Spool holder with detachable rod - for Prusa i3 Mk2/S

A very easy to print spool holder for the Prusa i3 Mk2/S. Requires a minimal amount of filament to print and is very strong. The spool holder mounts on top of the frame. The rod detaches to make switching filament spools very easy and quick. The 90 mm rod should fit most spools but I've also included 60 and 150 mm versions of the rod.

I used a more complicated spool holder with ball bearings at first but the lack of friction actually turned out to be a problem and created a tangle which ruin