You often say that carbon steel is no good, but I have never seen you say why - aside from rust. Most metal heads understand that stainless steels trade toughness for corrosion resistance. What is it you've been reading that informs you that carbon steels aren't tougher than stainless, or that toughness isn't of value in knives that will see impact.
Well for one thing I value more edge-holding than outright toughness, so at least the superiority of stainless on that front should be uncontested.
As far as toughness itself goes (excepting the low-end SOG and other Chinese made stainless that is not tempered), all I can see is that among all identical designs made in
both stainless and carbon, particularly Cold Steel etc, the broken Carbon blades vastly outnumber the broken stainless blades.
For instance, even though the Trailmaster has been available in
unlaminated Aus-8 stainless by the thousands twenty years ago,
I have never heard of such an unlaminated stainless Trailmaster break, while stories of broken Carbon trailmasters are, if not common, at least very easy to find (not to mention the same for the similar Recon Scout): This is quite astonishing for knives of 5/16" stock...
It goes without saying that the laminated VG-1 core Trailmasters have no recorded failure... (And the edge holding of the Trailmaster's VG-1 is excellent in my experience, even if the convex geometry sucked)
From what I have seen of the toughness of the 440B on Randalls, there really isn't much more than can be expected of knife steel on that front...
S30V, when used in a big chopper made and heat treated correctly by RJ Martin, is simply a complete failure compared to Randall's 440B: Not just "not as good", but
a failure to the point of making the knife unsuitable for its intended purpose: The edge does a micro-wire edge within less than ten chop, something a Randall Model 12 I have will not do in a
thousand...
This despite a much thicker, "stronger" edge geometry on the S30V: 35 inclusive on 0.040", versus 20 inclusive on 0.020"...
OK so maybe the S30V is a little "tougher" than the 440B from a fracture perspective: To me a wire edge in 10 chops on Maple, vs
none in a thousand with 440B, when the thousand chops are done from a much sharper thinner edge, is a pretty drastic failure... To be fair, I have seen so called 440C from a custom ACK knife do even far worse than wire edges on Maple: Actually curling up the edge 180 degrees on Maple(!), but from equally good makers, S30V simply doesn't measure up, yet it is widely recognized as better...
In fact this S30V failure is so bad, on a 2k knife no less, that for me it places in a bad light
all the crucible steels: Maybe it is just the impact of chopping that reveals this, when more gradual wear on folders doesn't show it, but attempts to make steels better can easily make them far worse... Even 3V I know, from a very serious 1999 test with purpose-built test mules, was vastly inferior in edge holding on manila rope to 440C (as was INFI, ATS34 and a slew of others), only D-2 being anywhere close, which has been exactly my experience since... And let's not forget the Randall Model 14 in 440B that humiliated an INFI Busse Sasquatch in wear resistance while chopping cinder blocks...
I think what is happening here is a problem of perception: S30V, 3V, Carbon steels, all -apparently- take more deformation before fracturing than 440 does. The trouble is, 440 would have
resisted those same forces
without deforming
or fracturing, so the fact it can take less deformation is not at all a sign of its weakness: On the contrary, it is still the absolute top stainless for shape-stability on ball bearings, the benchmark by which all other steels are judged for shape stability...: So if you do bend it, it does look more brittle, but what is overlooked is it takes
more effort to bend it when it is real thin, compared to other steels at similar very low thicknesses...
Few people do edge deformation tests where they measure the actual forces applied to the edge. All they can do to measure the force is note how much deformation
resulted to the edge, so if the steel bends more, they think "Hey that is a lot tougher"...
Gaston