This is a GT2 belt based reduction gear for MPCNC X and Y steppers. Standard A4988 drivers are fairly weak that might result in steppers skipping steps. Shown here 1:4 reduction virtually eliminates this issue.
The design allows to use either NEMA17 or NEMA23 steppers.
X and Y part differ only in backplate. The one for Y direction has a mount for an angled support of Z chain. Therefore one of gear_reduction_y_back_plate_f.stl needs to be printed mirrored.The main motor mount is the same. The gears are 80T and 20T. This can be changed to your liking.
The pulleys (80T and 20T) are built using this links:
The project is included for you convinience
GT2 belt (100 teeth as shown. 96 teeth would work best)
handful of M3 nuts and bolts for pulley mounting
6-32 x 1.5 - 24pcs (back plate mount)
6-32 x 3/4 - 4pc (angle mount)
6-32 nuts - 28pcs
5mm x 50mm shaft - 4pcs
Bolts/nuts to mount steppers - 16pcs
625ZZ bearings - 8pcs
The 5x50mm shaft is made from 100mm RC helicopter shaft available from multiple places. Cut it in half with a diamond cutting wheel (dremel). Add flats for easy pulley mount with M3 screws.
SKP design files are included.