The few I have made, I used M2 high speed steel, and then sent them to a prefessional heat treater, requesting a hardness in the Rc 64 to 65 range.
They were heated in an, oh my, oh my, do I ever hate to used the V word. I don't know if I will recover from this tramatic expeience, but [:I][:I] they were heated in a VACUUM furnace.[:0], then quenched at 320 degrees below zero.
Since then, I have contacted a tool maker, and he recommends that M4 High Speed steel would be a better choice.
I can recommend places to get the steel, in the annealed condition, and I can also recommend some heat treating specialists. Send e-mail if you need further information.
Bonefish