Raiscube A8R Y upgrade

Another upgrade for my Raiscube A8R, but can be useful for any RepRap, as the Y belt clamping is very poorly done out of the box. This design incorporates:

- a fixed clamp on one side

- an adjustable one on the other side

Assembly instructions:

1. Insert the belt in the adjustable piece, with the moving part fully retracted. Mount it on the H on one side - I recommend to put it on the front side, such way later adjustments are much easier.
2. After inserting the belt on its path, tighten it by hand as much as you can, then clamp it down with the fixed one on the other side of the H.
3. Tighten the adjustment screw as necessary.
4. Enjoy 3D printing :)

At the occasion of the installation, I've changed the stock LM8UU bearings to Igus (clone...) plastic ones as well. Even if it is not very well visible on the before - after pictures, but the difference is significant on print quality. The pictures show the drawers I made for [this.](https://www.thingiverse.com/make:645