Filament Spool Holder

__2019-01-12 Revision (r1):__
This revision changes the following:
- Adds *TAB* & "Groove" features that provide positive alignment of the sides to the base,
- Reduces width of the base by 5mm to accommodate thinner spools.

The *Prusa i3 MK2S* is a great printer especially for the hobbyist or light industrial desktop user. That having been said it is a raw printer without a lot of accessories that would make it a great printer. The is the Third in a series of accessories that I designed for the *i3*. The others are:
- Enclosure
https://www.thingiverse.com/thing:2396990
- HEPA Air Scrubber
https://www.thingiverse.com/thing:2394452
- OctoPrint Print Server
https://www.thingiverse.com/thing:2401423

The filament holder supplied with the *i3* is mounted to the top printer structure and will not fit into the enclosure. Other popular spool holders likewise will not fit into the enclosure and operate satisfactorily.

This *Filament Spool Holder* is designed to sit on the to