I have one of those Craftsman saws, as did my father before me. The weak spot on them - in my limited sample of 2 - is the arbor pulley. They tend to loosen with use, and if you let them get too loose, the pulley will spin on the arbor and the setscrew will dig a trench all the way around it. There may be a Woodruff key; even it can be damaged by a loose setscrew. Check for tightness, and listen for a clicking sound as the blade spins. Retighten often!
On mine, the arbor shaft was in such bad shape I had to get an oversized Woodruff key and carefully machine out a pocket for it with a Rotozip with diamond cutoff wheels.(my Bridgeport was at the cleaners') Tedious, but worked. It still loosens, but has sustained no further damage.
Oddly, the motor pulleys stay put with no trouble.
I picked up my saw at an estate sale with the Craftsman roller stand with front mounted switch, both extension tables (the stamped steel ones

), dado knives and several blades for $25 - and that was the asking price!