Latest test shown us some weaknesses in the gimbals design. The main one was that the axle was not strong enough to withstand number of forces and moments the controlling mechanism imposed.
For reference this is our “test” axle. You can see that there is not enough material in its narrowest part (at least not for our 3D printed ABS). Also the “head” doesn’t have too much surface to stick to the “fork” properly – so we actually had two event of a clean separation on that joint.
And now this is our new one. I’ve expanded the main part to get more strength (meat) there and added a conical head to get more surface for gluing to the fork. There is also a minor improvement to the lever installation shaft, but just a tiny fix there to fit better.
The gearbox cover also came with a substantial change as my main problem was that it wasn’t properly serviceable. E.g. if the level screw got loose, I would have to re-print the whole thing as the axle was already glued in the fork.
Sebi says it is an overkill, but I split that gearbox in two parts which is now properly bolted together. While it is now not obvious, this also gave me an option to print those parts vertically, which comes with much smoother result.
.. and finally – all mounted again. Looks pretty cool, doesn’t it?
Now three more to go … plus spares!