After some careful hi-spotting and filing of the bunged-up end of the motor shaft, the pulley now slides onto the motor shaft properly, so I put it all back together, this time with the setscrews tight. The wobble is now gone, so I lucked out -- things were not too badly chewed up, and no locktite will be required. Nor is the famous plastic bushing a problem.
Now, I'm trying to bleed the air out of the hydraulic system that communicated speed changes from the varispeed control on the top of the lathe to the adjustable pulley on the motor shaft. The instructions in the manual do not appear to be working.
Joe Gwinn