Compound shutter sizes

[Christo.Stankulov]

So, can be a Heliar 240/4.5 mounted on a Compound IV-10 II, to be mounted on a Compur 3 shutter?

Thank you.

[Ole Tjugen]

No, as the tables show clearly a 4 is bigger than a 3.
I can assure you that is cannot, at least not without some VERY expensive machine work (and in the case of a Heliar, even that won't help since the central lens element is larger than the opening of a #3 shutter),

[Christo.Stankulov]

Thank you Ole, I did not knew that Compound is made by Compur. My problem is that I have a very nice Heliar 240/4.5 on a original Compound, but I do not have the ring to attach the lens on the lens board. And I can not find nobody do make me this ring here in Paris. There was somebody the the atelier is closed 2-3 mount ago...

[MAubrey]

So, the "tube" refers to an actual tube threaded on both sides: male into the shutter and female for the rear lens element, yes?

[Dan Fromm]

So, the "tube" refers to an actual tube threaded on both sides: male into the shutter and female for the rear lens element, yes?

Sort of. Sort of because AFAIK the tubes don't unscrew from the shutter. Female at both ends to accept lens cells. Tube length is measured from the front of the front tube to the rear of the rear tube.

[MAubrey]

Sort of. Sort of because AFAIK the tubes don't unscrew from the shutter. Female at both ends to accept lens cells. Tube length is measured from the front of the front tube to the rear of the rear tube.

Thanks. I have a Compound 4 that didn't come with it's 10/II tube. I'll be heading to the machine shop.

[seezee]

Thank you Ole, I did not knew that Compound is made by Compur. My problem is that I have a very nice Heliar 240/4.5 on a original Compound, but I do not have the ring to attach the lens on the lens board. And I can not find nobody do make me this ring here in Paris. There was somebody the the atelier is closed 2-3 mount ago...

Christo, you might try an automotive machine shop. I had my retaining rings and other pieces made by a retired auto machinist here in my small university town — surely there are such folks in the big city of Paris.

[Bemko]

The 29 1/13 tpi is very close to .75mm, which is what SK Grimes use.

I believe that 29 1/3 TPI is actually closer to 0.9mm than 0.75mm. It can be easily calculated: 25.4mm/29.334=0.866mm

I can also confirm this by measuring the outer thread of my Compoud #3 shutter - it has 5 threads over ~4.5mm, which gives 0.9mm.

The table from this site http://www.suaudeau.eu/memo/pratique..._centraux.html also supports this measurement.

[David Lindquist]

I believe that 29 1/3 TPI is actually closer to 0.9mm than 0.75mm. It can be easily calculated: 25.4mm/29.334=0.866mm

I can also confirm this by measuring the outer thread of my Compoud #3 shutter - it has 5 threads over ~4.5mm, which gives 0.9mm.

The table from this site http://www.suaudeau.eu/memo/pratique..._centraux.html also supports this measurement.

Yes, the SK Grimes website shows a pitch of 0.9mm for the flange/retaining ring thread on those Compur and Compound shutters described elsewhere as having a pitch of 29 1/13 threads per inch. I expect Ole was mis-speaking. Incidentally it looks like his last activity here was just about two years ago.

I have no idea why such an odd pitch was used; years ago I asked Steve Grimes. He didn't know either.

David

[abruzzi]

Sorry to bring an old thread back to life, but I just received a lens in a Compound shutter. I'm assuming its a #3, the shutter speed goes to 100, and it seems approximately the right size. It didn't have a flange or retaining ring, so I measured it with a pair of cheap digital calipers and the outside of the thread is 63.5mm or exactly 2.5in. I compared that to the numbers listed on SK Grimes site here: https://skgrimes.com/products/mounting-flanges/

He lists two different sizes for Compound #3--M60x.9 and M62x.9 neither of which are close to what I need. Out of curiosity (and because I don't entirely trust my calipers for fine measurements) I took a retaining ring for a Copal #3, which should be 62mm, but with a .75 thread, and it wont even fit over the rear tube before reaching the threads. So I know its definitely larger than 62mm (I wouldn't think the calipers, no matter how cheap, would be off by over a millimeter.)

I've sent a message to SK Grimes, but I thought I'd ask here as well. Has anyone seen a Compound 3 with a 2.5in thread? Or do I have something customized? FYI, the shutter is labeled "C.P. Goerz New York" on the speed dial, and it houses a "GOERZ DAGOR F:6.8 FOCUS 12 IN."