TESTING Spyderco S30V vs. VG10

[Cliff Stamp]

Intuitively, a coarse edge (or very coarse, large grain) acts like tiny serrations and will rake through fibrous materials better. However, the coarseness potentially sets itself up with multiple tiny stress risers, making the coarse "teeth" prone to breakage and premature edge failure.

With a coarse edge you can drop the force required on a draw by several times over compared to a high polish, and thus even though the teeth are weaker, they don't experience the same force anyway, plus the cutting ability is so much higher they need to degrade a tremendous amount more before reaching the same level of bluntness.

This difference is so great that even a really low grade steel will outperform a much higher one if you compare rough to polished. S30V is no different in this manner, I have used Bos treated, Custom and Production (Spyderco, a few blades). Phil Wilson has used a coarse edge on his CPM blades for a long time, S90V, 10V, 15V, etc. . He runs a SiC stone usually.

Again, with respect to slicing on a draw only you want this finish. This is nothing "intuititave", Mike Swaim first described it on rec.knives long ago, Joe quantified it in some detail later on.

Now you need to be clear what is meant by draw slicing, if you are trying to slice plastic for example you would still want a high polish as you can't actually saw plastic with a coarse edge (unless the plastic is really thin like a pop bottle), and what is actually happening is a push cut.

In any case, if S30V was crumbling with a coarse edge it means the grain is blown and/or the steel is too brittle. The latter it pretty much impossible though as I have run them on really brittle steels like S10V at 62/63 HRC, and Phil has run them on even harder and higher alloy steels. Mike Swaim also had Alvin's knives at 64-66 HRC and made no mention of it either.

-Cliff