double hobbed Extruder for 3mm Filament

I converted my direct driven printer to a 3mm Bowden. But now with more friction, because of the PTFE-tube, my filament grinding increased.

so I designed this Extruder with two hobbed bolts. And the special profile of the "hobbs" in the bolt.
and my filament grinding was gone.

you need:
6 x bearing 608
1 x bearing 6000
some M4 screws
some headless M3 screws