Got a 250 HP motor in with a rotor whose drive shaft was running out about .0065 at the end. It came to the shop with complaints about excessive vibration. I straightened it yesterday to .001 TIR along its length with a torch. It took heating it three times to get it there. All three spots were heated to a dull red and quenched. I've used this method a few times and have sent the things out without doing anything else. However, this particular customer is rather picky about documenting everything and may have desk jockey engineers looking at the details.
Should I spin the thing in the lathe and heat to a uniform temper of say 500 degrees F just to equalize any stresses and soften any hard spots? The shaft is a medium carbon steel, likely 1045 or similar. Would tempering likely undo my straightening job?
The factory assembly of the rotor shows significant heat bluing near where the rotor iron is installed. Now whether that is a by product of a hot lamination stack cooling on the shaft, or casting the aluminum end rings, I'm not sure. Either way, there seemed to be little concern about that level of heat on the shaft.