This is a simple parametric model of a DIY servo motor. Model is designed in OpenScad and uses gears library: https://www.thingiverse.com/thing:1604369
Notice: unpack nonprintable.rar
more info: https://www.optolab.ftn.uns.ac.rs/index.php/education/project-base/291-simple-diy-educational-servo-motor
Demo video: https://www.youtube.com/watch?v=ObhY8etLIfg