Summary UPDATE, PLEASE READ: -------------------------------------------------------------------- 2/13/17- Though the concept does work, after some load testing and some backlash testing on this gearbox i realized that my decision to round off the gear teeth (intended for easy printing) was a very bad one. This gearbox has excessive backlash and the rounded teeth actually causes the gears to go crooked in the gearbox and bind it up, almost completely taking away the gear ratio advantage. I have learned from this failure and make better "things" since. https://www.thingiverse.com/thing:2054378 http://www.thingiverse.com/thing:2101218 For any instructions i have missed, please refer to the larger version, they should be helpful to you (until i can get a new video made), they are very similar except this one needs to have the planet gears arranged as shown in the picture above Heres the larger version https://www.thingiverse.com/thing:2054378 //--------------------------------------------------------------------------------------------------------- PARTS NEEDED -The 18 Tooth Ring Gear -The 19 Tooth Ring Gear -The Planet Gears, ( I printed the The Less Backlash Gears, the others are for if you have fitment issues) -The NEMA 17 Mount. You must not use both D-Shaft Sun Gears in this gearbox unless you cut your shaft shorter! -For a 50.4:1 Ratio Choose the 5 Tooth D Shaft Sun Gear and the 6 Tooth Clearance Sun Gear -For a 38.75:1 Ratio Choose the 6 Tooth D Shaft Sun Gear and the 5 Tooth Clearance Sun Gear //--------------------------------------------------------------------------------------------------------- INSTRUCTIONS FOR ASSEMBLY! There is Alignment Marks on all gears this time. Please Refer to the pictures above, (They are Small Circles, either inset, or extruded. Always Check where the Flat Spot is on the Sun gear and D-Shaft before installing it. Always Insert the gear set into the housing with the D-Shaft Sun gear facing the Motor.