90 ton 1/14 metal excavator scratch build w/embedded PC

[SteinHDan]

I wanted to create a very simple swing mechanism, but ended up with something not that simple. I tried various types of bearings, and I was very close to just stack 5 of these on top of each other, but it didn't roll very well:
- http://www.ebay.com/itm/262008651254
Also it would have had to be machined and the tolerance was very low.

So I ended up with two tapered bearings facing each other. It is very sturdy.

Here are the parts:



All of the milled parts are from 6mm aluminum. The slip ring is not the one I'm going to use, but the same size. There is also a slip ring mount printed in ABS (50% infill) that both hold the slip ring in position but also helps align everything before the different parts are bolted in place.

Ebay links:
- Slip ring that I will use: http://www.ebay.com/itm/141778017008
- Slip ring from picture: http://www.ebay.com/itm/371343809973
- Bearing: 30212 http://www.ebay.com/itm/160994544123

The bolts are countersunk M6 80mm and countersunk M4 50mm.
The M4 nuts are locking nuts.

First, the slip ring is mounted inside the slip ring mount:





It's important that the M6 bolts are countersunk, because they are rotating and the wires are not, and I don't want the bolt heads to catch or damage the wires when rotating.








The static part is made up of 6 rings. If I should do it again, I would make the two similar pieces above and below the bearing mount plate into just one piece each of 12mm aluminum instead of two pieces of 6mm aluminum.


















And then the previous assembly goes in from the bottom:




Underneath, the wires from the drive motor meet up with the slip ring wires: