View Full Version : Problem fitting Boyer Beryl in shutter

15-Dec-2011, 13:56
I own a Boyer Beryl 210mm in Compur No.1 shutter, which is a nice post-WWII coated Dagor, with ample coverage for 5x7".
When i saw another example, in barrel, on Ebay, i decided to place my bid, a very low one, and i eventually won the lens.
The idea was to put the cells in a No.1 shutter, for a friend.

The description reported a non-working diaphragm, but it took very little to reseat a misplaced iris leave, and now the lens is perfect, with spotless glasses.
The barrel is of the blunderbuss type, with the diaphragm ring that's also a lens shade.
When i took out the cells, the front one went on the front of a No.1 shutter, while the back cell couldn't engage in the shutter thread.
The problem lies with the length of the back cell thread: the shutter thread and the cell thread are made the opposite way.
In the shutter, the thread starts after a couple mm, the end towards the rim is without thread, and slightly tapered. In the cell it's reversed, the thread starts from the outside, and the last 2/3mm are recessed, with no thread, and slightly tapered towards the end of the cell.
I hope i made it clear, the the ends of the two parts that should screw one into the other have no thread, so that the male and female threads don't come in contact one to the other.
It's a pity, because the spacing would be exact, and the threads are perfectly compatible.
I tried to find a No.1 shutter which has the thread that goes all the way up to the rim of the back "tube", but i found that all the shutters i tested are made the same. IIRC, i tried Prontor/Polaroid, Copal/Polaroid, Copal Press (recent version).
Any advice?
Are pre-WWI Compurs made the same way?

It's a problem that could see Dan Fromm come to the rescue.
He is very experienced about Boyer lenses, and i remember one of his posts where he reported that some Polaroid shutters have the diaphragm at a different plane.
As far as i remember, the spacing was the same, but the diaphragm was a little advanced (or recessed), if compared with conventional Compur/Copal No.1's.
If it's little advanced, i could remove, say, 1mm from the back rim, and make a simple 1mm shim to be placed behind the front cell.

The other option would be to fill the non-threaded part on one of the two sides, with soldering compound, and try to cut the thread on it.
Not exactly simple, as the thread on the soldering should be accorded with the existing thread :(
It would be a big pain where the sun doesn't shine... the best way i could image would be to screw a male threading bit in the shutter, and try to fill the empty threads with melt soldering compound. A risky business, even after protecting shutter and diaphragm leaves as best as possible. I don't think i'm so daring... i should try first with a non-working shutter!

Another small "cells in shutter" question:
anybody out there tried to fit an f/4 80mm Componon-S lens cells in a No.00 shutter?

have fun


Dan Fromm
15-Dec-2011, 16:09
CJ, I'm away from home, can't take a look at my 210/6.8 Beryl in barrel. Its cells go into a #1 with no problem. IIRC all of my #1s have rear threads with no gap, but since I'm on the road I can't check. Next week ...