a knurled ring that twists to catch the nuts on the pins. I would like to know what it is so I could get a faceplate for the 4 jaw.
I googled that number, that's it "Thanks" do you know of a company that sells themI bet you have a DIN 55027. Does it have a bayonet that you close then tighten the 4 nuts? That's the same as what I have and when I first saw it, I thought it was camlock.