compur 0 copal 0 Prontor SVS/SVX - not the same size?

[koh303]

I have several copal 0 and compur 0 shutters, and various rings, and i am having a hard time matching the rings to the shutters.

Starting with a compur 0 which is holding a symmar 100mm. The ring off that shutter fits a couple of others - a copal press shutter, and a synchro compur old style shutter, but does not fit copal #0 shutters, it is just too small by 0.5mm.
Needless to say the Copal 0 rings are no help here as they are too big.

When i went to order some new rings on the bay, they are all listed as if they are the same "copal/compur" etc size #0.... Clearly they are not the same - anyone know where to get compur size #0 rings (other then grimes)?

[Leigh]

For a very long time, each manufacturer defined its own set of interface dimensions.
That includes the size/thread of the mounting ring and of the front and rear element groups.

That all changed perhaps 50 years ago, when the makers standardized those dimensions.

I'm sure somebody here knows just when that happened.
It might have been during WWII due to government procurements.

- Leigh

[koh303]

At least 2 of these lenses are fairly recent (i hazard to guess) - 70's..?

[Jim Galli]

I'm having a hard time with a ring fitting a Copal 0 Press and not a Copal 0. That's just weird. I've had hundreds of these over the years and always just mixed and matched with no problems. Now Copal 3, that's another kettle of fish. Seems to be at least 4 different sizes for them, but Copal 0 and Compur 0, Copal 1, and Compur 1 I've never had an interchangeability problem. I suppose tooling wear over the long production haul could cause something like this though.