I wanted a planetary gearset to use as a demo device when teaching others how planetaries work. There are a couple of other demo type planetaries on MakerWorld, but they require gluing, which means you can't disassemble it. I feel like being able to take something apart and put it back together really helps understand how the different parts work together. So, I designed this one that uses no glue and can be disassembled and reassembled by hand.