One Piece Spool Holder - Prusa I3 MK2 / MK3 Edition

The stock spool holder for the Original Prusa I3 MK2 is a poor design. After having a spool fall off during a print, hit the bed, pop a zip tie, and causing the heat bed to just flop around beating itself to death I thought it was time to come up with a better solution. I thought I would design a simple one piece spool holder that is printed in one shot. Spool holders don't need bearings, the spool slides smoothly on the printed plastic. Besides you want to have a little static friction or your spool will unwind and tangle. I designed this spool holder to fit all of my spools of filament from small spindles to large, from wide to narrow and should fit 98% of 1K to 1.5K spools out there. Simple one handed loading allow use of the other hand to hang on to the loose end of the filament. Updated 04-28-17 - Modified the retaining groove to provide more clearance for the bearings on the print head. This is to help prevent collisions when printing above objects taller than 200mm.