Hi Dick.
Just a small suggestion. I remember having a similar problem. I
loosened up the set screws on a large pulley and no go. So my solution
was to get a large pulley puller. Oh man it was tough going getting it
of the shaft. When I finally got it off the shaft had two furrows in it.
Somebody way back must have had a loosening problem and put in backup
setscrews over the original ones. I had one of those forehead slapping
moments. I now remove the sets all the way and look at whats in the
hole. Take a look.

Peace and good luck.

Phredd