Good morning, Trond;

Ic-Racer mentioned the Durst People and their lens systems. Back in the 1960's they had a sheet metal clamp that went around the aperture control ring of a 50mm lens (Schneider Componon-S 50mm f:4.0) and it had a long tab that hung down from one side. The lens was screwed into a recessed lens board (the IXOTUB for the Durst 606) and the lens was adjusted using this little lever or tab that hung down from the lens inside the recessed lens board. I cannot remember the name or the Durst nomenclature for this accessory.

It should be possible to make something like this out of sheet metal, brass or perhaps mild steel, and a small screw and nut.