Difficulty in grinding M2 vs V10

[Chris Barnett]

Have the opportunity to replace Ellsworth M2 bowl gouge with Ellsworth PM gouge, but not sure it is the V10 recipe. Looking at the toughness vs hardness data provided previously by another member, the M2 has the same toughness value as the V10 [a good thing] but the hardness of the V10 PM steel is considerably higher than the M2. I would not want the higher hardness at the sake of impact resistance (broken tools) but based on their information, all is well.
But, now to the question: for those who have the PM tools, and particularly the V10 if you know your material, what is the difficulty in sharpening the V10, say....on a Wolverine? It seems just a trade off in material loss (M2) vs time V10, but if the V10 is beyond reason in time, would the M2 be suitable for the casual user....hobby use only. This is really a question of opinion. If the wood dries out before I can get the tool ground, perhaps I should stay with the M2 :D.
Also, would the V10 be a wiser choice for scrapers etc. in additon to gouges?
And perhaps another question: has anyone broken a [hesitate to use this term but expensive is really not the correct word] quality PM tool?

[Dick Latshaw]

My tools range from Harbor Freight M2 to really good V10 from Doug Thompson. I have noticed no major difference in sharpening on my Woodcraft grinder with the Wolverine guide. I do have Norton 3X wheels on the grinder.

If Mr. Thompson ever gets some scrapers back in stock, I'm in the market.

[Cyril Griesbach]

I'm with Dick on this issue. I experience no difference in sharpening my variety of Sorby and Crown M2 and Thompson V10 tools. I also use a Wolverine with vari-grind as well as the Geiger Solution for the Ellsworth.

Cyril

[Gordon Seto]

I don't know what Rc hardness Doug Thompson tempers his tools to. From the data sheet, the steel can be made to different hardness with different cryogenic treatment temperatures. For turning wood, we don't need something that is extra hard, we value the wear resistance of the V10 steel, which is several folds over the regular M2 steel.
http://www.crucibleservice.com/datash/ds10Vv7b.pdf
And I think the Q&A here answers a lot of your questions:
http://www.thompsonlathetools.com/faq.asp
I believe Stuart Batty is the one who brought the V10 as negative rake scraper to the fore front. The negative rake scraper (NRS) relies solely on the burr of the tool. In his demo, he had a handful of Sorby beading and parting tools sharpened lined up for use. He said the burr would only last about 3 ~ 4 second. He got a silky finish. On the inside, he can't use the beading and parting tool on his tall vessel. He had Jerry Glaser special made for him some NRS made from V10 steel. He used them un-handled. He just wrap duct tape at the end for holding. He said the V10 would last a lot longer. He had only one of the NRS. He sharpened it before last cut. He also said the V15 is supposed to be more durable, but the burr broke off.
Stuart makes a task looked easy, mostly because of him. Don't expect the same result, simply because we are having the same lathe or tools. If you have a chance, watch him at demo or take a class from him. He had a thin bowl reversed in a jam chuck. It was already very thin. He lightly tapped the bottom of the bowl, and said, "a little bit thick here, one more cut." I think most sane demonstrator won't take that risk without the ability to seeing or measuring the wall.

[Jim Becker]

One of my three Ellsworth format gouges is the Crown PM version. I've had zero issues with sharpening it as compared to my original Ellsworth gouge or the re-engineered Sorby ground "similarly" using the Ellsworth jig.

[Doug Thompson]

Let's break this down and discribe the different facts.

Steel - most steel is made by melting all the different elements and pouring in a mold/form, it is then rolled hot or cold to create the final size. Powder steel is when each element is made into a powder form and mixed together then heated just enough so the elements bond to each other. This is a way to disperse the elements very evenly throughout the steel, this creates a high quality steel that can't be done any other way. The down fall is it's expensive to do.

Elements that make up steel is what we need to look at. We know carbon steel is the most common steel made but it's not good for woodturning. To the other extreme tungsten (carbide) it the most durable but doesn't make a good woodturning tool. Cobalt is in steel to add high temperature strength when machining steel, what we see is a better quality HHS when cobalt is added. Vanadium is what adds toughness to the steel we use, M2 has less than 2%, 2060 has about 6% and A11 has 9.75% This is what we need to hold an edge.

The heat treatment is another thing we need to look at. There are two ways to harden steel for woodturning tools. The most common is done with a induction heater, this is done by putting the steel in some coils, the coils turn red hot and therefore the steel inside. In a matter of seconds the steel is up to temperature then dropped into oil, this is done by timing, it's very interesting to watch and very cheap to do. The other way is to place the steel in a oven, slowly raise the temperature then slowly drop it, this will take 8-10 hours.

My statment to everyone...
When a tool is hardened with a induction heater first the flute is only hard the first 4-5 inches. Second the shank is soft and manufactures say this is for your safety.

Now think about this...
What tools always break or bend?

Answer... the tools hardened with a induction heater! The same ones that are sold to be safe. This is a cost saving process.

Did you ever hear of a Glaser tool breaking? Not a single one I sold broke.


Just maybe a soft shank is not so safe after all.


To answer your question, any grinding wheel will do.