Overhaul of Contax II

E. von Hoegh · Mar 26, 2015

APUGuser19 said:
View attachment 105813

That spring, it appears that the inner attachment is on a hollow shaft with a notch and the outer attachment is a notch in the recess the spring lives in. When installing such a spring you have to hold the spring compressed, place it in it's recess and slowly let it unwind while keeping the inner and outer attachments properly positioned. Letting the spring unwind abruptly will place far to much stain on one or both - inner and outer - attachment points.
I'm not familiar with the part of mechanism you are working on, but there has to be a way to install the spring without damaging it, and without 'special' tools; possibly by aligning the outer bend with whatever slot it seats in and using the central shaft to wind the spring up, then seating it. I'd have to see it; I'm just speculating here.

E. von Hoegh · Mar 26, 2015

As for the Contax, I did some work on the shutter this afternoon and it's about ready to go back together. There's a lot on the internet about how difficult these cameras are to work on, also a lot of very bad information about working on them. Compared to a 1936 Leica shutter they are night and day, but they aren't so much difficult as they are time intensive and unorthodox.
Put it this way, you could train someone to service the Leica - but you'd have to teach someone to service the Contax. There are some real pitfalls in the Contax shutter for the present day tinkerer. There are several taper pins that have to be removed, on the axis of the main winding mechanism, the film sprocket, and one of the escape wheels in the governor section. The average kitchen table/butterknife tinkerer will not have a good time with these; you need a drift, a light hammer, a practiced touch, and something solid to back up the shafts the pins are in - which means making special tools, in this case I was able to file up some bits of rectangular steel stock which I clamped in the vise to rest the parts on while removing the pins. You drift them out from the small end, of course.
Also, the shutter can only be stripped to the very last part by removing some riveted parts; I didn't do that. Instead I soaked in two different solvents and ultrasonically cleaned these assemblies. I don't much like doing it this way, but there isn't much choice in this instance. The parts are far cleaner than they were, at any rate.

Knjy · Mar 27, 2015

http://aki-asahi.com/store/html/curtains/shutter-curtain.php

Hi The correct ribbons are on this link. They are the right dimensions and the right material. Kiev ribbons are not correct. These slip through the bottom rollers quite easily, I stiffen the ends with superglue, trim the end at 45degrees and slip them through with a pin - same with the top roller clutch. Sew lightly, the threads simply have to hold the crease tight to each end - this return crease does the work. Too much sewing will result in the micro-catches fouling the ribbons. Otherwise - practice makes perfect and it looks like you have the experience.

Kevin

E. von Hoegh · Mar 27, 2015

Knjy said:
http://aki-asahi.com/store/html/curtains/shutter-curtain.php

Hi The correct ribbons are on this link. They are the right dimensions and the right material. Kiev ribbons are not correct. These slip through the bottom rollers quite easily, I stiffen the ends with superglue, trim the end at 45degrees and slip them through with a pin - same with the top roller clutch. Sew lightly, the threads simply have to hold the crease tight to each end - this return crease does the work. Too much sewing will result in the micro-catches fouling the ribbons. Otherwise - practice makes perfect and it looks like you have the experience.

Kevin

I have four meters of the Aki Asahi ribbon. It measures .0049" in thickness. The original Zeiss ribbons I took from the camera measure .010" spot on. Therefore, while the A-A ribbons are the correct width, material, and weave, they are not the correct thickness ergo not the correct ribbons - as I mentioned in a previous post. Also the correct method of removing the caps on the rollers, sewing the ribbon on a jig, and slipping it onto the roller. The A-A ribbon likely goes through the rollers easily because it's too thin. Trying a piece by pulling it through the buckles, the drag is quite a bit less than the Zeiss ribbon.
And no, I an not butchering the camera by crimping the buckles on the lower curtain. If need be it will sit carefully packed in a box until I find the right ribbon or figure out a way to double the A-A ribbon, which if possible will result in a ribbon of the correct dimensions all around.

Trask · Mar 30, 2015

This is a pretty schizophrenic thread!

E. -- good luck with your Contax. I've been reading because I have a IIa with a full raft of lenses (21mm, 35mm, 50mm, 135mm - still need that 85mm) and I like the camera a lot, so I figure if you can work your way through it I might be able to follow in your footsteps some day if need be.

APUGuser 19, I'm all confused -- on the 27th you're tossing in the towel, but by the 29th it's all right as rain? If so, good on you mate!

E. von Hoegh · Mar 30, 2015

Trask said:
This is a pretty schizophrenic thread!

