I needed a low profile mount for a NEMA 17 motor to control the focuser on a SV503 80ED but couldn't find much.
GT2 Synchronous Wheel 20&60 Teeth 5mm Bore
GT2 Belt 158mm Length
Made this and it works really well with my OnstepX controller.
I've changed over to Robert Brown's Arduino ASCOM Focuser Pro2 DIY.
I also have another mount listed for the finder scope and guide scope
and finished a full housing that holds components and cable managing.

Creality

Ender 3

No

Yes

.2

20

I print these with 6 walls, 6 tops and bottoms as well to make it fairly stout.