I have a little die filer I've been meaning to fix up. Its fixed jaw is scarred
up, soft, and no longer holds a machine file parallel with the shaft. I had
planned to mill a jaw insert from tool steel, harden the insert, and superglue
it to the existing fixed jaw (milled away to true it up) but I don't believe
superglue will really work and I don't want to go monkeying around with
high-tech glues for a tiny job.

I figure the best way to attach a hardened jaw insert is to braze it or
silver-solder it. However, the heat of brazing or soldering would certainly play
havoc with the heat treating. The little jaw insert will only be about 1/2" by
1" by 1/8" or probably a bit thinner. What if I used air hardening steel, and
just let the brazing heat do the heat treating?

Can't quite figure out how to do this.

GWE