2GT Belt & Pulley generator

The tooth shape follows the common GT2 2 mm profile: 1.38 mm total height, 0.75 mm teeth, 0.254 mm pitch line offset. The loop is modelled flat with the teeth facing inward, so it prints lying on the bed.

Print in TPU (95A or softer) with 0.1–0.15 mm layers and 100% infill. A printed belt has no glass or steel cords, so expect it to stretch under load.

Groove shape matches the belt profile, widened by the groove width extra so the belt seats without binding. Outer diameter is set by the tooth count: pitch Ø = teeth × 2 mm ÷ π, outer Ø = pitch Ø − 0.508 mm.

The N20 option cuts a 3 mm D-shaft hole with a 2.5 mm flat. For a press fit on PLA or PETG start with 0.05–0.1 mm clearance; print one and adjust. Add a hub for more grip on the shaft.