65 for 01 is too much. Randall uses 01 for his carbon steel knives and they are about RC55. Most makers who use carbon steel, 01, L6, and a few others hold the hardness to about Rc55, some even a little less.
Cyro treating has to be at least -320 F. A deep freeze won't do it. I have heard of some people using dry ice, but that is only about -120 F, still not cold enough.
01 is a carbon steel, and to the best of my knowledge, would not benefit from Cyro quenching. Stainless steels, 440C, ATS 34, 154CM, BG42, are the ones that benefit from Cyro quenching.
If you are interested in one of his knives, ask him how he knows they are Rc60 to 65, and who does his heat treating, and how it is done. Cyro treating will not harm 01, but it probably does not benefit it, either.
Rc65 is getting into the area of milling cutters and lathe tool bits made from high speed steel. If you go to Rc65 with 01, it is going to be extremely brittle. I was not even aware that 01 could be taken to Rc65, but maybe it can.
01 is a great knife steel, probably one of the best, even in the era of the super steels that are available now, but the best steel available, improperly heat treated, is just about worthless.
