Prusa I3 MK2 Frame Holder Collection: 3. Short and long spool holders

This is the third part of a little collection of frame holders for the Prusa I3 MK2 (should fit on the I3 MK1 as well). The collection will at least have the following useful holders:

1. Filament guide (http://www.thingiverse.com/thing:2053500)
2. LED light holder http://www.thingiverse.com/thing:2055511
3. Spool holder (short and long) (this part)
4. Camera mount (http://www.thingiverse.com/thing:2067731)
5. Filament sensor holder for use with OctoPi

Each of these parts has been designed by different people already and there are many versions available. The idea behind the current collection is to use existing parts where possible and design parts that follow the same design principles (same or similar angles, lengths, same way of mounting to the frame etc.). This gives a much nicer, more homogenous look of the printer.

There are many spool holders around and I have tried a few. I was not really happy since some of did not look very nice or did not work properly. One issue with some of them is over spinning, i.e. they run too easy and too much filament is rolled off the spool.

The center of the current spool holder is placed right above the frame in order to minimize the force in y-direction. It has the right balance between going smooth and not too fast.

The long version of the holder is intended for large spools (2kg) but in most cases the regular version should do.

Assembly is quite easy: print the center tube and put in one of the clips on each side. Make sure to push them in only until the second ring on the clips.