Until about 10 years ago, I used to send my inline 6 cyl race cranks to Industrial Metal Heat Treating in Newark NJ for Tufftriding, a type ofnitriding process. I think the process was licensed from the Kolene company. The cranks were finish ground before treatment and only required a light polish and straigtening before use. Usually they were not out by more than about 0.006" and I used the hammer peen method to get them straight within a couple of tenths. These cranks are about 30" long, weight about 80 lbs and are fairy stout with 3" mains and 2 3/4" rods, but are a somewhat soft steel. Additionally, the tuftride process put the surface of the metal in compression, increasing the fatigue life. I think the EPA made things too difficult for this process to be economical, as I am no longer able to find anyone that runs it. I have since tried Ion nitriding, but wound up with two cranks bowed more than 0.020 that I could not straighten with hammer peen. I don't want to use a press to straighten the cranks post treatment as I think it would weaken the cranks from a fatigue standpoint. Anyone have any experiance with a good, fairly low temperature surface hardening process, that would also help fatigue life and not bow a long item like a crank?