In this video I hammer out a large Bowie knife from a farrier rasp and a guard from a rail road spike.
I quenched the knife in water because that's how farrier rasps achieve proper hardness in my experience. The blade was kept thick (a little less than 3/16") and thermocycled 3 times to help avoid cracking and warping. Then it was tempered at 400 degrees for 2 hours twice. Thanks for watching!