Identifying the thread size and pitch of brass lens

[jonbrisbincreative]

I recently picked up an early 20th century brass lens that seems like a European lens branded with an American photo supply business name. There is no flange with the lens so I need to identify the exact size and pitch of the thread so I now what kind of flange I need. How do I go about doing that?

Specifically I wonder if I just take some calipers and measure the diameter of where the threads are? Wha about identifying the pitch of the threads?

Thanks in advance.

[Jac@stafford.net]

I don't know where you live, but at my local Ace Hardware they will let me use their thread pitch gauges. You can buy your own gauge, but the good ones are expensive.

Then there is the difficulty of any seller knowing what pitch his flange has. Most do not.

If you can describe your lens or post a picture there is an outside chance I have such a lens and can measure mine.

[goamules]

Finding a matching flange for most French lenses is pretty hard. British Dallmeyer, Ross, and Taylor T Hobson are standardized, and pretty easy to match up. The others are quite difficult.

[jonbrisbincreative]

I don't know where you live, but at my local Ace Hardware they will let me use their thread pitch gauges. You can buy your own gauge, but the good ones are expensive.

Then there is the difficulty of any seller knowing what pitch his flange has. Most do not.

If you can describe your lens or post a picture there is an outside chance I have such a lens and can measure mine.

This is the lens: https://www.ebay.com/itm/222561853785

Thanks!

[jonbrisbincreative]

I've been trying to identify the engraving script on this lens since it looks fairly unique. Did Dallmeyer make branded lenses? The script seems very similar to Dallmeyer-branded lenses.



The slot attributed to a waterhouse stop is I think actually where the control arm for the iris would go. I wonder if it's been removed.

Looks like maybe this is a late-19th century lens rather than an early 20th. Any guesses on the F-stop?

jb

[Leszek Vogt]

Having the right equipment helps (not always). If you take it to your friendly machinist....presumably you have one nearby....he/she can magnify the existing thread and will be able to match it; therefore, be able to cut it with proper tool that goes with that. I had similar flange done this way on a 100+yr old Voigtlander optic.

This operation shouldn't be more than $75, tho in most cases it could be $50. Also, it depends if you rather have brass vs aluminum.

Contact me if you need more help with this.

Les

[RedGreenBlue]

Just a few thoughts.

Have you considered using an iris lens holder for your flange-less lenses? I use one to mount a variety of lenses and it saves me money and trouble. You will need to locate one that is sized to fit on your choice of lensboard. And they can be expensive, especially if you are only playing around with a single lens.

Also, I have a number of flanges laying around with nothing to do. If you would measure the diameter across the threads (in mm and inches) and also determine the pitch I can check my stash. If you don't have a pitch gauge, hold a ruler against the threads and count the number of crests that evenly fit into a certain length. For example, 5 crests in 3 mm or 7 crests in 1/4 inch, if I'm making sense. It would be good to do this in metric and imperial units. I'll see if I have a flange that is similar.

Scott

[jonbrisbincreative]

Also, I have a number of flanges laying around with nothing to do. If you would measure the diameter across the threads (in mm and inches) and also determine the pitch I can check my stash. If you don't have a pitch gauge, hold a ruler against the threads and count the number of crests that evenly fit into a certain length. For example, 5 crests in 3 mm or 7 crests in 1/4 inch, if I'm making sense. It would be good to do this in metric and imperial units. I'll see if I have a flange that is similar.

Scott

I'll definitely take you up on that. Thanks!

[Jac@stafford.net]

Just a few thoughts.

Have you considered using an iris lens holder for your flange-less lenses? I use one to mount a variety of lenses and it saves me money and trouble. You will need to locate one that is sized to fit on your choice of lensboard. And they can be expensive, especially if you are only playing around with a single lens.

Good idea, and once we get a universal iris-type lens holder we are likely to try more odd lenses. OP - there is a reasonably priced one on the big auction site right now, but it will require a large lens board or adapter to a smaller one.
.

[Steven Tribe]

I've been trying to identify the engraving script on this lens since it looks fairly unique. Did Dallmeyer make branded lenses? The script seems very similar to Dallmeyer-branded lenses.



The slot attributed to a waterhouse stop is I think actually where the control arm for the iris would go. I wonder if it's been removed.

Looks like maybe this is a late-19th century lens rather than an early 20th. Any guesses on the F-stop?

jb

Neither Dallmeyer or Ross sold "brand" lenses, except, perhaps, for the anonymous lenses bought up by the UK military.
Not a Dallmeyer engraving, either. I would have said the engraving was made locally. There are lots of city establishments in the USA, apart from organisations like B.French, who made quite attractive engravings. It is an iris lever slot and the settings can be seen. F8 rectilinear? The text for the plate size is special in the way the decimals are done and the big "X". There were engraving machines available at this time, which might account for the "oddities"!