Drain with 1/2in pipe threads.

thingiverse

This adapter screws onto the wall of a container to connect to 1/2-inch NPT threaded pipes directly.\nThe threads can get tight before making contact with the surface, which is why I used a spacer made with extremely thin walls in my project. You can find more about it on my blog post at https://theheadlesssourceman.wordpress.com/2016/01/02/drain-with-1-2in-pipe-threads/\nPrinter Settings\nRafts: None\n \n Supports: None\n \n Resolution: Low, with two shells for each part.\n \n Infill Density: 10 percent\nNotes to Printer Users:\nThe design should be printed upside-down, as it was meant to drain the container that contains a liquid solution.