GEARED BOWDEN EXTRUDER

UPDATE: I've remixed this design to mount on a 20/20 aluminium extrusion https://www.thingiverse.com/thing:2596124

UPDATE: So I have finally got around to sorting the support structure out for this design. It is much sturdier than the previous design and the fixing holes are in a better position.

UPDATE: I had the fixing post for the idler block randomly snap mid way through a print last night. Looking at the design this was a weak point. As a result I have made the fixing post wider. Hopefully this will reduce the likelihood of this happening again.

So this is my take on a Wade's Extruder. If you look at http://reprap.org/wiki/Wade's_Geared_Extruder you will find a description of all the components.
I've made a couple of amendments to the general design such as having a hinged idler block which is put under load with a single bolt / spring. I didn't see the benefit of having four, in fact I thought it was a disadvantage. The idler pulley is held in place with a 16mm M8 cap