Sharpening M2 vs. Powder Metal

[Craig Powers]

Can you get the same results sharpening M2 and powder metal steels?
My perception is that I can't get my powder metal tools as sharp as the M2 tools.
Does a water cooled grinder such as a Tormek get either one sharper than the standard 8 in bench grinder set up.
Thanks for responses.

[Wyatt Holm]

Well that is the advantage and drawback of the two. M2 will get sharper, but it does not last as long as the powder steel. A lot of people use the powder steels for roughing cuts. Then get a smaller M2 steel for finish cuts.

[Ken Fitzgerald]

Craig,

I have a Ellsworht Pro-PM bowl gouge. I just used it again for maybe the 2nd time and decided I'd try sharpening it. It sharpened just fine and I was surprised by the nice curlies I was getting out of the semi-dry piece of walnut I was turning. It seemed to cut cleanly to me.

[Craig Powers]

Thanks for the reply Ken. Do you use the Ellsworth jig to sharpen
the gouge?
Also, what grit wheel to you use? High speed or slow speed grinder?

[Ken Fitzgerald]

I use an 8" Woodcraft slowspeed grinder....120 grit wheel......Wolverine vari-grind sharpening jig. I had the first opportunity to use the bowl gouge a couple of weeks ago on the outside of a HF I was turning. Then this past weekend I used it again to turn the semi-dry walnut. It works well.

I use a magic marker to coat the original grind....then set up the vari-grind to take off the "wing coatings" and the "nose coatings" properly...then just grind it. I find I have to pay attention to taking enough off the nose as it's easier to grind too much of the sides/wings.

[Bernie Weishapl]

Craig I now use a Tormek for sharpening my tools and I find the PM tools are as sharp for sure and maybe sharper than M2. I do find that the PM holds their edge longer. I don't have to go back to the grinder as often. This is just a observation that I have found in my sharpening and turnings.

[David Walser]

1.) Do powdered metal tools get as sharp as M2 tools? The answer is that it depends. The theory is that the grain structure of PM is larger than M2 steel. Therefore, while PM may be harder, the larger grain structure prevents it from getting as sharp. That may be true for some PM steels. Thompson claims his tempering process not only converts more of the steel into carbide (which makes its edge longer lasting), it also refines the grain structure of the steel allowing it to be ground to a finer edge. Other manufactures of PM tools use different tempering methods -- and obtain different grain structures -- so the edge you can get may vary from one brand to another (even when the "type" of steel is the same). Having said all that, most users of PM tools notice little of any difference in how sharp they can get the edge. Most report that the edge lasts longer. YMMV.

By the way, this reminds me of the discussion that took place when turners were first converting from high-carbon steel tools to high speed steel tools. Many claimed high-carbon tool steel got sharper than HSS. In retrospect, it may have been that turners had learned how to sharpen their high-carbon tools and that those skills did not translate perfectly to sharpening a tool made from HSS. Today, you seldom hear a turner say he uses his HSS tools to rough out a blank and then uses his high-carbon tools for finish cuts. Back in the day, you heard that all the time.

2) Does sharpening with a Tormek produce a sharper edge than sharpening on a dry grinder? Yes. The Tormek's wheel is 220 grit. It can be "graded" to "convert" the wheel to 1,000 grit. Properly done, an edge off a 1,000 grit wheel will be sharper than one off of an 80 grit wheel. Some will argue that the difference in sharpness does not make a difference in turning. I would disagree, but that's a different question.

[Scott Conners]

I find the steel in my Thompson 1/2" V to be more brittle - it takes a finer wheel and lighter touch to get the same smoothness of the edge. It tends to have lots of micro teeth if I don't use a fine grit wheel and sharpen carefully. I find that off my 150g wheel it gets plenty sharp enough. I hone4stly havent' noticed a huge difference in how long the edge lasts, though that may be because I don't have a comparable tool to the Thompson in HSS, so can't do an apples to apples test.
I have noticed a slight difference in how sharp I can get the edge honing my Thompson skew, but that may be due in part to the curved edge, which I'm still figuring out how to hone by hand. My Sorby and even my HF skews with straight grinds definitely get to super sharp much easier, though the HF definitely loses the edge much faster.

[Craig Powers]

David. Thanks for the reply. Good info. I guess what I'm getting at, is it worth it to get a Tormek to sharpen(esp. the powder metal tools)? Granted the Tormek will certainly do more than just that.
To muddy the water a little more, Henry Taylor now has the Kryo line. Which to my understanding is just cryogenically treated M2. There are claims of best of both worlds(sharpness and edge retention) with those.

