I don't know anything about bridgeports, I just bought one and am trying to figure things out. The locked spindle may just be bad bearings or a misaligned gear. I would try to diagnose what is wrong with your "Parts Machine" before sacrificing it. If you can fix it and sell it, it will substantially increase your budget for accessories. Don't assume the motor is bad until you have checked the switch and wiring, it could be a simple fix.