I discovered this forum a few days ago, and I thought it could be the place to get some help.
(First of all, please forgive my english and my poor scketching skills)
For a little project, we will build a stacking of 3 wooden box (10x10x6 inches). one at the base that will be ground or wall mounted, and two other on the top that will have to rotate independantly.
(Their axis of rotation could not be concentric)
We have a couple of steppers that could do the job.
The thing is that we need to keep the wires hidden in the "sculpture" that is why I 'm trying to create some holow shaft rotations.
Controling the steppers is not a problem but I'm really new to mechanics.
Even if this sound to be basic things, I would need an external advice to know how to achieve this.
Here is a simple sketch. where I'm showing you my starting point.
I have heard about harmonic drive that could offer an hollow shaft but it is far to expensive for our use.
Do think I could achieve this with hardware such as pulleys, belts and strong bearings that could handle a radial weight (if this is wall mounted)
thanks for any of your advices.