J H Dallmeyer's 3A diafragma fix problem

[menelajas]

I can pull out the diaphragm ring. Tried to screw out not working. I added the pictures form both sides maybe you have an idea how to pull it uot (gently).

I have all diaphragm leafs separately and want to bring it up into one peace.

[Steven Tribe]

I am convinced this is just a pressure fit.
I think it is like a trying to get a wheel brake drum of a car!
It is was me - I would make a wooden piece that reaches into the outermost edge that lies "flat on the barrel" - with a cut out that gives space around the gear track. Then warm the barrel a little and follow with a few taps on the wooden driver with a hammer. Repeat the warming and tapping.