Hand Tools

Response To:
The chase ()

David Weaver
...the V11 chisels are a low toughness high strength edge, much like japanese chisels.

The chisels that fare the best in tests are higher in strength than toughness, but beginners may complain about edges chipping or snapping edges off when they start using chisels as a lever.

Yes on the geometry - heat treat and geometry dominate, as does skill in use. A pure user of tools with no interest in the tools should care little about any of this.

But they're really excited about furniture, and they go way beyond making something just good enough to store socks. They want the furniture to store socks and have all kinds of other non-practical qualities.

People who make tools tend to do the same things with tools - I don't love 1095 for chisels because it seems to have edge chipping issues, but it can be made to work well (the 1095 chisels that I made but don't like that much are definitely better than sorby as delivered).

The other issue here is that we're always hearing about edge toughness, but people complain about deflecting or rolling edges. When I modify hardness to eliminate chipping, it's not a matter of searching for a tougher steel, it's getting the heat treat right. many of the very tough steels do poorly with fine edge holding, but they are tough in the sense that you can lay a knife edge on something and mallet the back of the knife and get only fine edge issues.

I suspect files are fairly low toughness, but they are a steel alloy that is very high strength at high hardness. If they are tempered softer, then their value is lost (they may take a very crisp edge and feel very good, but at 61 hardness, the very high carbon steels aren't doing anything that 1% carbon doesn't do well, and at 58 hardness, 1% steel isn't doing anything that .8% steel wouldn't do well, and the lower carbon steels at a lower hardness will be tougher.).

One puzzler for me at this point is that AEB-L will challenge 3V for toughness, but the ingot bits I've hardened don't have the fine edge holding. What I don't know is whether that's because there's not enough carbon in it, I'm coming up short (which is likely, but whether or not that's the differentiator, I don't know), or what else - it's really tough, but maybe it doesn't quite have the properties to match something like file steel. I'd have to pay peters to do a cryo cycle with a blade and leave it tempered hard to find out.

too on the 3V and A2 - both are high toughness. A2 has better toughness than O1, but its fine edge holding is worse. I'd bet its strength is no better than O1, but its toughness is better than O1 by quite a bit. It's just not the toughness that we want, even though the average person thinks that's the right word.

I can't make sense of these charts that well, either - O1 and 1095 have similar toughness numbers. O1 at same hardness after temper definitely does better with fine edge holding, but some adjustment to geometry would compensate for 1095. In a knife, that may not be a big deal. In a chisel, it's annoying because you can feel the difference. A great deal of the knife community loves a 58 hardness knife because they're hoping to avoid toughness issues (wanting to swing knives or hit them with mallets to split wood, etc) - some of the steels that seem like they would be good for woodworking, when I've read closer, the actual comparisons one next to the other find them (like 0.8Crv2) to be lacking in fine edge holding.

long story short, chipping problems that I find are often due to poor quality or undertempering. rolling are due to poor quality (or steel choice) or underhardness. I don't think we really have a significant need for toughness as it's tested given that the chisels that often dominate tests (and last the longest in my hands) are very low on toughness and high on hardness.

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