How to grind a HSS toolbit for a metal lathe

[Petromax]

Hello guys,

I was wondering how to grind/sharpen HSS toolbits for my metal lathe. These bits are quite complicated to grind because there are many important angles. Has anyone find out a technique for this job?

https://youtu.be/Mn9jpqI8rao


Regards

[Jan]

I have never sharpen metal lathe tool bits on Tormek. 

In my understanding Tormek is not suitable for it. Some edges could be touched from the Tormek Tool Rest, but you will get hollow grinding. To grind a flat surface, you would have to use the outside of the grindstone, which however cannot be trued.

Jan

[Elden]

http://forum.tormek.com/index.php?topic=1428.msg4484#msg4484

   Paul, Ken has experiented using a Norton grinding wheel on the Tormek with lathe bits.

http://forum.tormek.com/index.php?topic=2527.msg13047#msg13047

   As was mentioned, I believe the SVD-110 tool rest could be used. The first lathe bit I formed was done free hand on a dry bench grinder years ago. As I recollect, it was done on the face of the wheel, not the side of it.

[jeffs55]

I am glad that Jan replied. I was going to ask are HSS tool bits cheaper than carbide inserts?

[Ken S]

Petromax,

From time to time, I have read posts here by members who have had good results sharpening  metal lathe tool bits. However, those who did it did not have the digital/photo skills to post how to do it. We routinely sharpen skew chisels with two angles. I have no doubt that a clever machinist could sharpen metal lathe tool bits with a Tormek.

With all due respect to Jan, I do not believe the minimal amount of hollow grinding from a 250mm or 200mm grinding wheel is a problem. We use these wheels to sharpen drill bits. Many years ago, I watched a machinist sharpen tool bits using a six inch (150mm) dry grinder. I do not recall him using the side of the wheel. From recent posts, I also believe the side of the Tormek wheels can be dressed flat, or at least adequately flat.

I have ground metal lathe tool bits with my Tormeks, both the T7 and the T4, as part of a wheel comparison test. The SG wheels gave adequate performances. The Norton 3X wheels did very well. Looking at some of the recent Tormek jigs, and those built by forum members ( including Jan ), we are not far from developing the jigs for metal lathe tool bits if we apply ourselves. Perhaps those who posted good results would post again.

Ken

[Petromax]

Thanks for your replies. It is not a problem that the surfaces are a little hollow, this also happens with a normal bench grinder. Carbide bits require a very high cutting speeds and are therefore not always useable.

I just bought the SVD-110 and I hope this jig helps me to find a method for sharpening my HSS toolbits, otherwise I have to develop my own jig. I thought there was an easy way...

I'll let you know if I found something usefull.

[Ken S]

Best of luck, petromax. Just because Tormek does not happen to manufacture a jig (at this time) for metal lathe tool bits does mot mean that sharpening them is outside the scope of the Tormek. Give it a go, and do keep us posted!

Ken

[Elden]

   Wish you well, Paul. Are you sharpening an already formed cutter or making one from a blank HSS stock piece? Years ago in vocational technical school was when I ground the one I mentioned. It was done using a standard bench type grinder.

[Petromax]

   Wish you well, Paul. Are you sharpening an already formed cutter or making one from a blank HSS stock piece? Years ago in vocational technical school was when I ground the one I mentioned. It was done using a standard bench type grinder.

I make them from blank square toolbit steel.

[Rob]

No one's mentioned the Silicon Blackstone wheel??  That's designed for sharpening HSS.  It was really aimed at woodturners using HSS chisels and gouges and is harder than the regular SG stone.  Doesn't answer the jig question but the stone is purpose built for that specific alloy.  At least I think it is???