Aperture stop pin on Copal 3

[ericantonio]

Hiya
Got a really nice lensboard today from a guy who custom makes them on ebay. Color closely matches my Korona. It was PERFECT size copal #3 however, I have an aperture pin on the shutter that sticks into the board. I unscrewed it to get the lens nice an flat on the board. Is this okay? There is a spacer of some sort on the rear thread but only works on the back of the board, not the front. Is this the way the whole copal #3 thing works? The spacer in the back of the lensboard?

[Mark Stahlke]

The spacer should fit between the back of the shutter and the front of the lens board. It provides clearance for the aperture stop pin.

Can you explain why it doesn't work on the front of the board?

[ericantonio]

The spacer should fit between the back of the shutter and the front of the lens board. It provides clearance for the aperture stop pin.

Can you explain why it doesn't work on the front of the board?
If I put the spacer in front of the lensboard, then the ring will not screw into the barrel. In other words, there aren't enough threads for it to go through. It is recessed though. Perhaps its too thick?

[ericantonio]

If I put the spacer in front of the lensboard, then the ring will not screw into the barrel. In other words, there aren't enough threads for it to go through. It is recessed though. Perhaps its too thick?

Let me rephrase that. The threaded part does go inside the hole, but the retaining ring (which slips in like a collar) hits the board, it is slightly larger than the hole.

[Ole Tjugen]

Seems to me your hole is too small...

[Mark Stahlke]

I'm still not quite clear on what's happening here. Is the spacer too thick or is the hole in the board to small for the retaining ring?

I once had trouble with a spacer that was too thin. When I screwed in the retaining ring all the way the lens was still loose on the board. I assumed the thin spacer was intended for use with thicker wooden lens boards.

On the other hand, if it works without the aperture stop pin I don't know of any reason you can't use it that way. But then I don't know everything so don't take my word for it.

[ericantonio]

On the other hand, if it works without the aperture stop pin I don't know of any reason you can't use it that way. But then I don't know everything so don't take my word for it.
I used to work in still life studios and the shutters, if working were about 2 or 3 stops more on the open end and 2 or 3 stops more on the small end. I'm thinking that those lenses were probably hacked into the lensboards as well.

Its working for now, one of these days, I'll completely measure it and see what's up. Perhaps I need a shorter spacer.

[Glenn Thoreson]

You need a second recessed hole, larger than the thread size, about half way through the back of the board. This will allow the retaining ring and spacer to properly fit onto a 1/4" thick board. You need to mark and drill a shallow hole on the front of the board for the stop/locating pin to fit into. When properly done, the shutter will fit flat on the board.

[wfwhitaker]

Sounds like the board has been drilled to accept the Copal 3 without use of the spacer. As long as the retaining ring completely engages the threads and its lip is secure against the back of the board, it should be fine without use of the spacer. The spacer allows the use of thin lensboards, such as metal boards. Often a wooden board will be cut with a rebate, a slightly larger hole as Glenn mentioned above. The spacer should be used then. But again, thicker boards don't always require it.

The little cheese head screw on the back will help prevent the tendency of the shutter to twist and loosen in the board. But you need to locate and drill a small recess for its head to fit into.

[ericantonio]

The little cheese head screw on the back will help prevent the tendency of the shutter to twist and loosen in the board. But you need to locate and drill a small recess for its head to fit into.
This sounds like the easiest solution!
Thanks everyone again!