Is it a direct drive saw with the blade attached to the motor shaft or is it belt driven? If direct drive, you'll likely need a new motor and unless it is a pretty high-end direct drive saw, the replacement motor will likely be 75% of the cost of the entire saw. I doubt you could retap the threads on the shaft to clean them up. You'd need to find the proper size left-hand thread tap and hope the shaft isn't too messed up.
I had a low-end Delta table saw with an internal belt drive. I needed a replacement motor and the only ones I found online were for a generation newer than mine, and the cost was something like $250. I didn't want to take the chance ordering a new motor only to find out the mounting design changed between generations. The online reviews of the saw indicated that the motor was a weak part of the saw. It was essentially a throw away saw. So I gave it away to a guy who was willing to tinker with it. The other option was metal recycling. I had picked it up used for $100 from a widow friend of the family when her husband died, so I got my money's worth out of it.
