Hand Tools Archive

Subject:
Re: Bolster and chisel definitely different

david weaver
When I heat the chisel prior to heat treat, I pretty much keep it at low red heat for a while, but non-magnetic. All I have is a can forge, which can easily be used to make a tiny thing like the bolster bright colored so that it will move easily, but the rest of the chisel never gets subjected to that. I'm afraid of carbon loss and messing up whatever was done to refine the grain in the original tool.

MAPP and the can at high heat with my torch is just enough that if I don't move the chisel, I could get flux bubbles (which I don't really want, just as the whole thing is even in color before quenching, I'll raise flux bubbles on a non-critical part to see that the rest of the chisel is close to it).

I think if I had more heat, I could get in a lot more trouble, but I really don't want more heat. It's sort of like burning meat - it's easy to want more and more heat to speed up the cooking process, but once you get careless and burn something, then you can't take that back. I can heat smaller areas of the chisel (to hammer) to a slightly higher heat, but I don't want to go too high - I see from reading that above 2100 degrees F or so, the metal will move a lot easier, but I have zero interest in doing that. Slow and steady, just a little hammering

(thinking back, I probably did heat the bolster and the tang when driving it on a little higher, but once the bolster was on the chisel, I never heated the whole thing up to bright - too afraid that it would end up bent with no way to hammer it back). I have two holes in my can forge and could double the btu's, but don't want to. The literature on carbon steel suggests that a slower heat to critical, even and slow, is better before a quench. I'm in no great rush. Only did one so far, though. The next one could turn out to be a turd with cracks in it.

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