If you are using the bearing races that are 52100 then this might be of interest C&P fro Blade Forums
52100 is one of those steels that gets a lot of discussion. It can make a great knife, but the HT for it is not simple. It can make an OK knife with simpler procedures.
I will tell you the metallurgical way to do the HT for 52100:
The steel has 1% carbon and 1.4% chromium. This means that it is hyper-eutectoid steel with a fair amount of alloy to form chromium carbides. You will have to do the HT in such a way as to allow those elements to form the proper structures. To do this you will need a HT oven or forge that can be held at a controlled temperature for ten minutes, and a quench oil that will harden the blade. The oil should be a medium speed commercial quench oil, but Canola will do if nothing else is available. Forget about motor oil and ATF, etc.
Forging - Forge 52100 HOT. It is forged between 1700°F and 2100°F, and should not be forged in the lower red colors.
Normalize ( stress relieve) - Heat to 1650°F and air cool.
Annealing is tricky for 52100. The best way without really good equipment is to do a sub-critical anneal. Heat to 1250°F and cool to black. Then quench in oil. Do this a couple times.
Cycling the steel - This is one of the Triple Treatments often mentioned with 52100. It will get the steel ready for its final hardness and produce a fine grain. Start by heating the steel to 1650°F and quench in oil. Re-heat to 1350°F and quench in oil. Heat again to 1250° and cool to black, then quench in oil. Now the steel is ready to harden.
Hardening - Heat the steel to 1500-1525°F and hold for ten minutes. Quench in oil.
Tempering - Immediately temper at 400-450°F for two hours, cool in running water, and repeat the temper.
Cryo/Sub-zero treatment - 52100 can gain from cryo if you have the ability. Do a snap temper at 300°F and them immerse in a sub-zero bath at
-100° or in LN at -325°F. (An overnight stay in the home freezer won't do anything metallurgically.) After the sub-zero/cryo bath, temper as normal.