This is my first upload and also my first 3d modeling attempt.
It is basically a bolt and nut couple with a small gasket. The bolt has a conical hole in the middle and is designed to perfectly fit standard 4mm PTFE tube (for 1.75mm filament).
You will need a 16mm hole (it will fit the same hole used for thing number 1233934)
I used flexible filament for the gasket.
Note: A short piece of PTFE tube is recommended inside the bolt so to reduce the drag.
Note2: you can find here a samla spool holder : https://www.thingiverse.com/thing:2399361
and a silica gel tray : https://www.thingiverse.com/thing:2236037