This fitting replaces the exit fittings that come with the repbox to add PC4-M10 pneumatic couplings to connect PTFE tubes directly to the repbox.

This is a remix that compared to the original:

• extends the passthrough at the top to fix a problem wih the screw thread hanging in thin air
• adds a cone to the inner exit of the passthrough to ease feeding filament
• adds more solid body to have less dominant fingers on the outside of the passthrough
• adds a second version for direct tube passthrough

The nut and cap are the parts from the original of the remix and are just provided here for completeness. They have not been altered. The second nut of the original provides no benefit and hence was left out.

There are two screw models:

• Repbox_Passthrough_PC4-M10_v2 is the remix for the PC4-M10 coupling (screw in coupling on one side, feed in filament from the other). 
• Repbox_Passthrough_tube_v2 is meant for direct PTFE passthrough

I'm using the fitting with a Repbox 2.3.1, it is a tight fit and requires to use pliers (the passthrough then pulls itself in when tightening into the nut). I have used PETG, your mileage may vary (PLA might break on that box version because it requires some force). You can scale the model down a tiny bit for a better fit. They can be added to the front or bottom. I'm using two boxes above each other and pass tubes from the upper through the lower (on the lower box I use the passthrough tube screws so that the tube runs straight from the upper box to the printer, for the front fitting and lower back fittings of the upper box I use the PC4-M10 model). The second extended cap enables to pass through a PTFE tube (screw in the fitting from out to inside, then use the cap with tube hole inside for better protection against humidity, you could also use another PC4-M10 coupling on the outside as an alternative).

Print Instructions

Material and infill are chosen because the passthrough requires some force to mount (but I had no trouble on any of the nuts). You could also try to scale everything a bit, it eases the fit into the Repbox (scaling too small will cause problems with the PC4-M10 coupling, may need some experimentation).

To print multiple screws I can recommend taking a look at sequential printing. Make sure to sort all instances manually (the supplied gcode file does that, take a look with the gcode viewer). This print needs monitoring, I had instances where a passthrough got loose during printing and I had to manually abort the print.