side spool holder for prusa mendel i2

UPDATE 10/31/2014
- Now only two vertical bars are needed.
- Still aligned with the extruder movement.
- added 3 sizes of spool holders, and the source files so anybody can modify to other spool sizes.
- the old files and pictures are available also.
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Made to be as part of Prusa Mendel, using the same bars you used to build your printer and the bar_clamps from ( https://github.com/prusajr/PrusaMendel/ ).
This is inspired from de PrusaMendel design and the new parts are