[George16]

Why don't you just use the carbide bits right away instead of trying the spot annealing and cobalt bits? To me, that's just a waste of my time. Work smarter not harder. Lowest speed setting on your drill press with the carbide bits work wonders when drilling hardened steel.

By the way, in order to prevent the bit from wandering initially due to the coating on the hardened steel, I sand or gring the surface to roughen it up.