I built my keezer a few years ago and didn't take any construction pictures...
But tired of unscrewing the gas line and attaching a gas ball-lock Q/D, when i needed to us the 20 lbs cylinder elsewhere, I had the idea to put a post on the 1/4" pipe I have coming through the collar.
It threads on, but really loosely. Like the threads are a different size. Fine thread and flare fittings are not right. I wrapped pipe tape around it and tightened, it doesn't leak but I'm worried that it might later on.