curious question about diff steels and sharpening

harkamus

harkamus

Joined
Apr 23, 2007
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I have read a couple posts saying that s30v is harder to sharpen than some other knives because the steel is so hard. However, most decent bladesteels are all heat treated around the same rockwell hardness of 58 - 61 or so...so my question is how can one one steel be harder than the other if they're the same rockwell hardness? Say something like 58 - 61 RC 154cm vs. 58 - 61 RC s30v vs. 58 - 61 RC d2.
 
harkamus said:
I have read a couple posts saying that s30v is harder to sharpen than some other knives because the steel is so hard. However, most decent bladesteels are all heat treated around the same rockwell hardness of 58 - 61 or so...so my question is how can one one steel be harder than the other if they're the same rockwell hardness? Say something like 58 - 61 RC 154cm vs. 58 - 61 RC s30v vs. 58 - 61 RC d2.
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Bold for emphasis. Good catch, the difference isn't the hardness of the steel- people who say that are misusing terminology. It happens.

As was pointed out by reader, the difference is carbides. The general rule is, more carbides = more abrasion resistance = more difficult to sharpen.
 
Reader and Greg have explained it well. S30V is more wear resistant than some other knife steels. That's what helps it keep it's edge as well as it does, but it also means that sharpening is going to take more time. Not more pressure, mind you, just more time with the same pressure. Let the stones do the work and just realize that they will work a bit more slowly with some of the high wear-resistant knife steels.
 
Excellent explanation people. Now off to find a cheap Sharpmaker. I think I will practice free hand on my Global chef knives, although I'm pretty confident in my ability to keep a steady hand and the blades straight.
 
previous threads correct.complex steels have various carbides .amount and heat treatment contribute to wear factor. vanadium carbides can be 70s 80s rockwell.
 
harkamus said:
Excellent explanation people. Now off to find a cheap Sharpmaker. I think I will practice free hand on my Global chef knives, although I'm pretty confident in my ability to keep a steady hand and the blades straight.
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Just an extra note on Globals. I really like the Globals and MAC's. The MAC's seem to fit my hand better.

I have some MAC knives (a paring knife, and an 8# Chef's). IMO the steel is very similar to the Globals with both containing vanadium at about the same hardness. All the Western style Japanese Globals (and MAC's) I have seen have a thin convex edge. Probably because they finish them on belt grinders. However, Global recommends sharpening them on stones once you get them (probably because that is more common in the field).

I have experimented with flat bevels at varying angles down to about 10° per side. While they work great with flat bevels, at anything less then about 13° I get some micro chipping when my wife uses them although they work fine for me. Probably the way she works with a cutting board, doing come twisting and chopping. I have recently gone back to convex edges and a very thin (acute) angle and they hold up better for my wife and still push cut and slice about the same (extremely well) for me.

Gary
 
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