Problem mounting Compur #1 shutter to Cambo board

[John Hanlon]

:confused:
I'm getting back into large format work after an absence and am assembling gear bit by bit. I was attempting to mount a Symmar-S 210mm in a #1 Compur shutter to a Cambo board drilled for a #1 shutter. I find there is a small flat screw head that links the diaphragm adjustment ring to the internal mechanism that sticks out about 1 mm past the brass mounting ring. The lens mounts to the board but the diaphragm adjustment is then frozen in position. It looks like some type of spacer is required. I've not run into this mounting other shutters. It looks like I could solve it by cutting a gasket or washer. I've shown it to a friend of mine who has mounted a number of lenses and he's puzzled too. I think it's from the 1980's as it looks modern and says "lens made in West-Germany" on the side of the Compur. Thanks in advance.

John Hanlon

[Armin Seeholzer]

I find there is a small flat screw head

This is only for make the shutter not rotating on the borard and you can just take the screw out or make a small dig in the board so the screw fits in but normaly I just take the screw out its much easier!

Cheers Armin

[John Hanlon]

No, this screw is flat and connects the lever that adjusts the diaphragm to the diaphragm linkage inside the lens. It moves when you open and close the aperture. The aperture is frozen if the lens is mounted to the board. Removal of the screw would mean loss of diaphragm control.

[ic-racer]

SK Grimes may have the correct screw. The screw may be hard to come by (as the previous owner has shown you). You might have to buy a junk shutter just to get the screw.

[cowanw]

My screws, two of them, sit dead flush on the silver ring. Inside that ring, is a black ring, not loose but part of the whole, that is a shoulder for siting on the board, yielding a tiny bit of clearance for the silver aperture ring. It sits a hairsbreath higher than the aperture ring

[Jim Noel]

I think you have the wrong screw. Use an appropriately sized drill bit and drill the board deep enough to allow the shutter to sit flat.

[cowanw]

I looked again and the black ring inside the aperture ring has a screw hole for a protruding screw to fit into a notch in the lens board to prevent the lens rotating on the lens board as Armin says. Mine does not have such a screw, they tend to get removed and lost.
Is there a beveled flathead screw in this hole and has someone exchanged this one for the one on the aperture ring?

[John Hanlon]

I was about to start posting macro-photos when I found a simple solution so I thought I'd pass it along.

I stopped at an art supply house and purchased a sheet of "Creatology Fun Foam ( for ages 4 and up)". This is foam that's about 2 or 3 mm thick for kids to cut shapes out of. It comes in colors, including flat black. I also bought a circle template. I traced the outside diameter and the inside diameter with a ball point pen and cut out a sort of gasket with surgical scissors. It works perfectly! The diaphragm ring rotates clear and the lens mounts solidly.

[cowanw]

Does the rear element sit on the retaining ring or is there back thread to spare beyond the retaining ring.
When I thought of this I was going to suggest a ring to stand the aperture ring off, but I worried the lens would be pulled forward and might change the position of the rear elements.