Originally Posted by
HimyKabibble
If you want to attach a pulley to the gear, bore the pulley to several thou under the OD of the gear end, then cool the gear and heat the pulley. They'll slip together easily, and be locked together for life. I'd recommend putting a lip on gear, to make sure the pulley seats square to the axis of the spindle. If you want some insurance, after it's assembled, drill an axial hole at the gear/pulley interface, and put a dowel or roll pin in it, to act as a key. It'll never move on you.
Regards,
Ray L.