Compur shutter questions

[Oslolens]

If you go to this reference: http://www.tontrennung.de/assets/doc...ur_shutter.pdf

Scroll down a bit to "Section 2 Specifications" then scroll a bit more to the specifications for the rimset No. 2 Compur you can see the mounting thread is described as having a pitch of 29 1/13 threads per inch (T.P.I.) with the angle of the threads being 50º. Then just a bit further the No. 3 and No. 4 Compound shutters are described as having the same 29 1/13 threads per inch pitch with an angle of 50º. The SK Grimes website describes these shutters as having a mounting thread pitch of 0.9 mm.

Doing the arithmetic 29 1/13 threads per inch works out to be a metric pitch of 0.874 mm which does round off to 0.9 mm.

Incidentally I have a circa mid-1960's Schneider brochure on their Componon and Comparon enlarging lenses. It shows the 180, 210, and 240 mm Componons and the 210 and 300 mm Comparons as having a mounting thread with the 29 1/13 threads per inch pitch (thread angle not given.)

David

The 29"1/13 tpi might be a joke.
According to my understanding of imperial engineering units the 1/13 could have been substituted with ,077 or 5/64.

How do you differentiate between m0.9 and m0.87 when you have 3 threads?

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[Jody_S]

How do you differentiate between m0.9 and m0.87 when you have 3 threads?

I personally don't, you would need some very expensive gear to measure that and for our purposes it's irrelevant. I would cut those threads at 28 tpi and call it a day. It will fit just fine.

[Kiwi7475]

If you know the size you can also get it from Luland.

https://www.ebay.com/itm/Luland-Larg...-127632-2357-0

https://www.ebay.com/itm/Luland-Larg...-127632-2357-0

They carry all sizes and do custom too.

I buy A LOT from them and it’s always perfect. Usually I get it in 10 days.

[PunkFunkDunk]

[QUOTE=Kiwi7475;1624653]If you know the size you can also get it from Luland.

My understanding is that Luland retaining rings are for Compur rim set shutters, not the older dial set shutters which have different dimensions.


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[Kiwi7475]

Like I said, if you know the dimensions they can do a custom size.

[Ron (Netherlands)]

If you go to this reference: http://www.tontrennung.de/assets/doc...ur_shutter.pdf

Scroll down a bit to "Section 2 Specifications" then scroll a bit more to the specifications for the rimset No. 2 Compur you can see the mounting thread is described as having a pitch of 29 1/13 threads per inch (T.P.I.) with the angle of the threads being 50º. Then just a bit further the No. 3 and No. 4 Compound shutters are described as having the same 29 1/13 threads per inch pitch with an angle of 50º. The SK Grimes website describes these shutters as having a mounting thread pitch of 0.9 mm.

Doing the arithmetic 29 1/13 threads per inch works out to be a metric pitch of 0.874 mm which does round off to 0.9 mm.

Incidentally I have a circa mid-1960's Schneider brochure on their Componon and Comparon enlarging lenses. It shows the 180, 210, and 240 mm Componons and the 210 and 300 mm Comparons as having a mounting thread with the 29 1/13 threads per inch pitch (thread angle not given.)

David

Thanks David for the link (which I should have known). Let's hope then for the OP that the modern rim-set shutter has the same dimensions as the old dial set Compur.

<edit> I have one rimset n.2 and it is compatible (the one with the Zeiss Ikon logo)...

[David Lindquist]

[QUOTE=PunkFunkDunk;1624721]

If you know the size you can also get it from Luland.

My understanding is that Luland retaining rings are for Compur rim set shutters, not the older dial set shutters which have different dimensions.


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I think you are on the right track getting a retaining ring from Phototools. Please let us know how it works out. (I gather they are more accessible to you than SK Grimes here in the US)

I did get one of the Luland's tripod heads, one based on the Ries/Baco design. I think it is quite nicely made.

David

[David Lindquist]

Thanks David for the link (which I should have known). Let's hope then for the OP that the modern rim-set shutter has the same dimensions as the old dial set Compur.

<edit> I have one rimset n.2 and it is compatible (the one with the Zeiss Ikon logo)...

Lovely collection of Compound and (mostly) dial-set Compur shutters!

To be clear for everyone I have two flanges from SK Grimes that would have a pitch of 0.9 mm, one for one of my dial-set Compurs and one for my (pre WWII) No. 4 Compound. Both fit nicely which is not surprising all things considered.

May as well note for everyone that the No. 3 Compur did not follow the dimensions of the No. 3 Compound; both its lens cell threads and its mounting thread are metric pitch (and presumably form).

David

[Chris_LF]

Did you get sorted out with Custom Photo Tools? I bought the same lens over a year ago and I am happy with the adapter for Copal 3 Jose made for me. On the invoice, it was identified as brass adapter for a Compur 2 Tube 5 shutter on a #3 lensboard + retaining ring, Item#:SH-COMPUR2/5-3-BRASS, 40 euro.

[nitroplait]

In addition, with great luck I came across this manufacturer based in Portugal, Custom Photo Tools:

https://customphototools.com/lensboa...tter-adapters/

As well as making and selling retaining rings for various shutter sizes (including older dial set Compurs), they make adapter and ring combos that will allow a 50mm X M9 Compur rear thread to adapt to to regular Copal 3 lens board hole. Very reasonable prices with aluminium costing 30 Euros and brass costing 40 Euros.

Great resource! Thanks for the heads-up. I have some old beautiful enlarger lenses with odd thread mounts that may get a second life now.