Models for grinding HSS Lathe Tools

[finsruskw]

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]

Are there drawings/prints of these cutter bits available anywhere?

I created models in OpenSCAD and put them on thingiverse but:

1. 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.
2. OpenSCAD doesn't have a feature for making prints.

Nevertheless, the models might help someone else make prints.

 

[finsruskw]

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]

I created models in OpenSCAD and put them on thingiverse but:

1. 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.
2. 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.