Unusual markings on my 1/4 Plate CC Harrison portrait lens

[CCHarrison]

I wonder what you all think of the unusual markings on the back of the flange.

Please see http://antiquecameras.net/blog.html

Dan

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[Steven Tribe]

Recycling of a round brass plate from some sort of naval/surveying/astronomical instrument.
I have used all sorts of brass in making the elusive flanges

[goamules]

Wow, that is strange, especially on what would be the inside of the flange against the wood. Perhaps it's like Steven says, just a recycled ring from something else. Very cool though, and I like these early American daguerreotype lenses, as you know.

[Keith Fleming]

I think Steven is right. For an optical equipment manufacturer, there would be advantages to using brass castings that would serve on more than one type of optical device--or that could be pressed into service if regular flanges were in short supply one day.

Keith

[Vincent Pidone]

Useful for portraits:

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That's Hiroshi Sugimoto.

[Mark Sawyer]

I'll go with Steven on this one too, probably recycled from other use. The only thing I can think of for having such markings on a lens would be measuring rotation for astigmatism, but that's still a wild and pretty unlikely guess...

Is there an engraved marking on the barrel to line up with the degree marks on the flange?

[CCHarrison]

Hi Mark,

No markings on the barrel.

I could buy into the recycle theory except I have a hard time imagining what else this flange could have been previously....

Dan

[goamules]

The top of a tripod, transit, telescope mount...to start with the "T"s!

[CCHarrison]

Ah yes.... But it just so happens to align precisely with the flange for a 1/4 plate photo lens ? The markings align perfectly with the flange. I don't see how it's possible. But I'm stubborn.

[hoffner]

Ah yes.... But it just so happens to align precisely with the flange for a 1/4 plate photo lens ? The markings align perfectly with the flange. I don't see how it's possible. But I'm stubborn.

Yes, it was recycled precisely for that reason - because it happened to be precise match. A nice example of a correct early industrial economic decision. I have found such examples on other brass parts too, even if not in the optical industry.

[cowanw]

Perhaps an exam/exercise for an apprentice?