Bowden Extruder v2

I needed to lighten my default extruder head (I have Reprap Mendel Prusa from FolgerTech), therefore I splitted it in two: a bowden extruder on a side and a JHead (http://www.thingiverse.com/thing:1436575) on the other.

Of course I looked on existing extruders and I didn't found a full satisfying model.
As usual I decided to make my own.
I got inspiration from two things:
- The first : http://www.thingiverse.com/thing:73082 for the main structure with the step motor adjustment and the visibility to filament on an efficient driving bolt (you have to made one from cylinder head bolt. MoonCactus described it).
- The second : http://www.thingiverse.com/thing:53690 for the great idea of a vibration absorber.

I printed an existing gear set from : http://www.thingiverse.com/thing:97377
Then I found a traction spring in my workshop storage, I though that it should be usefull and make access to filament easier.

I designed the BowdenExtruder with OpenSCAD in case of change of screw