I have a 90/6.8 Grandagon-N in Copal 0 that I would like to move from one lens board to another. I can unscrew the front and rear cells from the shutter but I can't figure out how to get the shutter off the board.

On the rear, there is a flange/sleeve (into which the rear cells screw) that goes through the lensboard and clearly screws into the shutter and there is a lockring on there that grips the lensboard against the shutter. I can undo the lockring with my lens spanner, but the sleeve is a T shape, i.e. I can't unscrew the lockring more than about 2mm before it reaches the top/outer part of this sleeve. So all I end up with is a loose shutter.

I've tried unscrewing this sleeve thing but it seems damn tight. Is there something I'm missing that will release it?



Outermost bit is the offending sleeve, thing with notches is the lockring that I can unscrew. Clearly I can't unscrew it off entirely, and the sleeve won't pass through the lens board.