Bent Aperture Mechanism on Copal #0

[TSSPro]

So- I think that I may have been in a hurry mounting the lens to the lens board and put the retaining ring on backwards. That disclosed right off the bat, I think that I may have inadvertently bent the ring to which the aperture indicator on the outside of the shutter is attached. I did not notice that this was an issue until I was several hours in the field without a spanner wrench, tools, or supplies. I struggled to get the retaining ring off of the shutter and replaced it with the flanged end inward facing towards the lens board. (For many of the lenses that I've used I haven't notices a flanged end on the ring. Simply the rounded end goes on top and the flat end on the lens board....so maybe I've been misinformed concerning this type of retaining ring)

Results after my attempt to loosen the retaining ring in the field: All of the mechanical functions of the lens were perfect, and only changing the aperture was a hassle. I had to loosen the lens to a degree such that it would spin in the lens board unless it was held in place by a free hand when trying to adjust the aperture. No matter how loose I try and make the retaining ring it always seems to bind in some way with the lens board unless it was not attached to the board. Has anyone run across this before?

So the crux of my post:

1: Is it possible to over tighten the retaining ring too much, or to the point where it can damage the aperture selection slider on the shutter body?

2: Is it possible to service/repair/replace this part of the shutter? Carefully bending it back?

3: Where is a reliable source for finding a Copal #0 shutter with the max aperture of f/4.5? Ebay?

 

[Dan Fromm]

Retaining rings have two faces. The front face, that is supposed to face the lens board, has a centering ridge. The rear face is rounded.

Properly bored lens boards have holes sized so that the centering ridge bears on the inside of the hole. This won't happen if the hole is too large or the board is too thin, as with 2x3 Pacemaker Graphic boards. In these cases, the ridge will bear on the back of the shutter and the shutter will rotate on the board. I think that's where you are.

The solution to your problem is fairly simple. Reverse the retaining ring, i.e., mount it on the shutter with its rounded face to the board. You might also have to put a shim between the rear of the shutter and the board.

You shouldn't have to bend anything.

A Copal #0's iris diameter is 24 mm. This is true of all standard (non-Polaroid) Copal #0 shutters.

Shutters typically have lens-specific aperture scales. If you decide to replace your Copal #0 you may be able to transfer its aperture scale to the replacement shutter. If you're lucky, you may find a used #0 with the right scale for your lens. At worst you'll have to have a new scale made for the replacement shutter. I use SKGrimes for this work.

Copal shutters are no longer made. If you have to buy one, look at dealers, e.g., Igor Camera, on eBay, and post a WTB here.

 

[TSSPro]

Dan- Thank you for the reply. I think that the shim will be the best thing for this. I need to take everything apart and re-examine everything, as well.
Is a shim like this something that is premade, or will it need to be fabricated specifically for my needs?

I have been fortunate until now to not have any issues like this with a lens or shutter in years of using them. I get one new-to-me used lens and now I feel like I'm starting over again :-( Once I got all of my older lenses mounted, I haven't changes types of lens boards, so I haven't needed to do a whole lot of switching and I feel rusty again.

Thanks again!

 

[Dan Fromm]

David, I don't think you understood what I wrote. Before you do anything silly like trying to make a shim, try attaching the lens to the board with the retaining ring reversed. That is, with the retaining ring's rounded face towards the board.

If this doesn't work, look at the back of your shutter. You should see an outer silvery disk with many cutouts. This is the aperture control ring. It is concentric with an inner black ring. This black ring the shutter's rear face and should bear on the front of the board. Hold the shutter against the board (with the retaining ring off) and check that inner black ring is larger than the hole in the board. If smaller, you're in trouble, your board isn't drilled for a #0.

If the aperture control ring turns freely when the lens isn't attached to the board and when a reversed retaining ring (rounding face touching the board) clamps the shutter securely to the board the aperture control ring won't turn freely, its time for shims. Cut a paper ring -- 20# printer paper should do -- to sit between the magic inner black ring (see above) and the board. This will space the aperture control ring away from the board. You may need several thickness of paper.

 

[TSSPro]

Dan, no matter which way the retaining ring went on the aperture control ring would bind. The resistance I've been able to see even when just the weight of the board was applied. The board is Copal #0, and the retaining ring doesn't have a rounded side, everything is at 90 deg angles, doesn't matter because both ways didn't fix the issue. I went with the shim idea, but realized that the paper shims were not getting anywhere. I ended up using very thin and narrow, ~1mm wide strip of plastic in a ring shape to work as a spacer. The aperture ring was still stiff to move off the lens, no where as smooth as other shutters, and with the plastic shim ring in place it feels as good as it does when it isn't mounted to the board.

Thank you for the input. I'm not sure if it was damaged by the previous owner. I will keep my eye out for any Copal shutters that make their way onto the 'bay in the event that the shim solution is temporary.