Copal 0 retaining ring mismatch

loccdor · 2026-01-24T09:04:29-0500

The retaining ring I have which was advertised as Copal 0 threads about 1/4 of the way on a shutter then binds. It seems the explanation for this is that the ring has a 0.75 thread pitch instead of the 0.5 Copal standard. Would that be the reason? What is an economical source of Copal 0 rings that thread correctly? Thanks.

ags2mikon · 2026-01-24T09:08:23-0500

I bought some on ebay a few years ago that worked. Came from China and looked like good quality.

Ian Grant · 2026-01-24T09:12:56-0500

What shutter bis it?

Ian

loccdor · 2026-01-24T09:16:11-0500

Ian Grant said:
What shutter bis it?

Ian

Prontor-SVS from Polaroid Pathfinder Land Camera 110A

Ian Grant · 2026-01-24T10:43:08-0500

The thread pitch of Deckel and Gauthier (Prontor) shutters was changed around 1929/30 when Deckel moved to the rim-set shutter, both companies were partially owned by Zeiss.

It sounds like someone has sold you a retaining ring for a Dial-Set Compur #0, at first glance they look the same. Usually around $8 on eBay, from Chinese sellers, I've bought quite a few, all well-made, and no issues.

Ian

xkaes · 2026-01-24T10:51:28-0500

Some enlarging used a 32.5mm rear mounting thread.

Ian Grant · 2026-01-24T10:57:10-0500

xkaes said:
Some enlarging used a 32.5mm rear mounting thread.

Same M32.5-0.5.

Ian

loccdor · 2026-01-24T16:19:30-0500

Yes. I received another lens today which had a copal 0 retaining ring, and tried that ring on this shutter. It fit well. So that confirms it was the original ring that was the problem. Unfortunately these rings are being mixed in with the other ones in online sales. Thanks

Copal 0 retaining ring mismatch

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