In article ,
R.H. wrote:

"Marco Milazzo" wrote in message
.. .
Hard to tell without seeing the whole piece, but #276 looks like a
universal lens mount for studio cameras. This was a device to mo9unt
any diameter lens. The iris was closed by turning a small knob on the
side.

I put a few photos of the whole piece on the site below, I think it's just
the front part of an old camera:

http://pzphotosan52.blogspot.com/

O.K. A complete shutter assembly, missing only the screw-in
front and rear lens elements.

And the cylinder is specifically for a pneumatic shutter release,
a hose to a rubber bulb squeezed by the operator.

A very slow shutter, too. Speeds of 1/4, 1/2, 1 and 2 seconds,
plus T and B (T=time -- shutter remains open after first actuation of
the squeeze bulb until the second actuation) (B=bulb -- shutter remains
open as long as the bulb is squeezed, so you open the shutter with one
hand, and trip the flashbulb with the other.)

At a guess, the 'I' (Instant?) setting is simply the shortest
time that the shutter is mechanically capable of -- maybe 1/8 second or
so.

I think that the cylinder on the otherside is a dashpot -- a
piston moving in a closed cylinder with a calibrated leak -- useful for
slow mechanical timing.

Enjoy,
DoN.

P.S. Again, posting from rec.crafts.metalworking.
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