Bernie. Thanks. Sounds like a logical thing to do. Just wondering about the cost/benefit ratio. Or maybe looking for an excuse to save for a Tormek.

[curtis rosche]

is there a big difference between the sharpness of m2 and a thompson gouge? and are there any special things to do when sharpening?

[Craig Powers]

Curtis, I may be wrong, but I think Thompson tools would fall
under the category of powder metal. And I was trying get the answer
to your questions as well.

[David Christopher]

Craig, I have the jet clone of the tormek and I think it is worth the money to have a slow speed/ water machine...my lathe tools seem to stay sharper longer and it works great on other tools as well ( hand chisels, scissors, planed/jointer blades etc. etc ) if you decide to get one you wont regret

[Bill Bolen]

I am back and forth between a dry grinder and a Tormek. I have to agree 100% with Bernie on this one...Bill..

[David Walser]

... I guess what I'm getting at, is it worth it to get a Tormek to sharpen(esp. the powder metal tools)? ...Short answer: I have one and would buy it again in a heart beat.

Longer answer: Take a close look at this article from UK's Woodturning: http://www.tormek.com/en/leaflet/pdf/wet_or_dry_en.pdf. The article has pictures of the edge straight from a dry grinder, straight from the Tormek, after honing from a dry grinder, and after honing from the Tormek. It's clear that the Tormek's edge, after honing, is the sharpest of the four edges pictured. It's also clear that the Tormek's un-honed edge is sharper than the dry grinder's honed edge!

Does this extra sharpness make a real difference in the real world of turning at the lathe? I think it does. I'm a better turner since I started sharpening on my Tormek. I have more control of the shape I'm creating, I get fewer catches, and I get a better surface off of the too. But I freely admit that I may just have become a better turner with practice. It might also be that using the Tormek's jigs has given me a more consistent tool shape and that it's the constent shape, not the sharper edge, that's enabled me to improve my turning. (I was using a Wolverine-like jig with my dry grinder. Even with the use of the jig, after each sharpening the shape of my tool would be a little different than it had been after the last sharpening. The Tormek jig produces a more consistent shape because the jigs have less "play" in them and because you're removing less metal with the slower water cooled wheel.) Bottom line: Alan Lacer, Stuart Batty, and lots of the members of this forum, are better turners than I am and they don't use a Tormek. So, the sharpening system does NOT make the turner!

Still, on another thread, the poster wrote about how thrilled he was because he was finally getting good cuts from his new bowl gouge. Seems he was learning to use his Wolverine to produce a sharp tool and sharp is way better than dull. Well, my experiance is that really sharp is better than fairly sharp. I got a decent edge from the dry grinder with the use of my jig and I was fairly happy with it. I was getting better at sharpening and keeping the shape of the tool fairly consistent from one sharpening to the next. Still, it was frequently an adventure learning how to present the tool exactly right after returning from the grinder. It might take a cut or two before I was getting the clean cut I was after. This made "sharpening before taking the final finish cut" a real adventure!

One final thing and I'll close out this overly long post: Take a look at the graphs that compare the cutting ability of a dry ground tool and a wet ground tool over time. The wet ground edge is sharper and it's more efficient at removing wood. That may have been expected. The question is did this advantage disapear almost as soon as the steel touches the wood? No. The wet ground tool remained sharper and cut more efficiently for the entire time period tested. That is, the dry ground tool (per the graph) was able to cut hardwood efficiently for a period of just short of 10 minutes. The wet ground tool was still cutting efficiently after 15 minutes and was still cutting more efficiently at that time than the dry ground tool had at 10 minutes. In pine, both edges were able to cut efficiently for more than 15 minutes. However, at that time, the wet ground tool was still cutting better than the dry ground tool ever had and the wet ground tool was increasing its advantage over the dry ground tool. This jives with my experiance: the edge I get off my Tormek cuts better and lasts longer than what I got from my dry grinder. It's not close.

[Kyle Iwamoto]

LOL

I just wanted to add that my next tool want is a Thompson gouge, and I already have a Tormek. But to answer the original question, this is indeed like the Carbon Steel and HSS comparison. I think I can get my CS tools WAY sharper than the HSS tools. But the CS tools dull very quickly. You may be able to get HSS sharper, but not last as long as PM. So, it looks like PM tech has finally gotten to lathe tools, and it looks good. But, is it alreay outdated by Carbide? Referring to the Easy Rougher, Hunter Carbide etc......

Another thread? Steel vs Carbide?