5 mm D-Shaft To 1/2 in Hex Coupler
A rigid coupler that joins a 5 mm motor shaft (NEMA 17 D-shaft or a flatted gearmotor output) to a 1/2 in (12.7 mm) hex axle. Each side has two captured M3 nut set screws, so it works with any flat depth. It's 26 mm OD and 44 mm tall, with a 20 mm deep 12.9 mm across-flats hex socket and a 5.2 mm bore. You can drive FRC/VEXpro-style hex wheels and gears from a hobby motor without buying a metal adapter.
robotics nema17 hex-shaft shaft-coupler