| Prefix | Description | By |
|---|---|---|
 |
A differential cage using bevels | Steven Terrell |
 |
A differential cage using contrates | Steven Terrell |
This is a single print version with no supports. Some of the holes may need tidying up depending upon your printer.
The large bevel is spaced from the frame by 2 thin washers on each bolt allowing a little movement on the inner bevel. On the other sub shaft a normal washer is used to space the bevel from the frame. The short axle is held in place by the grub screw in the coupling. Position the sub axles on their small contrates such that the axles are not pressed tightly against the short axle in the coupling. Use small hexagonal nuts on the inside of the large bevel. A little tweaking should produce a reliable non binding differential that runs smoothly.
First some notes and pictures
A collar is used as a bearing. It should be "about" flush on the inside of the frame so it does not put pressure on the internal contrate - but also not too loose. Fit this before bolting the parts together.
The drive gear can be a contrate or bevel. The boss is through the frame. Also just about flush with the inside. Thin washers are used to space the gear from the frame so that pressure is not applied on the internal contrate by the boss.
The frame is made from two identical parts held together with M3 nuts and bolts. This was a bit of an experiment to improve some of the holes in the frame.
The short axle should also be put in place before bolting the frame together. It is then held by the central screw on the coupling. You may need to open out the axle hole slightly depending upon how undersized your printer makes the holes.