If your motor has a threaded shaft smaller than M12, which is shorter than 33 mm, you would need this Spinner-Nut. The cylindrical part goes 8 mm in the 12 mm hole of a hub. There is also a thread M4 for fixing a spinner cap.
Size: 16D
Shaft-Diameter (Hub) or
Prop-Diameter (Blade): Int. Thread 3|8-24UNF
Weight: 28.5 gramm