27 to 1 herringbone gearset to 11 tooth pinon gear coupler
thingiverse
To construct a coupler, I utilized the gear4a import feature in OpenSCAD from Thingiverse's http://www.thingiverse.com/thing:9460. An 11-tooth pinion gear fits into this coupler. For the gear, I chose http://banebots.com/pc/P60P-GEAR/P6623M5023, although I initially intended to get the 3.2mm bore version. Drilling it out was straightforward, and I also tapped a 3mm set screw hole. This gear can be driven by an RS550 motor; I even tested it with a hand drill. Video of its operation at 1/8 speed can be found on http://www.youtube.com/watch?v=9TFWST00E_8. Printing settings similar to those used for other gears should work fine. You can download the gear4a.stl from the parent thing as well. However, note that it's parametric but incompatible with Customizer due to its requirement of an external STL file.
With this file you will be able to print 27 to 1 herringbone gearset to 11 tooth pinon gear coupler with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on 27 to 1 herringbone gearset to 11 tooth pinon gear coupler.