Shutter Sizes

[John Hennessy]

Can anyone tell me what size lens board hole corresponds to the current three sh utter sizes? The hole sizes I got from the last big Calumet catalog are:

0 = 34.8mm 1 = 41.8mm 3 = 65.3mm

But those selling lens boards on ebay report all sorts of odd ball hole diameter s. Or maybe the Calumet numbers refer to something else.

Thanks.

[Michael S. Briggs]

The numbers you list are correct. In addition to the three sizes you list, S.K. Grimes lists 64.1 mm for the Copal 3S shutter (http://www.skgrimes.com/products/index.htm).

As to why some lensboards have different size holes: older shutters had a larger variety of mounting holes. Also, some people who make their own holes do a pretty crude job. Some don't know that the projection on the retaining ring is supposed to go into the hole and consequently make an undersized hole.

[Brian Ellis]

Those no doubt are the correct sizes but small variations don't hurt anything. For example a 39 mm hole will work with a Copal 1 shutter.