[diydsp]

We use some where I work. They are useful in niche applications, such as our one-off research lab equipment. They wear out slowly. They work best where we have 5 different common orifices for fluid that need to be merged into one. When they wear out, we order new ones.

We pay a tech who knows CAD and a fab house rather than a machine shop. A machine shop would probably cost a lot more. Although now that we have the design down pat, we wouldn't waste as much money on prototypes.

Our design includes 2" diameter threaded ends and it holds pretty firmly although the threads do wear out and tear off the tube with vibration and heat changes.