Trouble with set screws!

[BrianG]

Wait a minute: do you have a flat spot on the motor shaft? If not, you should definitely grind one first. Just use a Dremel. Just be sure to cover the motor bearing with a baggy (just poke the shaft through the baggy), or use electrical/duct tape.

NVM, I just relooked at the pic and see that it's not the motor shaft. Duh. But still, grinding a slight flat spot where the set screw goes can help a LOT.