This is just my process, so take anything I tell you with a grain of salt. There are some folks on here that are much, much better than I am. Anyway, I go through and get any major bends out, and work the shafts somewhat straight. After that I'll toast the whole shaft working from one end to the other, then set them aside for a few days. After they've sat for a while and reacclimated I'll go through and do the final straightening, which may take a few passes. You can quench the shafts with a wet rag after you get them straight to keep that section from bending if you're working next to it.