E. -- good luck with your Contax. I've been reading because I have a IIa with a full raft of lenses (21mm, 35mm, 50mm, 135mm - still need that 85mm) and I like the camera a lot, so I figure if you can work your way through it I might be able to follow in your footsteps some day if need be.

APUGuser 19, I'm all confused -- on the 27th you're tossing in the towel, but by the 29th it's all right as rain? If so, good on you mate!

Don't do that! Pay attention to the details of my II and applying them to your IIa that is. The II and IIa are very different cameras, the basic architecture is similar - RF camera with vertically running metal shutter, lensmount, general layout, but that's all. The shutter timing is very different, too.
As for mine, Sunday I reassembled the shutter and selftimer, so all the subassemblies are ready to go back together. I tacked the shutter and back casting onto the main casting and tried the shutter a few times and all seems well so far, that is it sounds right, the slow speeds are plausible, and I see light through the shutter at all speeds. Hopefully I can get it timed and reassembled this week.
One issue I had, when I took the shutter apart I of course carefully counted the turns of pretension on the lower roller. But, when I started to disassemble it, some dried out goo let go and it unwound some more. When I took the roller apart, it had a lot of hard sticky greyish stuff on the center spring. So I'm not sure I had an accurate count. As it is I gave two turns after all the ribbon was wound up, with the curtains closed and capped. At this tension it sounds pretty nice, but we'll see what the times look like.

E. von Hoegh · Apr 1, 2015

It's alive!

OK, The camera is assembled and running. I used the Aki-Asahi ribbons, and the shutter works well at all speeds up to and including 1/250. By well, I mean good enough for E-6 film. Due to the thinness - half the thickness of the originals - of the A-A ribbons there is not enough friction to maintain a consistent slit width at the two highest speeds therefor 1/500 and 1/1250 are all over the map. While I was at it, I timed the shutter of a '69 Kiev 4 - at 1/1250 it averages over ten measurements about 820 microseconds.
The camera winds with noticeably less effort, and although it is pretty smooth you can definitely feel all sorts of mechanical events occurring as you wind it.
So, while the ribbons are unsuitable, they're useable to an extent and I'll enjoy the camera as it is until the correct ribbons show up.

E. von Hoegh · Apr 2, 2015

APUGuser19 said:
Good deal. I never doubted it. I was only luckier because I had a parts carcass to rob. Mine turned out beyond my wildest dreams. It now occupies #1 position in my gear.
To take an 80 year old camera with absolutely no available parts and completely rebuild it--that's a big deal. Congrats.

Thanks. The camera is in fantastically good condition inside, I could find no sign of wear anyplace. So, all it really needed was to be taken apart and the 79 year old lubricants cleaned out, then reassembled with modern lubricants - lubricants being something that has improved greatly since 1936. Oh yeah, there was the bubonic plague too.

As for spare parts, there are two options: one, cannibalizing another Contax which is unacceptable unless the carcass is not otherwise salvageable. Two, use Kiev parts. This isn't as horrible as it sounds. I could replace the original curtains and rollers with ones taken from a Kiev, which would solve the ribbon problem. By fitting the rollers to the camera, and carefully preserving the originals, the camera could be returned to it's original state with some screwdrivers and a few hours labor. Either option would involve fitting the new parts to the camera, not the other way round. The original Contax curtains have leather strips running along the sides to keep the slats from moving laterally, the ones in mine are still good (!) but that state might not last very long; this would mean new curtains or repair the old. It looks like you'd get one chance to open the brass tabs and bend them back over new strips (or perhaps something more permanent, like monofilament) to repair the curtain. The Kiev curtains use some synthetic material, I don't know what.

Milandres · Apr 4, 2015

New poster here.
You mention the leather strips along the outside curtain margins.
I recently acquired a nice war period Contax III with a 2/50 sonnar.
The shutter was jammed but the price was too good to pass.
This is my first Contax but I've had Kieves before and I am hoping I can bring it back to life.
When I disassembled it I found the shutter ribbons were original and in great shape.
The problem was with the thin leather strips on the sides of the curtain blinds.They are falling appart and allow the shutter slats to shift laterally all over the place and jam the mechanism.
I think I can replace those darn 1mm wide strips, but with what ? Fishing line ? Dental floss ?
Any advise/idea is sincerely welcome and appreciated
Mel

Grytpype · Apr 4, 2015

I'll second the above! I had always assumed that the Contax and the Kiev both used the same narrow leather strips, and I have always worried about them, though I haven't had to deal with broken ones yet.

