Hand Tools Archive

Re: S30V at Rc58
Response To:
S30V at Rc58 ()

david weaver
I don't disagree with any of that. The floats that LN makes out of S7 are another good example of really good toughness and not chisel-like edge holding.

But what I'm whining about (and that's all it is) is that you take some of these steels and you make them 58 hardness, and then they drop their initial edge and they really don't hold that keenness. I guess that's not the point of them, but then they fail in real life cutting tasks compared to something like GECs 1095.

I saw several more reviews of Tidioute knives where people did a cut test in something like cardboard and found the 1095 to match high numbers of what they had with other knives that were alloyed. Except the profile of the tidioute knife is better for something like that (slicing), because it's thinner, and I'm sure that has something to do with being able to drive it into relative dullness - but on top of that, the initial edge is better as is most of the wear profile until it's really dull.

All of the heavily alloyed knives that I've run across just give up that initial edge, and the only steel I've seen that really keeps it is high tungsten steel (T1, perhaps or something else similar to old high speed steel - almost impossible to find and to my knowledge, not rust free). T1 will actually sharpen nicely on natural stones, but if you do a test on something really abrasive, it probably won't hang with the high chromium and high molybdenum steels (or are the V series vanadium? I'll admit I haven't looked...they must be, because something comes to mind...that in a second).

At any rate, the failing of good carbon steel blades for cutting and slicing (which is most of what we do) is two fold:
1) when they're offered, they're usually not hard enough. Ontario specs 55-58. 55 is a good hardness for a machete, but it won't hold a fine edge. I suppose if you're selling knives to people who abuse them, then that's what you do. I'm sure they have a reason, because tidioute is going 60-61, but perhaps it wouldn't tolerate a 12 year-old trying to cut a bridge cable and may fail spectacularly
2) they rust. This is actually pretty easy to keep ahead of in a knife that you look at more than once per week, but not so much for one that you might store somewhere and look at it once per year.

So, anyway, it's the resistance to sharpening stones combined with the desire to give away that initial edge that I don't like about the really wear resistant steels. AT 58 hardness, they're probably eminently sharpenable by a wide range of waterstones. At 64, they would not be. Probably the vanadium carbide steels are only easily sharpened by CBN and diamond, anyway.

But, man, all other than the friodur razor stuff seems to be really lacking. I have a henckel's chef knife that's intended to be steeled and says "ice hardened". It doesn't match their older razors in terms of quality, and i'm not sure why. And that's hardness aside - it chips a little.

The fast refresh, the tolerance to a strop and keeping that uniform initial edge is really the top of the heap. But it doesn't allow for all kinds of things that don't enter my head, like saltwater (a need claimed more often than actually needed, I'm sure), disuse, inability to sharpen, etc.

I like the softer 1095 knives about as much as the ones with big carbides. They're just missing it. Kabar stockman as a reference point - probably mid 50s hardness. George had a hard one and recommended it to me, and I bought a used one that was a bit of a basket case due to prior rust. It just wasn't hard enough to hold a good edge, and it took a tooth off of natural stones because they have an even battle with 60-62 hardness, but they cut 55 or so deeply.

Back to my story. Quite often, people send me messages on the straight razor board looking for free advice in oddball cases. One of them is a guy who's just about driving me nuts right now, because he bought a thousand dollar stone from alex gilmore (I suspect it's a fast stone that requires a specific technique to sharpen a razor) and he's trying to figure out how to use it. I sell cheap razor stones on etsy (not plugging here, this crowd isn't my target) to try to set up new shavers with a tested stone that doesn't cost four figures or even low-mid 3 figures when it really should be $75-$125, etc. I tell all of these people (with razors) to buy a well ground vintage razor, find one straight and either buy a stone like I'm selling from me or someone else. I don't even care if they buy from me. This guy has literally sent me about 125 emails asking about technique. I'm sure one of my tested stones would solve his problem, but he's reluctant because he bought a fast (and fast means more coarse in the world of natural stones) kiita bench stone. I don't want him to buy from me to make a profit, I want him to buy from me to stop sending me questions!!! Simple steel and a simple stone - rub them together and shave for a while. That leads in to this...

Another person on that site who is a moderator sent me a message. He offers to sharpen peoples razors for a fee. Someone sent him an S30V very heavy custom razor. Both of those are non starters:
* There's no virtue in really heavy razors. That equates to a large bevel and is counter to what you want in ease of sharpening. Heavy is done with custom razor makers because they don't have the skill that european cutlers worked so hard to perfect (and later, japanese cutlers trying to improve on western razors) - the double hollow with a very fine singing grind. You strop it, it rings. The heavy ones sound like rubbing a pet rock on a pair of fruit of the looms. Nothing.
* S30V apparently doesn't take an edge from anything that people use for razors.

I'm guessing this guy spent several hours screwing around trying to get something out of the S30V, and each time he stropped it, it probably gave up whatever he achieved to the linen and leather (and wasn't that good to start). I gave him a talk about the carbides and abrasives, told him to find diamond powder or solution if he'd bought some in the past, and the said he'd dig (and eventually found something). Then I told him to sharpen the razor with the finest diamond compound that he has, strop it very lightly, test shave with it and if it's OK, ship it and tell the buyer that if he likes buying $500 massive razors for display, that's OK, but they're not going to be very good shavers unless they're made of something people would've made razors from 100 years ago. I told the sharpener to skip using anything natural on it (escher hones are popular finishers with razor people, for example), and people don't necessarily like that because with razors, especially, predictable and consistent is important. But si02 and vanadium carbides, no point.

He did that, sent me a message of "phew" and then that was it. If the customer of his had bought a $30 vintage zwilling carbon steel razor, he could've shaved with it for a lifetime, rubbed it on a stone twice a year and subjected it to linen once per week and leather daily.

I feel kind of the same way about the "good" 1095 pocket knives. If you can rub it on a stone a little bit, and buff off budding corrosion, nothing else is as good. But it has to be hardened fully to be "good", and it usually isn't. thus my constant gushing about GEC, and the tidioute sub brand wall street knife (which is a lockback, and given as sharp as they get, a lock back is appreciated).

If I had a sailboat that I stored at a marina and used twice a year and just wanted to put a knife under the dash, I'd have different considerations. Just about everything else folks do with knives (splitting wood, etc), I generally have better tools for, and as many times as I've been in the woods (grew up in the woods) and made a fire, it was always a whole lot easier to start with small sticks and work to large and split nothing.

Very long winded way of saying, yes, I recognized the virtue of the carbides, but they take away the two best things on a good knife - that instant sharpening that you get with a wharncliffe lockback (for example), and the ability of the knife to hold that initial edge and fail uniformly once it does (rather than letting go of hunks).

(V11 wouldn't make a good razor steel, just a hunch. That's also going through my head as I mention these properties. Not because it doesn't sharpen finely, but it probably doesn't when you get to that level of sharpness and that acuteness of angle - but because it really holds onto its wire edge. It's not a "dry" steel - a term that's been used on here quite a bit).

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