New version: https://www.thingiverse.com/thing:2866895
This remix uses a 1/8 pipe thread that can be drilled (or in the case of the e3dv6 pre drilled) to 4mm to allow a PTFE tube all the way to the drive gear.
Please comment if you have any questions.
When drilling the brass fitting put a m4 screw down the top so you don't drill through the fittings grips.
(PLA) You may want to heat up the 1/8 hole before screwing in the fitting this will make good threads and reduce the risk of cracking the part.
The V2 is stronger around the fitting but may cause interference with the idler, print at your own risk leave a comment if it works.
Confirmed, the stronger one works fine.