Pex Tank Fitting

This is a tank fitting to connect a tank to 1/2" PEX pipe. It uses a size 211 O-ring (AS-568 sizes) for the seal. Just push it into the groove where it will be retained.

Drill the hole in your tank at 0.75inches (19mm).
There are three versions, a short and a long one with fine threads and a short one with coarse threads. The particular tank I was attaching it to has a lip that the wing nut would hit, so I made the extended version labeled with "long". I prefer the fine threads, but the coarse probably take less working the parts together to make them run smoothly. I have not printed the coarse version.

If anyone needs a metric version let me know. It will probably still work fine with a 20mm hole, but it would be better to go up one O-ring size. This design also doesn't let the wing nut slide over the crimp ring. If you need that I can make a bigger one. I wanted to keep the hole as smaller in this design.