Something a farrier said about steel hardness clicked for me yesterday

I was at a local hammer-in near Richmond and this old farrier was talking about how he treats his shoeing rasps compared to his forging tools. He said he never lets his rasps get hot because the heat treat is really shallow on those things, like maybe 0.020 inches deep. That got me thinking about my own tongs and how I've been quenching them way too hot for years. I always just dunked them in the slack tub after shaping without thinking about the temperature. Turns out I was probably softening the steel instead of hardening it. He showed me how he heats just the very tip until it's barely non-magnetic, then oils it slow. Tried it on a busted pair of tongs last night and they're gripping way better than before. Anyone else ever had to unlearn bad heat treat habits from just assuming you knew what you were doing?

2 comments

2 Comments

dylanward1mo ago

That non-magnetic trick is the real deal. I ruined a good pair of tongs years ago by quenching them from bright orange, wondering why they kept bending on me. The shallow heat treat thing makes sense too, I never thought about how thin that hardened layer really is on files and rasps. Been using a temp stick on my tongs lately to be sure, 1400 degrees for the critical range. You can also rig up a simple magnet on a stick to test while you're at the forge, just touch it to the steel and watch when it stops pulling.

oliver_ward141mo ago

@dylanward, the magnetic point is actually a bit above critical temp, not below it. Still, good trick to watch for.