Peter's geared extruder for Prusa i3 MK2

Extruder of Prusa's i3 MK2 can be converted to geared version with the modified idler and three extra 3D printable parts. Other parts are the original extuder's parts.
Additionally you need M8 hobbed bolt, three M8 nuts, two 608 bearings, 6-7 washers. One of the nuts should be self-locking nut. This nut will be inside of the extruder. One of the 608 bearing is just placed between extruder body and the X carriage. No nut or other fastener needed, maybe the extruder body has to be filed a bit.