When I received my very first 3D printer kit, which was a RepRapPro Huxley and became Huxy 1 (now you may got a glue of where the name of Huxy is coming from), I was very happy and amazed of various things in the pack. The most exciting was the "extruder driver" - well, I prefer to call it "filament driver", cause that it is :) A very nice piece of engineering, with tiny 623 bearings, though very compact. After assembling everything and get the first prints the problem appeared. The driver was designed to be mounted on the side of the printer, hence the filament spool would have to stay somewhere on the left of the printer, but there was no way to attach it (the spool) to the printer frame. So, I thought something has to be done and this was two fold: Differentiating characteristics: Vitamins All plastic parts print well with a 0.5 mm nozzle, and 40% infill, except for the gear, for which I would recommend 80% infill. The body should be printed with support, and you will have to work a bit to clean it. Pay attention not to cut/break the small retainers that keeps the tensioner on its sliding path! Well, if you are interested, I can make a more consistent tutorial about "how to make it" (so, please let me know), but for now that is all.