These are my Solar Plant Rotator project's enclosure, gears, and other parts. It is designed to hold any number of Solar Engines with their larger capacitors. I made a Miller Solar engine, but I included a version for others that might use an LED as a trigger.
I also designed the enclosure to work with a number of different available solar panel sizes I found or had available. Anything 28-35mm tall should fit. For the width, anything 20-60mm long can fit, but you will want to print an end cap of a different size. I went with a very common 30mm x 53mm.
I used PLA because I intend to use mine indoors behind glass, but if you have direct outdoor light, you might want to consider ABS or another material that will hold up.
After you have printed the box and bracket, you can create the hing by adding a #8 machine screw. Depending on your printer, you might need to screw it in to push it through.
Gears:
You should add another screw into the large gear, and this will tighten down to the hook shaft so it does not slip. On my prints, I did not need a nut, but I added a slot for a nut, in case your tightening screw slips, or you need it to get really snug.
TT motor shim:
I made a small motor shim that keeps the motor snug in the tube, but also allows you to tighten it by adding a screw if it is still loose.
Plugs:
I made a square plug that fits in the end with this:
https://www.thingiverse.com/thing:1720245
I included the ones I made.