19 years ago
I recently made a blade for a spokeshave out of O-1 steel. I hardened
it and tempered to strawyellow (about 450 degrees) in a conventional
oven. This blade is extremely tough to sharpen because it is so hard.
It takes a lot of work just to raise a burr. Should I re-temper to
some other color?
Also, this is the second time I have hardened and temperd the blade.
On the first attempt, I left the oven on 450 degrees for about two
hours and upon taking the blade out, it was unevenly colored brownish
yellow, with some spots being blue. I rehardened and tempered again
using a thermocouple so I could monitor the temperature of the oven (I
think my oven is miscalibrated).