Hand Tools Archive

Subject:
Re: Voids in steel
Response To:
Voids in steel ()

david weaver
I figured that (perhaps lack of rigor). I also figured that until they're an issue, I'll pretend I didn't see them because those chisels are otherwise my favorite of new chisels.

the surprise was when getting that fallknaven knife (or whatever the brand is), the hardened powder metal center also had bubbles in, but many more. They're at the edge, and you can tell because the knife snags some hairs. Realistically, it doesn't matter. It's still sharp. But something in the process wasn't going right for there to be small voids.

When I go back to the stuff that was smashed by a hammer (either the japanese chisels, which get smashed when they're laminated in a die (or in the higher end cases, maybe by hand. I don't know. Either those, or the vintage butcher stuff), no such thing appears.

It's certainly true, though, that some of those old irons are a bit soft, and they require someone to put big boy pants on and do a little more than take a million thin shavings. I don't appreciate irons like that for a dedicated smoother, and that one that I took pictures of (the butcher) is in a single iron jointer from somewhere around 1820-1840 given the maker (and the fact that it was unused when I got it - plane and iron). It doesn't fare well in a single iron plane, but it would do OK if it was double iron.

No voids, though, and perhaps someone grinding with a sandstone and using a charnley or a slate in 1820 would've appreciated that. It's not hard for a maker to make an iron like that harder, and butchers tend to have that mild softness - it must've been their market.

It takes so long to set up the microscope and take pictures (because those scopes are designed for flat surfaces, and work holding becomes a chore with various chisel lengths, etc) and post them that I'm not sure how much I'll do. I generally use it to check razor edges before selling them. Not vital, but it ensures that I get no comebacks for things that I didn't notice, and it also ensures that I identify dud razors that don't tolerate the strop. It's interesting otherwise for woodworking, but the bar for a decent edge is much lower since the bevel angle is double.

I can only speculate on why those bubbles haven't appeared in anything old yet, and never say never, I've only looked at a few things. they haven't appeared in any japanese tools that I've looked at yet, and I've looked at a few dozen, but I doubt Hitachi would allow such things out of the factory. I have rikizai coming, but those are probably rolled, too, before they're milled. I'm guessing the weld on the rikizai is a forge weld, even though Tsune's HSS rikizai is glued. If it isn't, I don't really care, as long as it doesn't separate.

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