Copal 3 lens board question

[robertraymer]

So I have been looking for a Cambo lens board for a copal 3 lens, and cant seem to find one. I do however find a number of combo boards drills with 62mm holes. What shutter would need a 62mm hole? A Copal 3 should be 65 and a copal 2 should be roughly 42mm correct?

Also, how difficullt would it be to file out a 62mm metal board the extra 3mm to fit the copal 3 lens. I have done it with wood boards, but never with metal boards. If I cant find a copal 3 board Im tempted to try filing down a 62mm board, but don't want to ruin it.

[Corran]

Are you sure? No 62mm holes indicated here: https://www.largeformatphotography.info/lensboard_hole_sizes.html

3mm is too much to try to file out, unless you have a lot of time.

Also, what about this?
https://www.ebay.com/itm/Cambo-copal-3-6-lens-board/254556867496

[BrianShaw]

A few years ago I had similar problem. Camera repair shop machines the opening to correct size and mounted the lens. I paid about $35... one of the better investments I’ve ever made.

[DMS206]

62mm would work correctly with a thin metal lens board such as cambo. 65mm would work better with a thick wooden board where the retaining nut would go through the board, being held on by the flange. I just measured one,
Dave

[Bob Salomon]

A few years ago I had similar problem. Camera repair shop machines the opening to correct size and mounted the lens. I paid about $35... one of the better investments I’ve ever made.

+1

[Greg]

Hand filing 3mm to make the hole larger... in the past have done it many times. A good vice, a half rounded coarse file, and music in the background are all you need. I cover the front of the board with white masking tape and mark the opening I'm after with a thin Sharpie. When I was a student at RIT didn't have a vice and it was a pain to do even with wooden boards.

[robertraymer]

Thanks all.

I ended up finding a seller on eBay that had one, and who may even be able to drill out a hole for a barrel lens I like to use in the future. The one linked in the first reply was not the correct board.

Still, I am confused as to the sizing. I know that a Copal 3 is 65mm and still do not know what a 62mm hole would be for, but it seems like it is being suggested that you need a 65mm hole in a wood board but not a metal board? How is that so?

[DMS206]

Thanks all.

I ended up finding a seller on eBay that had one, and who may even be able to drill out a hole for a barrel lens I like to use in the future. The one linked in the first reply was not the correct board.

Still, I am confused as to the sizing. I know that a Copal 3 is 65mm and still do not know what a 62mm hole would be for, but it seems like it is being suggested that you need a 65mm hole in a wood board but not a metal board? How is that so?

[DMS206]

The thread diameter on the shutter is 61.8mm. On mine the retaining ring is 65mm outside dimension, with a step to a larger diameter, and it is 9.5mm thick, which is thicker than your lens board, so if you had a 65mm hole, it would not tighten, and could spin freely.202398

[Corran]

You are missing the ring so that you can have the lens spaced above the board, which is needed on some cameras.

[robertraymer]

The thread diameter on the shutter is 61.8mm. On mine the retaining ring is 65mm outside dimension, with a step to a larger diameter, and it is 9.5mm thick, which is thicker than your lens board, so if you had a 65mm hole, it would not tighten, and could spin freely.202398

I currently have it mounted on a wood B&J board with a 65mm opening that it fits perfectly in, but will be moving it to a cambo board to use with a Legend 8x10 I just purchased. The outside diameter of the retaining ring and the inside diameter of the spacer are both 65mm. The outside diameter of the shutter is just shy of 62mm (I'm guessing your 61.8 measurement. So if I am understanding correctly, if you use a thick wooden board or a thin board and spacer, it requires a 65mm opening, with the retaining ring screwed all the way in and securing the board or the spacer/board, but if you have a thin board with a 62mm opening it will still work by securing the board between the shutter body and bottom of the retaining ring, but the ring will just not screw all the way down.

[DMS206]

I currently have it mounted on a wood B&J board with a 65mm opening that it fits perfectly in, but will be moving it to a cambo board to use with a Legend 8x10 I just purchased. The outside diameter of the retaining ring and the inside diameter of the spacer are both 65mm. The outside diameter of the shutter is just shy of 62mm (I'm guessing your 61.8 measurement. So if I am understanding correctly, if you use a thick wooden board or a thin board and spacer, it requires a 65mm opening, with the retaining ring screwed all the way in and securing the board or the spacer/board, but if you have a thin board with a 62mm opening it will still work by securing the board between the shutter body and bottom of the retaining ring, but the ring will just not screw all the way down.
Yes , that is correct, I probably didn’t explain it very clearly.
Dave