Hand Tools

Subject:
Re: what is your temperature measuring device

david weaver
two, but only one measures the iron itself. The first is a hanging $6 taylor thermometer. The second is an inexpensive IR thermometer, which as you're mentioning, I am assuming is a data point, but not certainly within the 15 degree range I observe with it.

The third, and most important, is the tempering color of the iron when I'm done. it should only be the very faintest straw at 400 degrees, close to nothing. I get the iron down to touchable temperature (with gloves) between harden and temper so that I can deburr the face of the iron (so that I can see it).

And, of course, the last tester of hardness is the washita.

It'd be interesting to see how close I could get three pieces of iron in hardness using my quenching and tempering process, but not interesting enough for me to find someone with a hardness tester.

The XHP iron is a bit of a cheat, though, because if I miss by 50 degrees (which would show up solidly in tempering colors, but I haven't seen it), i'm introducing additional softness of about 0.5-1 on the C scale. It is extremely forgiving. If I am pushing for hardness on an O1 iron as I did on my plane iron in this test, as well as the chisel I sent steve, I start around 360 degrees targeted and then go up by 20-25 degrees if the stone and use say "too hard".

I use a slightly modified sharpening process (in that the last stone is a slow stone and I use it in such a way that I'm pushing the failure point further into the bevel), so I can tolerate slightly higher hardness without defect vs someone sharpening with a guide or right on a hollow. If i start talking about that in detail, I'm going to have to go on coast to coast am radio.

I sent steve that chisel that I made a month or two ago, though, and sure enough, he found it a little bit hard tempered.

The same method makes japanese chisels work like a champ.

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