The file '3D Printed RC Truck Rear Axle – Steel Rod Version 3D Printer Model' is (zip,stl) file type, size is 2.7MB.
UPDATE (11-august-2016) : DO NOT PRINT this thing, a much better version is now online. You can find it here - http://www.thingiverse.com/thing:1715175 .
This is a remix of the great work of MrCrankyface (http://www.thingiverse.com/MrCrankyface/about).
I wanted a more solid rear shaft, so I decided to use a 10 mm smooth steel rod (the one you use for 3D printers) instead of the 3D printed shaft.
I used a grinder to create chamfers on the steel rods, both in the ends and in the center area. The large gear has two M3 nuts on the inside, which allows the m3 screws to fix it on the rod. Same for the wheel hex, both sides.
To prevent the wheel hex to delamite for really large truck loads, I used some textile thread (black color, the cheap one you use to sew your pants), lot of layers, and some cyanoacrylate on top of the thread. You get an unbreakable material :)
I have also modified a bit the large gear so that the teeth are now connected to the center . This way the teeth are lot more strong as they are supported in one side.
You are welcome to make it better, in the zip archive you have all the Openscad source code.
Here are some tests (powered by a Proxxon at 5000 RPM) :
https://www.youtube.com/watch?v=tXvomSdxGBo
10mm-steel-rod.zip | 2.3MB | |
Axle_rear_pinion_shaf1.stl | 40.3KB | |
Axle_rear_pinion_shaft2.stl | 41.4KB | |
gear-diff.stl | 3.8MB | |
wheel-hex.stl | 88.9KB |