This design is for Joel Telling's contest to design a spool holder for his filament racks. There are two versions of this spool holder: V1 is a siplified version that is meant to clip onto the wood planks, and hold the filament perpendicular to the shelf in order to avoid having the filament twist in it's path into the printer below. V2 is slightly more complicated in that it comes in several peices; the body is very much the same as V1 however this version allows the spindle part to snap into place on the arm. The reasoning behind this is that in order to achive the best strength and printability on the arm, you would want to print it flat on the build plate, however if this was the case, the layer lines would also be situated perpendicular to the stress from the weight of the spool, and you would risk delamination. Because of the fact that V2 comes in two pieces, you can still print the arm flat on the build plate, yet also print the spindle flat on its side, and thus achieve strength along that plane as well. Hope you enjoy this Joel! Also I am in the process of trying to return my printer right now so I have no way to actually print this out for you. :/  I did however test the clipping mechanism, and it works!