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Models for grinding HSS Lathe Tools

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Aukai

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I think it did add some stiffness to it.:)
 

Bob Korves

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shorton

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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

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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.

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

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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?
 

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mikey

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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

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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
. 8ABE7BCB-7D03-46C7-8418-7816F5218907.jpeg 7862F7DA-3A29-411E-8DC6-52AF6B8F764A.jpeg 0DF96D33-4CF7-4D68-A25C-9F9B979353A3.jpeg D4BD0210-A9BA-4A9A-BD65-4F52F7AD4002.jpeg 8ABE7BCB-7D03-46C7-8418-7816F5218907.jpeg 7862F7DA-3A29-411E-8DC6-52AF6B8F764A.jpeg 0DF96D33-4CF7-4D68-A25C-9F9B979353A3.jpeg D4BD0210-A9BA-4A9A-BD65-4F52F7AD4002.jpeg

Critiques?
 

mikey

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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

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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

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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

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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.
IMG_1181.JPG IMG_1182.JPG IMG_1183.JPG IMG_1185.JPG IMG_1186.JPG

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.
IMG_1187.JPG
 

mikey

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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

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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!

IMG_1192.JPG IMG_1193.JPG



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

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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

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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. :)

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

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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

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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

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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
 
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Z2V

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I have a set of model tools available if anyone is interested. PM me if you would like to see them.
 

TerryH

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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. :grin: I'll bring my sander. Should be an interesting conversation piece as a carry on. lol...
 

ttabbal

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Given your location, I think we should reconvene this discussion to your house ASAP. :grin: 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.... :D
 

mikey

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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!
 

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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!

20180702_173549.jpg 20180702_173523.jpg 20180702_173503.jpg 20180702_173242.jpg

This is before being honed.
 

ACHiPo

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Nice job!
 

mikey

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Under the circumstances, not sure I could have done it any better. Good job!
 

Z2V

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Looks really good considering what you had to work with.
 

Esmith41

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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. 0CB71BD9-AEB7-4F70-A76D-6E0CC9752704.jpeg 215533B3-2C35-40A7-B49D-59CA4204A365.jpeg 8A9BDD80-7E43-4BE1-BCEB-ABEF474EB481.jpeg Now I just need to learn how to use them.Thanks again guys!!
Eric
 

Headrc

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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
 

mikey

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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!
 
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