As already mentioned here I had printed Geared extruder v.2 by RomanST. This design has been updated in the meantime (http://www.thingiverse.com/thing:1039445), but I already had the old version printed and lacked the time to get the rest of the BOM together (ball bearings, long M5 screws, …) and mounted properly.
The upgrade concerns the spring tensioner and it indeed was a real pita for me to get it mounted with a „decently strong“ (and by that I mean „brutal“) spring.
Dismounted „stock“ Sumpod feeder mechanism:
As I had a Mk7 gear (instead of a Mk8) I had to bend the lever for some extra clearance (after heating it with hot air):
As the Mk7 was too large in diameter I also had to shape a „funnel“ via soldering iron to guide the filament out properly.
After a first quick test went fine I
glued screwed in the pneumatic connector. A drill bit helped keeping it straight.
[Edit:] Hotmelt did not work here. But the old connector from the Sumpod extruder had the right thread to fit the printed frame. [/Edit]
Afterwards the extruder was mounted. (One bolt is enough for now.)
Calibration was easy as Roman already provided the new gear transmission ratio. Even the first print was usable!
Here is a short video of it in action (SRY for it being portrait orientation, but that will have to do for now):