SFT Direct Drive Extruder

Concept for a simple adjustable direct-drive extruder.
A ball bearing is mounted onto the fourth screw hole of the NEMA17 with a slightly non-concentric lever that enables pressure adjustment.
Two M5 nuts can be inserted for Bowden-Tube Push-Fit connectors.
A 4x2mm PTFE Tube may be inserted to guide the filament path.
The extension ring for the bearing may be printed with flexible/rubber filament.
The left part has to be printed twice. ;)
An additional frame can be used as spacer between the stepper motor and the extruder and to keep all four screws in place.

First test of concept:
http://www.youtube.com/watch?v=tJi8mBMc3ug