Thanks for the responses. I think a different motor with the right sized shaft is my best bet unless someone that has actually sucessfully drilled out the fan speaks up.

Pete, do you remember if the part of the fan with the set screw faces toward or away from the motor? Since it will push or pull either way by reversing the polarity I cannot tell which way it works best. The 6v motor is spinning too fast to tell since I am checking it with 12v.

Chuck