40 : 1
40 : 1 · module 3, keyed
m 3 · 20° · ZA
A module 3 single-start drive on keyed 12 mm and 20 mm shafts, the wheel throated to wrap the worm.

A module 5 worm with a disc-cutter-ground (ZK) thread driving a 50-tooth wheel on a keyed 30 mm shaft.
The link opens the worm and wheel in the Worm Gear Designer's 3D view. Change the module or pitch, the starts, the wheel's teeth, the bores or hubs, then download STL or STEP.
m 3 · 20° · ZA
A module 3 single-start drive on keyed 12 mm and 20 mm shafts, the wheel throated to wrap the worm.
m_n 4 · 20° · ZI
A two-start involute worm sized in the normal system (m_n 4), on keyed 16 mm and 25 mm shafts.
m 2 · 20° · ZA
The starter drive: a single-start module 2 worm turning a 30-tooth throated wheel, 30 : 1.
m 1.5 · 20° · ZA
A printable 40 : 1 reduction on 5 mm and 8 mm D-flat shafts, with 0.1 mm print compensation on both parts.