Summary

A gear which captures the hex nuts for bed levelling on the Printrbot Jr.

Instructions

V1
My printer wasn't fully calibrated at the time I made these, so I had to print them with a 10mm hex nut width to fit the 8mm hex nuts supplied with the Printrbot Jr. The (V1) .stl file has a 10mm hex nut hole that I printed, but other size hex nut gears can be exported from the SketchUp file where I have included multiple hex nut sizes which can be made by pulling the relevant faces to zero (this will be clearer when you see the file).

V2
I revisited this model after learning how to use OpenSCAD and made a parametric version. I didn't bother uploading the .scad file as it relies on an external .dxf file, rather than a math library to produce the gear shape. This version should fit the standard PBJ hex nuts nicely and should also print with a circular hole in the base rather than just a "hex lip" around the nut.

Printrbot Jr bed leveller gear