[Kevin Sevcik]

About hardening, I don't think the 3 times repeating will get you a lot of extra depth, but I'm going off my one class a couple years ago, same as Dr. Joe. If you're not heating it high enough to transform the metal and break your previous hardening, then your hardening isn't going to work. If you are heating it hot enough, then you're breaking down the previous hardening. I suspect what you might be doing is a poor man's version of carburizing, building up a layer of carbon from the volatilized motor oil, then letting it soak in by heating up the part again.

At any rate, some brief googling gives me a little better info for those trying the homebrew hardening. The austenizing point is apparently slightly past where the metal stops being magnetic. So heat a bit past where a magnet won't stick to it anymore. I'm also curious if the carrier can withstand a water quench if anyone has a carrier they wouldn't mind possibly warping or cracking.