I had to learn this recently to make two piston wrist pins workable for drilling and tapping. As they were no bit would even bite into the chrome like surface.
Ingredients:
Cutting torch
Construction lime
A metal container
Heavy plate to cover container
Fill the container half full of lime, heat part red hot.
Drop the red hot part into the container and cover with more lime. Top off with the plate.
Mine was still at 91*C on the top of the lime an hour later and when removed three hours later was still too hot to touch. Two hours more probably would have it cool enough to safely handle.
The once shiny surface was blackish and it drilled and tapped like mild steel. The lathe cut it cleanly also.
I had minimal materials, no truly useful instruction and orders to do it now. Somehow it worked perfectly.
