dumpsterCNC Threaded Couplers Advantages:  ◊ Connect your stepper motor to the lead screw without needing a lathe to turn down the lead screw shaft.  ◊ A flat on the shaft is not needed.  ◊ These couplers will not damage the shaft.  ◊ Made from high tensile strength Delrin.  ◊ Complete with 4 stainless steel #4-40 screws and brass inserts.  ◊ Tighten the screws about 1 turn past snug. Do not over tighten, a little torque will clamp these on really tight. For best results, re-tighten after a couple hours of use.