STL files for 3d printed Nema 17 rack and pinion drive

This page hosts 3d files to produce a 3d printed Nema 17 rack and pinion drive unit suitable for DIY CNC machines. I am calling this one 'mini-rp'.

There is no minimum price to download the files. 

If you like the design, buy me a coffee and help fuel my R+D process!

This version works with Accuride 2026 drawer slides, 18mm plywood for the moving carriage, with 9mm plywood used to space between the drawer slides and carriage to create space for the fixed rack. The total gap between the moving carriage and the fixed plywood panel is 18.5mm.

The following files print well with a 0.4mm nozzle using standard PLA

‘125mm_rack’: Approx 125mm of 1mm module rack with a flanged base for bonding. For larger travel I butt these sections up against each other and bond them in place, aligning them with a spare piece of rack.

‘Drive_side_faceplate’: One half of the motor mount/drive unit, where the Nema 17 motor mounts

‘non_drive_side_faceplate’: Opposing half of the drive unit with holes to allow access the Nema 17 motor mount screws

‘drive_unit_standoff’: This is a thin stand-off that glues into grooves on the faceplates to create a rigid drive unit from 3 parts

‘gt2_20_5mm_id_pulley’: A 20 tooth GT2 belt pulley to fit a standard Nema17 motor

‘gt2_61t _driven_pulley_pinion’: This is a combined 61t GT2 pulley and 1mm module pinion gear

The 3d printed parts need to be combined with non printed 'vitamins' for assembly:

2x 608z bearings

4x mounting screws to attach the drive unit to the gantry

1x 170mm GT2 6mm wide belt

1x M8 bolt to use as an axle

2x M6 bolts and hex nuts for the preload screws

1x short M3 grub screw and hex nut for attaching the pulley to the motor shaft

Plywood gantry/carriage from 18mm plywood

9mm plywood or other similar spacers

Accuride 2026 two way drawer slides and mounting screws

I’m really hopeful you have a good experience printing and testing out the design, if you have any issues let me know,

I would really like to help to modify the design to suit custom applications, please give me a shout if you have any feedback.