Drybox parts for 1/4" NPT to 6mm tubing

When I bought my push connectors, I did so for pneumatics and vacuum projects, so I ended up buying a bunch of 1/4" NPT to 6mm push connectors. (http://a.co/bRYwcVv)

Turns out, it is an enormous pain to find Things with 1/4" NPT holes, and even harder to model them in freecad or F360.

This is a drybox design for these connectors, and I went all out, with semicaptive nut holders, a threaded cap that fits over the push connector for storage, and a 12mm ID hole for cramming in sponges and r