Mini Rzeppa constant velocity joint for fischertechnik

A working Rzeppa constant velocity joint with only 15 mm diameter and connectors for fischertechnik 4 mm clip axles (Rastachsen).

Needs six 3 mm steel balls, I got mine from aliexpress. For postprocessing you'll need a 3 mm drill, a 3 mm round file, a flat file, and a round headed Dremel file tool with ca. 5 mm.

All parts must be printed very precisely and post processed to free them from any excess filament and make them as frictionless as possible.

Print all parts as provided, with .12 layer height or less, 100% infill, use a brim if necessary.

The outer race comes in two versions. The slotted one is nice as you can see the mechanism at work and it is easier for assembly and disassembly, but the closed one is more robust and might print better.

The cage is the weakest part of the design, print it in PETG at high temperatures for maximum sturdiness. Handle it with particular care during the installation process, when you have to shift it in place to insert the balls.Never pull it from the inside of a hole, always push it from the outside, otherwise it might break between two holes. This is why the slotted outer cage is much easier for assembly.

See video for post processing and assembly.