Bay Area Dave writes:

wouldn't they be discolored? I use to harden chisels for automotive

Not necessarily, softening starts well before coloring (depending on
the steel type, of course).

use. Worked great; heat 'em and quench 'em in oil.

But makes then brittle, you should temper them after that, there are
lots of web sites that tell you how. What do you use to heat them up?

--
Dr. Juergen Hannappel http://lisa2.physik.uni-bonn.de/~hannappe
Phone: +49 228 73 2447 FAX ... 7869
Physikalisches Institut der Uni Bonn Nussallee 12, D-53115 Bonn, Germany
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