I fear that heating the bolt of shaft may ruin the motor as the heat
transfers to other parts. I would suggest getting a few left hand drill
bits. Yes they do make them. Try to drill the bolt out with them starting
with a small bit and increasing to a larger one as you go. Try to start in
the center. I have had great luck using a left handed bit. Most times the
bit will grab and unscrew the offending bolt for you. In cases when it does
not (this is where starting in the center sure helps) I drill to the point
where I have a very thin amount of bolt material left and use a punch to
bend the bolt inward and pull it out. Running a tap as a final step to clean
up the threads.
Good Luck
JRE