I guess I'm really just paranoid about ruining the crank. There was enough material for the threads to cut, I'm just worried about the material being weakened from what had been done to it in the past. I know heating can demagnetize a magnet, I was just going to heat the inside of the flywheel where it rides on the crankshaft, as far from the magnet as possible, with minimal heat to keep from damaging the magnet. I wasn't planning to heat any more than 150°,just enough to help it slide on a little easier