Gear Ratio Demo

thingiverse

I've been captivated by gears since getting my first 3D printer and now I can make them. Here's a project I just completed that showcases how gear ratios function. This compact unit holds three gears, and the gear you turn determines if it demonstrates a 4:2:1 or 1:2:4 ratio. When you spin the top gear, you get a 1:2:4 ratio, meaning for every one full rotation the top(input) gear makes, the bottom(output) gear makes four full rotations. This project isn't practical for anything except demonstrating how gears can be manipulated to increase power from input to output. I've included three boxes with different tolerances: low (0.1mm), medium (0.15mm), and high (0.2mm). Two types of gears are also provided – one is just a gear, while the other has an alignment mark for accurate rotation observation. The stacked gear box isn't designed to withstand forces generated when driving the low ratio gear (the top gear if placed with the smaller gear facing upwards), so it works best when driving the high ratio gear. It can hold up to 14 gears, which is a remarkable demonstration of how little the last gear moves. Update 6/14/19: I've added a new gear and a drill chuck piece. These two components can be glued together and then used with a drill to drive the gears and observe their function in action! If you have any questions or comments, please let me know so I can improve this design.