Machine when annealed, and then harden. Rockwell C60 is getting up there. I make shear blades from D2 that gets hardened to C61 after machining, but I back it down with a temper to C55ish, according to the manufacturers instructions.
One blade of each pair is drilled and taped before hardening. The only thing I can do after hardening is chase the threads to remove scale/carbon and the final grind on the cutting edges. |