This metal shaft coupler connects a 5 mm stepper motor shaft to a steel drive rod, transferring rotation between the two components.

The coupler measures 42 mm long and 15 mm in outside diameter. Four side holes are intended to be tapped M3 for set screws that secure the motor shaft and drive rod.

Earlier plastic versions slipped during testing, so this version is intended for metal manufacturing to improve rigidity and provide durable threaded connections. Set screws can engage flats on the shafts to help resist slipping during repeated clockwise and anticlockwise turns.

The STEP file is included. Finished bore dimensions, shaft clearance, and M3 tapping requirements should be confirmed with the manufacturer before production.