3D printed NPT Industrial to tube couplings


Various fittings to convert 1/4″ NPT Industrial Quick-Disconnect to low-pressure tubes 5/16″ and 3/16″. Both male and female tube fittings are provided.

Designed based on official mil-spec MIL-C-4109F and ANSI standard B1.20.1.

Shown with Tygon 5/16″ fuel tube (yellow) and 3/16″ aquarium “airline” tubing.

I use these to feed air for various low-pressure applications like PCB etching blubbers, laser nozzles, CNC chip clearing, etc.

Threaded fittings need some sort of sealant like Teflon tape if you want them to be 100% air-tight but generally it doesn’t matter since it’s low pressure.

I print them vertically with the largest surface on the build plate.


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