When sourcing used lathes, you must prioritize the Swing Over Bed (maximum diameter) and Distance Between Centers (maximum length) to ensure the machine fits your workpieces. Critically inspect the spindle bore diameter and spindle speed range (RPM). For precision work, verify the bed way condition—look for hardened and ground ways with minimal wear. If purchasing a CNC lathe, confirm the controller brand (e.g., Fanuc, Siemens, or GSK) and ensure the servo motors and drives are fully functional and parts are still available in the market.