Odd shutter sizes

[Rider]

The thread on the shutters for both the 120 dagor and 180 dagor are just a bit bigger than Copal 0.

Does this shutter size have a name?

(The 120 dagor shutter is unmarked, but seems to be a Compound; the 180 dagor shutter is a Bausch and Lomb Unicum).

[Gene McCluney]

I don't believe shutters were standardized in their thread pitch until the 1950's. Nor were the manufacturers in agreement on overall size, either.

[John Kasaian]

S.K.Grimes' website has a good article on the "#2-1/2 -ish" Compurs you might find interesting.
Cheers!

[Donald Qualls]

I don't believe shutters were standardized in their thread pitch until the 1950's. Nor were the manufacturers in agreement on overall size, either.

Depends on the shutter. I have and have had #1 Compurs from very early in the rim-set era that had modern standard threads -- but then the Compur was one of the shutters from which the modern standard was derived, so no surprise if they were first on the scene, so to speak. Every dial-set #1 Compur I've owned, so far, has had a very different thread from the #1 rim-set, leading me to think the earliest you might expect to see modern lenses fit an old shutter, or vice versa, is around the 1928 date when Compur started to convert from dial-set to rim-set.

Other manufacturers may well have continued to use their own "standards" for a longish time after that, so you might well see shutters other than Compur, Prontor, and Copal from as late as 1950 with proprietary threads...