Bowden extruder for 1.75mm filament and 1/8" push fit coupling (used for 4mm OD tubing)

This is a remix of Carl Feniak's extruder but it has the filament holes sized for 1.75mm filament and a large bore opening to accept a push fit coupling for bowden extruders.

This is the type of coupling that I used:

"4mm OD Tubing to 1/8" Male Thread - Quick Connect for Bowden Extruder Tubing"

Update: I tweaked the opening for the push fit coupling, it now screws in perfectly straight off the printer, I also tapered the filament entrance to the push fit coupling.