This one. The one inside the top cap that this "adjustable" two-piece copper screw fits into.
I saw other people posting on ECF about the delrin slipping - and that's where I found the way to fix it using a tabletop. I think it was on the ElectroNicStix forum that I saw it.
It's supposed to slip down based on what you're screwing on to it. Example: If you use the KFL vs the Magma as JDS', the Magma will push down the delrin because it has a longer 510 connector. When you go back to the KFL, you'll have to move it back up so that the shorter KFL connector can make contact with the centre pin. I don't expect to move mine much, since I have a dedicated KFL for the ZNA. At worst, I might screw a different KFL on to it.
