Hello Chris. The joint is 5/16X18 and I tried using a magnet to see if it would stick to the ferrule like other Palmers I have had, but it didn't, so I believe they are glued on. I haven't seen Palmers with this style ringwork, but Randyg says he has Palmers with this ringwork so i guess they do exist. I appreciate all the responses I have gotten so far.