question, Joe Pie has a video showing making a hex (I think) rotary broach with a cupped grinding wheel held in the mill spindle.   He lived.   So did the mill.


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