This version of Ivan, my personal robot, is a planetary gear set driven by a NEMA 17 motor.  Ivan has many incarnations - evolutions of design in which my robotics knowledge increases by doing.  Now Ivan has a team of designers at https://hackaday.io/project/7435-ivan-the-teambot all making excellent contributions and most notably - keeping me from going astray!  The gears in this version of Ivan include planetary gears made of FilaFlex with skatebard bearing centers for smooth and quiet operation.