About this 3D model

IMPORTANT NOTE: This will not work on a Prusa i3 or really anything that is complete and available. I think the design is pretty cool, but you'd need to build a machine around it. This is combined carriage and extruder for 70mm spaced vertical x-axis. It uses 4 lm8uu bearings and can be removed from the machine without tools or disassembly of the x-axis. With the idler open the hobbed bolt and gear can be removed and cleaned without tools. I've done an extruder test and it rides nicely on the rails, but i wont be able to print anything with it until i build the rest of the machine. X-ends available here: http://www.thingiverse.com/thing:18539