Planetary Gears for D&D Encounter
These are the files for an encounter I ran a few years ago. You can see more images here (https://imgur.com/gallery/q4Oxc). The intergear can be customized to whatever size hole you need, the current hole fits a 3/16" acrylic rod.
The fit may be a bit rough, since this was initially built using insulating foam cut on a CNC machine.