Ok, once you have an involute gear library AND a trapezoid thread library, you can easily make the simplest of worm drives, i.e. the non-throated kind.Like all worm drives, the gear advances by one tooth for each revolution of the screw but with non-throated ones, there is only a single point of contact at any one time, and so torque and wear capabilities are limited.UPDATE: As I pointed out in the comments, AFAIK a trapezoidal profile for the worm screw is all you need to match the worm gear's involute.To make them mesh, all I did was to make sure that: This openSCAD script is a demo of the trapezoid thread library but also uses the MCAD involute gears library. It will only work if both of these are in the same directory or in your libraries directory.It is ready for animation, and I have added a GIF of the animation in the comments below.This code is in the same repository as the library: github.com/syvwlch/Thingiverse-Projects/tree/master/Threaded%20Library