RE: Please help! Can't get shaft out of a BP-12
The nut is not holding the shaft. It's holding the part that holds the shaft. You do not need to get the nut off.
As I said before, the shaft is pressed in. It only needs to move a short distance before it will fall out. You should be able to tap it out with a hammer, but the motor bell has to be resting on a solid surface.
I would get the shaft partially straight, then drill a hole through a block of wood just bigger than the shaft. Drop the front end of the shaft into the hole so the nut is resting on the block, then tap the shaft out with a hammer.
Sometimes you can get lucky and straighten the shaft by eye, but most people don't have that good of an eye. Any noticeable wobble will rob power and ruin the motor in a short time. Replace the shaft.