Need help mounting Nikkor 150/5.6 to Copal 0 board

[chassis]

Hi all. I've done some searching on the internet and on this site specifically, with no answers.

Today I took possession of a Toyo 45AII and 150/5.6 Nikkor W in a Copal 0. The camera came with two lensboards, one in the original packaging stating "1601 #0 Lens Board F/45A/23G". The in-box lens board looks the same as the one on the camera, so I conclude they are for a Copal 0 shutter.

Problem is, there is a small slotted screw head that protrudes from the rear face of the shutter. It prevents the shutter from sitting flush against the lensboard. The screw is not real tight, just barely snug (I can easily loosen it with a fine screwdriver).

To get the shutter to sit flush against the lens board, a notch would need to be machined in the lens board hole (doesn't seem right), the screw would have to be removed (but why is it there?), or I need a shim which I don't have.

Has anyone mounted this combination of lens + shutter + lens board? Thanks for any help and direction.

p.s. I don't think this outfit (camera, lens, shutter) has ever been used. Is the screw provided from the factory, and it is discarded if not required?

[chassis]

Looks like I found my answer. 10 minutes more searching produced this video, which tells me the screw is an "indexing screw" which is optional, and requires a notch cut into the lens board. I will not use the index screw.

http://www.youtube.com/watch?v=2JjzwjO5ZSE&feature=related

This gentleman is really a great asset. I have watched a few of his videos and it has really helped me comprehend large format photography, from a process/mechanics/workflow point of view.

[Leigh]

That's an anti-rotation screw. It requires a matching hole in the lensboard, which is actually on the edge of the mounting hole.

Its purpose is to prevent the shutter from rotating with use, loosening the retaining ring to the point that you might have light leaks or other problems.

These were standard on LF shutters for many years, but they've fallen out of favor.

The shutter will function properly without the screw. Make sure you tighten the retaining ring securely.

- Leigh

[chassis]

Thanks Leigh!