Question about Sharpening

[JeremyW]

I've just bought a Benchmade knife, and I've noticed that in the enclosed booklet they say not to sharpen the knife on a grinding wheel, as this will burn the temper out of the edge. Is this really a concern for high speed/temperature steels like M2 and ATS-34? Also: am I going to get a surprise the first time I try to sharpen the knife on a whetting stone? I do a fair job with cheap kitchen knives, but I've heard that high-carbon knives (aka: real knives) can be difficult to sharpen.

One other sharpening-related question:

A long while back I was given as a gift a handmade 440C knife from France with an extremely thin blade. The blade has a mirror finish, and the edge of it is beyond sight: it looks like it was never sharped and the blade just ends without a grind. I've seen knives with thin edge grinds, but the one on this knife can only be seen as a brief flash under a bright light... if you move it around for a while and look hard. How on earth do they do that?? It's the sharpest knife I've seen but I'm scared to death of using it. I could never put the edge back on it as it's supposed to be.

-Jeremy

 

[Jeff Clark]

The Benchmade warnings are primarily not to use a metal shop grinding wheel on the blade. This is likely to marr the blade and maybe overheat and soften a thin part of the edge or tip. It can happen on almost any alloy. If you somehow excessively dulled the blade it would be better to do rough sharpening with a belt sander than a grinding wheel (unless you are very skilled).

Since M2 is hard and tough I would consider getting a diamond-coated hone for sharpening. If you are comfortable with a bench hone, I would get one of those at least 6 inches long and probably medium grit. If you aren't comfortable with the bench hone I would get something like a v-style hone from AG Russell. He sells a small "field sharpener" that has both ceramic and diamond-coated rods. This would work on your M2 blade as well as your French knife.

In general a v-style ceramic sharpener would work fine on your French knife's fine edge. Go ahead and use it.

The Russell sharpener can be seen at:

http://www.agrknives.com/maintenance/index.html



[This message has been edited by Jeff Clark (edited 05-08-2001).]

 

[Chang]

Some people use a belt sander to sharpen their knives, but they always cool it down in cold water after every single pass, because power tools generate a lot of heat from friction. I've read that M2 can handle high temperatures much better than most other steels without becoming annealed, but I'm not sure it would be smart to use a bench grinder. I've generated enough heat with a 6" bench grinder (3400 RPM) to turn steel red hot.

M2 and ATS-34 will be harder to sharpen than most cheaper steels. It will take longer because the steel is more wear/abrasion resistant.

You can probably sharpen the 440C handmade knife from France on a leather strop, assuming you don't ever severely dull it. You might consider getting an Edge Pro system with extra/ultra fine stones and polishing tapes. They can mirror finish an edge and be set to about any angle you want. If you have trouble sharpening knives well by free hand methods on a sharpening stone, the Edge Pro would help you out a whole bunch. Gives you the angle you want, and you can finish the edge really really sharp.

I sold my Edge Pro, and I'm still kicking myself for it. That was the best sharpening system I ever had. Worked much faster and better on 154-CM/ATS-34 blades than the other sharpening sets I used (Smith's, Lansky Deluxe, Razor Edge Professional, free hand on various sharpening stones).