What diameter setscrew are we dealing with? Is there enough room in the hub to tap a larger thread, like going from 1/4" to 5/16", etc.? I'd find a solid carbide drill bit the size of the major diameter of the screw, and take all the threads out. Then I'd tap the hub for the next larger thread before reassembling.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!