This is my desing for the contest of 3dprintingnerd and matterhackers about filament spool holders.

This has to be printed in pieces, the best configuration in my opinion is this:

• 2x Carriage&Filament
• 2x CarriageOnly

And of course 4 wheels. 

Easy to assemble, only needs some force to push the wheels inside the things. All wheels spins freely with a very very low friction. No bearings needed. Since the spools can be very different one from another, i thought about this design which should fit most of them, at least all the common ones.

Carriage&Filament has also a filament guide so that Joel, which has 3 or more rows of spools, printing multiple of this or the passthrough thing only, can guide the filament from the most distant spool too. The filament guide is also pretty big so that multiple filaments can pass through it (I used the fillet on it so filament doesn't ruin).

The CarriageOnly thing has no filament guide and it should be used on the back of the spool, near the wall.

I included 2 designs which only differs for the internal width of things: one is 18mm (according to the sketch) and one is 19mm (according to what Joel said in the video), just to be sure it will fit.

All parts, except for the wheels, should be printed with supports.