Being a NEMA 48 frame motor, it most likely has a 1/2" shaft. Generally they don't have a key way, but a flat instead. Setscrew in pulley has to bear upon flat. Can you turn pulley by hand with shaft turning also? If so shaft isn't frozen in place. Without pulley, does motor run? Did you try to turn quill by hand without motor attached? Could be a frozen bearing in quill