Update 3 Years Later: A Shark Bite expansion joint/coupling is working great. Been using it many times a day for 3 years and no problems. Firm, rotates easily, and doesn't leak. https://photos.app.goo.gl/nfRxwakV6ib7BKwG7
I'm trying to build an exposed copper (think steampunk) kitchen faucet. Everything is easy except the ability to rotate the faucet side to side, like to reach the left sink or right sink.
See the image below. This one does not rotate left and right. How could one make it rotate (and not leak of course)?
Ordinary "swivel" fittings/couplings only swivel until they are tight. Once tight they cannot be rotated easily by hand. And if they're not tight, they leak.