SummaryNot created by me but by sgraber, adapted from a design by Kliment. Best way to get it is from the source: https://github.com/sgraber/i3ext But some people asked me to provide a simple printable version so here it is. You can see it working: http://www.youtube.com/watch?v=fu9SWw5dcGkInstructionsThe provided STL file contains the four pieces that make the extruder. Besides that, you will need: a piece of M5 rod, 62mm long. one nut (locking-nut is best, but a drop of super-glue worked for mine) two 625 bearings a drive gear a 608 bearing and 20mm M8 rod for the idler. a j-head hotend two 30mm M3 screws and nuts for fixing the hotend. Please note the small gear is for a shaft with a flat. It will pressure fit without needing grub screw. If your motor does not have a flat you will need to drill to size the gear bore so it becomes round.