This is a working planetary gearbox that I have designed for any use, whether that is actual use or for teaching about planetary gears and how they work. It has a half-inch output (1.5 in long) shaft and input shaft (0.125 in deep) along with a mounting bolt pattern of 2.75 in. You will need to print plates 1, 2, 3, and 4 twice and the rest once, or use the picture provided showing the number of pieces required (I found the best results when printing in object mode). To assemble there are pictures that you can follow along with, starting by inserting the 3 planet gears onto the holder and then putting the 3 pins to hold them in place, I did not need to use glue but may be needed if it is too loose. Then place the sun gear in the middle and insert the whole system into the ring gear, next place the thin ring holder on top (will not stay but just make sure you have it ready, this is what will hold the gears into place). Then if it's the first set to go into the outside shell place the input shaft into the insert on the bottom of the gear holder. Now place the whole system into the shell and make sure it reaches the bottom completely (also add the top from earlier once this step is done). Then I found it easier to insert the next ring gear into the shell, then the next step is to insert the last planet and sun set into the ring gear so it connects to the first planetary set. Then add the top for the ring gear and the 4 bolts should be able to go in, then add the input shaft to the sun gear and add the top of the shell. Lastly, screw the nuts onto the bolts to hold the shell together. There is also a crank that you can use to turn it. I hope everyone enjoys the model and to have fun with it!