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View Full Version : A Compound/Compur HYBRID Shutter On An Old Dagor??



leighmarrin
26-Apr-2012, 23:56
I've got a somewhat beat-up 8.25" f6.8 Goerz Dagor that I paid $40 for at an antique store. Its shutter only fires at about 1/100th for all marked speeds, it is missing a flange (about 45mm diameter on external threads), and the rear cell has some rainbow-ish seperation covering about 10% of the lens diameter. The lens serial number is 395187, marked on both cells. I'm going to improvise a lensboard--if it is at least as sharp as an old uncoated Tessar of the same focal length, I'll put some money into fixing its shutter and finding a flange.

But the shutter is mystifying to me--can't find any pictures like it via Google... While it is marked COMPOUND at the bottom, and has the Compound air cylinder on top, it looks more like a dial-set Compur. Its speed dial has the counter-clockwise arrow found on some old Compur shutters, and the fastest marked speed is 1/150th--faster than any Compound I've seen. And its T/B/I selection dial is in the typical Compur spot.

So might this be one of those cobbled-together B&J Dagors I've read about? Or some uncommon factory variant?

Thanks for any info or clues...

--Leigh M. in Santa Barbara, Calif.



http://img696.imageshack.us/img696/4186/shuttery.jpg (http://imageshack.us/photo/my-images/696/shuttery.jpg/)

Steven Tribe
27-Apr-2012, 01:10
Looks like a standard Compound shutter to me!
Compur, Compound and the many varieties of the Compound (like IBSO) were made by the same company. I think only the large sizes retained the "odd" rear 3 pin position for TBI.

leighmarrin
27-Apr-2012, 02:28
Well.. maybe I did not "Google" long enough... of the many Compound shutter images I found, none had the T/B/I setting at 9 o'clock, and none had the CCW-pointing arrow on the shutter dial. And all had the "M/B/Z" setting at the bottom at 6 o'clock.

Glad to hear it's a standard Compound--I was afraid it might be some "kluge" cobbled together from different shutter parts, and hence probably unfixable.

EDIT UPDATE: Ooops! Just "Googled" "Compound Shutter" again, and the fifth photo from Google Images is identical to mine... sorry about the wasted bandwith...

Steven Tribe
27-Apr-2012, 02:46
I believe this variation is called the compur/compound or rad-compound?
The speeds of the compounds were:

00 - 1/300
0 -250
1 -200
2 -150
3 -100
4 -75
5 -50

E. von Hoegh
27-Apr-2012, 10:43
Nothing uncommon there, it's just a late Compound. The earlier small ones had the IBT selector just above the aperture scale, the very early ones had a pneumatic release as well. I have a 6" Dagor in such a shutter.
It fires at one speed only because the piston is stuck. That dent in the front cell would make me check the parralelism of the seating surfaces. A Compur flange might fit.

Edit - It is a real Dagor.

leighmarrin
27-Apr-2012, 14:34
How would I check the parralelism of the seating surfaces? While the rear cell has a little seperation, the front cell looks fine, except for the front ring dent. Also will shoot some film thru it--hopefully it will be as good as a 21cm f/4.5 uncoated Tessar I have, or better.

I measured the OD of the mounting threads as about 45mm. The closest listing on SK Grimes' flange list is for a "Compur #2 Obsolete --43.95-M.9"

Thanks for all the info.

E. von Hoegh
28-Apr-2012, 07:06
How would I check the parralelism of the seating surfaces? While the rear cell has a little seperation, the front cell looks fine, except for the front ring dent. Also will shoot some film thru it--hopefully it will be as good as a 21cm f/4.5 uncoated Tessar I have, or better.

I measured the OD of the mounting threads as about 45mm. The closest listing on SK Grimes' flange list is for a "Compur #2 Obsolete --43.95-M.9"

Thanks for all the info.

Ideally, you would measure the parralelism by unscrewing the cells, placing the shutter on a surface plate, and measuring the height from the rear seat to the front seat with a dial indicator. Ypu could measure the parralelism with dial calipers, lacking a surface plate and dial indicator.
This lens will have more coverage and less flare than a Tessar.

TheDeardorffGuy
28-Apr-2012, 21:47
Years ago, after the Berlin wall came down I bought about 25lbs of Compound Shutters from a repair agency in Dresden Germany. Many were brand new in boxes and were made in East Germany as late as 1982. Most of them had the rocking lever TBI ot 6 o'clock. Several were just like the one in the first post. All had the temperature compensation screw. I love these shutters and remounted many lenses in them for customers.

leighmarrin
28-Apr-2012, 23:59
Ideally, you would measure the parralelism by unscrewing the cells, placing the shutter on a surface plate, and measuring the height from the rear seat to the front seat with a dial indicator. Ypu could measure the parralelism with dial calipers, lacking a surface plate and dial indicator.
This lens will have more coverage and less flare than a Tessar.

I think I can dig up a dial calipers: what sort of tolerances do you suppose would be acceptible? +/- .003" or?

E. von Hoegh
30-Apr-2012, 06:45
I think I can dig up a dial calipers: what sort of tolerances do you suppose would be acceptible? +/- .003" or?

.0005" would make me happy. .001" is probably more realistic.

leighmarrin
1-May-2012, 00:49
Half a "thou'"? Yikes.. my machine-shop days are long behind me; dunno if I can measure that closely with a dial calipers. But will try and report back, once I find my dial calipers, probably buried beneath a pile of hammers and other fine-adjustment tools.. However, as I don't do a lot of major enlargments, I'll be happy with Tessar-ish sharpness and extra coverage on 5x7, so will be improvising a lensboard/flange for testing, even if its cell-seating surfaces are out of your specs. And thanks for all the info.

--Leigh M.

E. von Hoegh
1-May-2012, 06:48
Half a "thou'"? Yikes.. my machine-shop days are long behind me; dunno if I can measure that closely with a dial calipers. But will try and report back, once I find my dial calipers, probably buried beneath a pile of hammers and other fine-adjustment tools.. However, as I don't do a lot of major enlargments, I'll be happy with Tessar-ish sharpness and extra coverage on 5x7, so will be improvising a lensboard/flange for testing, even if its cell-seating surfaces are out of your specs. And thanks for all the info.

--Leigh M.

Any good set of calipers should get you .0005" with care.
Also, the dimensions for the flange you posted... if the numbers are the ID for the flange, and the OD for the shutter, they just might work. If the pitch is right.