I've been racking my brain and up to yet all I've found are plumbing fittings.
I'm after jointing 2 tubes with a fitting i know exists but I can't find it anywhere. It pushes into the pipe, then has the equivalent female shape on the end that's jointing, then bolts through and expands like a rawl plug. Generally get them with flat pack furniture and stuff.
Best tech drawing skillz, ASSEMBLE.
The slim end push fits into the tube, then the mouth on the other end drops around the outside of the 2nd tube.Usually made of nylon or something hard wearing. So TF, what are they called?!