Every sample is a complete two-pulley drive with its belt, and each one shows off something different: splined and hex bores, keyways, captured nuts and heat-set inserts, spokes, metal or printed-in-place flanges, a tuned fit. Click one and it opens in the generator with every setting in place, ready to change. The STLs are free to download.
The 3D-printer classic done properly: a D-flat that keys onto the motor shaft, a set screw that bites into a captured nut instead of the plastic, and a 30-tooth partner held by two heat-set inserts.
Ready for an FRC robot: the bore fits REV ½" rounded hex shaft, with SH-50 retaining-ring grooves on both faces and a splined washer under each ring so nothing walks along the shaft.
Built like a machined part: ISO 773 keyways sized to 12 mm and 20 mm shafts, M5 set screws to lock them, and flanges drawn as bent metal plates instead of printed rims.
Big printed pulleys don't need to be solid: five and six spokes on a thin centre web cut plastic and print time, while the toothed rim stays full width for the belt.
Tuned for positioning rather than power: tight tooth clearance, no backlash allowance and 0.1 mm of print compensation, so the printed teeth hold the belt without slop.
Splined like a gearbox shaft: ISO 4156 involute splines in module 1, with a flat root at 30° on the small pulley and a fillet root at 37.5° on the large one.
Heavy-duty HTD 8M on splined shafts: straight-sided ISO 14 splines carry torque no set screw could, and the 36-tooth pulley is spoked around its spline hub.
One print, no glue: both flanges print in place, the top one on breakaway supports sized for a 0.4 mm nozzle, so each pulley comes off the bed finished.
For a linear axis that gets adjusted often: AT5's stiff belt, with M4 set screws running in heat-set inserts so the threads survive, and a spoked 36-tooth pulley.
More belt for more load: a 16 mm T5 belt with the face widened to suit, on D-flat shafts with an M4 set screw in each hub.
Imperial down to the hardware: an XL belt, ¼" and ⅜" shafts, and #8-32 and #10-24 set screws in captured nuts.
The ⅜" L pitch for heavier inch-sized machines: ½" and ¾" bores with ⅛" and 3/16" keyways, and a 1/4-20 set screw on the larger hub.
Small and fine-pitched: 0.08" MXL teeth on 3 mm and 4 mm shafts, held by M2 set screws in hex-shaped tapped holes.
When the presets aren't quite right for your printer: tooth clearance and backlash dialled in by hand, on the round-toothed STD S-series profile.
RPP's parabolic teeth around an open three-spoke web, with generous fillets at both ends of every spoke.
Industrial scale: an HTD 14M drive for a 40 mm belt, keyed 35 mm and 50 mm bores, a spoked 36-tooth pulley over 160 mm across, and metal-plate flanges.
Every sample is a 1 : 1.5 drive. Sprocket and gear samples arrive with those apps. Free sample files are CC BY 4.0: credit “CheapCAD Tools — cheapcadtools.com” when you share them.
