Originally Posted by tkamiya
About the cone... or a plate:
This is actually a multi-part assembly. (oh why...?) There is a plate or a cone. Then there is a disk that mounts in a big hole. Onto this disk, lens mounts with use of a retaining ring.
Thanks! It looks like it is just the retaining ring I need; I just ordered one from a local supplier on the Dark Lord's auction site :-)
Thanks for your response!!
Nikon 35mm, Mamiya 645 & RB67, Leica IIIb, other bits and pieces