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Models for grinding HSS Lathe Tools
- Thread starter mikey
- Start date
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:
Sitting on the box they will travel in to Hawaii:
And here they are before they were finished:
- Joined
- Dec 20, 2012
- Messages
- 9,422
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.
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.
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!
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!
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- Dec 20, 2012
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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.
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.
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 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
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
- Joined
- Dec 20, 2012
- Messages
- 9,422
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.
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