Hand Tools

Subject:
tempering question..

David Weaver
..isn't worth discussing - notice my previous comment about the notch test.

it's more worthwhile to state flatly that if you had 3V at 60 and you could have it at 63 with half the toughness and more edge strength, you'd prefer it at the latter in most cases.

As to two steels at 62 hardness, if one had a notch test toughness of 40 (3V and 52100 are probably two steels very similar at same hardness -both are around 40 ft lbs around 60 or just below and still over 20 into much higher hardness ranges), I'd take the steel with lower toughness for woodworking and higher toughness for an all purpose knife.

What I found with 52100 against something else similar hardness is that as soon as a little bit of damage starts to occur, the chisel won't let go of the foil that's starting to form. Damage follows after that more quickly. The amount of "unicorn" needed to stop this is far more than it is for a lower toughness chisel.

I don't know for sure that the toughness is the problem (creating a blunt foil and then allowing further problems because of it, and when compared side by side, the tougher chisel creates more resistance through wood by a lot), but I suspect it is.

It's not something I would've guessed at first, and since some makes of 52100 have 1.1% carbon *and* it's really high toughness and can go to very high hardness if you want, I thought it would be my ideal chisel steel. It isn't. 26c3 is low toughness, very high potential hardness, and even in snapping samples, it's far more brittle untempered than O!, which itself is miles more brittle untempered than 52100 (it can be hard to break a 1/4x3/8 sample of untempered 52100 in a vise. The other two just snap off. 26c3 gets to a higher hardness out of the quench, which may explain why it's so brittle untempered, but you can just give it a moderate whack - which I did today to break samples to send to larrin, and it didn't just break off above the jaws - the portion hanging below the jaws also broke. I've never had that happen before.

It's also the only steel I've ever used where I've been able to match a ward chisel in a side by side same test. 52100 is not remotely close.

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