Mendel90 spool holder (customizable)

Yet another Mendel90 spool holder. I designed this because I had a piece of 10mm round steel lying about and I wanted a pair of brackets in which it would snap-fit.

The snap-fit works fine and the bracket seems sturdy enough. I have noticed, though, that the back plates of the printer are quite flexible. This might be a problem: if you bend the plates outward far enough, the rod cal fall out. I don't think this will be a problem in daily operations, but I'll have to keep an eye on it.

**Update (v1.1)** (20-4-2013): made the screw holes a bit elongated, so the holes in the back plates don't have to line up perfectly.

**Update (v1.2)** (20-4-2013): improved the rod support bit, with a better and more predictable snap fit setting.