I wanted to manual control the Z axis of one of my printers and also be able to view easily Z axis changes. So, as this printer had a NEMA14 motor for the Z axis I designed this small wheel to acomplish that task with a double axis NEMA14 motor (it fits also a NEMA17 axis). First designs had some holes to make it look cool and lighter. But as this part had stress from the M3 screw/nut pressing firmly the motor's axis those parts broke when I tightened the bolt. Not happy with this results I ripped out all that fancy and stayed with the bare part. This made it structurally stronger and it didn't broke at tightening any more, so this is the final design. Print it with 40% infill and at least 5 shells. ABS recommended. Doesn't require support. Uses a M3x12mm and a M3 nutlock.
UPDATE (10-AUG-2017): Added a little 20mm diameter wheel needed for a new project. This one uses regular M3 nut and doesn't have a hole for the screw head as this would reduce the part integrity.
UPDATE (14-AUG-2017):Added a cool 22mm and 32mm 'King' models, cooool!!