Summary

You can use the Bowden Connector part to convert an existing makergear filament for Bowden use with a pneufit.

Or print the modified Filament Drive which already accepts a pneufit.

The Space is for the Ball Bearing!

Instructions

List of Materials:

2 x M4x16 S/S allen bolt cap screw
2 x M4 S/SS hex full nut
1 x M4 washer
1 x 625 ball bearing
1 NEMA-17 motor with an integrated Planetary gearbox with a 5 2/11 :1 ratio.(robot-italy.com)
1 Pneufit straight adaptor, 1/8inx4mm (reprapworld.com)
1 x spur gear #S10T05M022S0508 from SDP/SI
3 x M3x25
3 x M3 washer
4 x M4x16 (2 for Rostock Mini motor mount)
2 x M4 nuts
2 x M4 washer (for Rostock Mini motor mount)
4 x M3x16 (for motor mount)
4 x M3 nuts (for motor mount)
4 x M3 washer (for motor mount)

Make an M10 thread and carefully screw the pneufit to tighten. With a piece of filament check the alignment.
Firmware settings for filament drive is ~ 520 steps per mm when doing 16 microsteps and using 200 steps motor

Makergear Filament drive goes Bowden