67Carl:
The folks at Electric Motor Warehouse (via Amazon) got me a new one for a Duro Metal Products benchtop drill press I'm restoring. They're very well made and include a 5/8" to1/2" split bushing to accomodate most motors of the type you might have. Mine went on a Craftsman/Packard Electric 1750 RPM 1/2 HP motor. The pulley carries part number 4X560, $22.00, $13.00 shipping. Manufacturer is Congress Drives, Detroit, USA.
One thing to look for if you get one. I had to clean the set screw threads (9/16ths) up on the pulley a little. Also, the split in the bushing on mine was a little too narrow for the set screw to fit through to the motor shaft. I opened it up about an 1/8th with a hack saw/file and it fit like a glove. 5-10 minute job.
McMaster-Carr also has them and is great company to deal with. Hope that helps out.