This is a simple solution for a drybox filament feeder using the PC4-M6 bowden tube coupler.
For assembly only a single 8mm hole is needed in your drybox for the filament feeder to pass through. Assembly of these parts does not requires tools as the knurling provides plenty of grip to tighten the parts by hand.
In my drybox setup I've used PC4-M6 couplers that allow the 4mm OD PTFE tube to pass straight through to put the end of the PTFE tube right up to the filament spool.
The basic feed through consists of 2 parts: The 01 Threaded part which contains M6 thread to attach the PC4-M6 coupler into. This part goes inside the drybox. The 02 Hex part has a slot to push in the PC4-M6 coupler.
A third optional part is included for those that want to cap off any unused feeding holes. The 03 Cover part slides over the securing ring of the coupler for a snug fit. This will not make the box air tight, but significantly limits airflow and provides an overall clean aesthetic. The final image in the list shows how the cover can be slid over the PC4-M6 coupler.
All parts can be printed in the provided orientation without supports. Should you want to print the cover part it is advicedd to have your briding settings tuned in well. Otherwise there may not be enough clearing between the coupler and the top inside of the cap.