Shaft Coupler for NEMA 23 to 1/4" threaded rod

This is a shaft coupler that I have used in several of my designs. It couples the (1/4" or 5/16")||(7mm or 8mm) 20tpi threaded rod to a NEMA 23 stepper motor. There is an allowance for the motor shaft to use a section of rubber surgical tubing to allow for some play in the output. This is a self-aligning coupler.