I can imagine that it would be pretty impossible to cut a strip of leather narrow enough, yet strong enough to do the job. A synthetic material might be a better prospect if it was durable and flexible enough.

Has anyone actually had to replace these strips, and if so, what did they use?

Steve.

E. von Hoegh · Apr 4, 2015

"I think I can replace those darn 1mm wide strips, but with what ? Fishing line ? Dental floss?"

"I can imagine that it would be pretty impossible to cut a strip of leather narrow enough"

I think they are closer to .5mm. Of course, this is based upon looking at a healthy set of shutter curtains.
I played around with a machinist's 6" rule and some thin leather, it's no big deal to cut very narrow strips with a single edge razor blade.
As a substitute material, monofilament fishing line of an appropriate diameter is what occurred to me. I'm using a spinning reel that has had the same line on it since I was 17 - I am now 54, so durability shouldn't be an issue, also monofilament line has improved quite a bit since 1978 particularly in UV resistance - although this might not be an issue inside a Contax.

The real problem is the brass slats - I don't think there's a second chance to bend the tabs open and closed.

Substituting Kiev curtains and preserving the original aus Dresden curtains might be the most practical option.
The oldest Kiev shutter I have access to is from 1959, the strips are some sort of very wiggly synthetic. I'd be willing to wager that early Kiev curtains had leather strips.

Milandres · Apr 4, 2015

Yes, fishing monofilament might do the trick. It would have to be rather thin to keep the curtain as flexible as possible.
Like you said you probably won't get too many chances to bend/unbend those little tabs.
Well, I opened up all the tabs on the upper curtain.For some reason the lower curtain is in good shape.
It was a piece of cake,using nothing but a sharp scalpel and 3+ reading glasses . I bent up the tabs just enough. Not more than 90 degrees at the most. The leather strips that fell out are not only narrow but also paper thin.
I am amazed at the precision in the way these slats hinge with each other !
Working on these cameras is truly awe inspiring
Mel

E. von Hoegh · Apr 4, 2015

Milandres said:
Yes, fishing monofilament might do the trick. It would have to be rather thin to keep the curtain as flexible as possible.
Like you said you probably won't get too many chances to bend/unbend those little tabs.
Well, I opened up all the tabs on the upper curtain.For some reason the lower curtain is in good shape.
It was a piece of cake,using nothing but a sharp scalpel and 3+ reading glasses . I bent up the tabs just enough. Not more than 90 degrees at the most. The leather strips that fell out are not only narrow but also paper thin.
I am amazed at the precision in the way these slats hinge with each other !
Working on these cameras is truly awe inspiring
Mel

Is there any chance you could post a photo of the strips?

Milandres · Apr 4, 2015

I will be very happy to post a photo.
First I will need to figure out how. I have never been much of a forum poster, rather a chronic lurker

Milandres · Apr 4, 2015

You can see some of the leather strip fragments

Milandres · Apr 5, 2015

Same image, just lightened a bit.

E. von Hoegh · Apr 7, 2015

Milandres said:
Same image, just lightened a bit.

Thank you. Measuring the date on a cent (and dates can vary in height as you may know), it looks like your estimate of 1mm was better than mine of about a half mm. But, on my curtains they did seem narrower.

As for substitutes, maybe two parallel strands of 6-8 pound test monofilament on each side of the curtain? I need to take a micrometer to a tackle shop and measure some.

Dan Fromm · Apr 7, 2015

E., while you're in the tackle shop look at microfiber fishing line. Makers claim that diameter for diameter it is much stronger and more abrasion resistant that monofilament.

E. von Hoegh · Apr 7, 2015

Dan Fromm said:
E., while you're in the tackle shop look at microfiber fishing line. Makers claim that diameter for diameter it is much stronger and more abrasion resistant that monofilament.

Is that something new, or is it a new name for the old woven/braided line I remember from decades ago?
In the shutter application (that is holding the slats aligned), the strength isn't a very big factor - something like holding parts which might weigh something like an eighth of a gram against gravity. But, for a ribbon substitute, it could be interesting - I'm thinking parallel strands. Thanks Dan.

Dan Fromm · Apr 7, 2015

E., I've never used the stuff but the propaganda says its new, not the old braided line I also remember from decades ago.

I wasn't thinking so much of strength as of resistance to abrasion.

IloveTLRs · May 6, 2015

So how did the Contax II turn out after the thorough TLC?

Xmas · May 6, 2015

E. von Hoegh said:
Is that something new, or is it a new name for the old woven/braided line I remember from decades ago?
In the shutter application (that is holding the slats aligned), the strength isn't a very big factor - something like holding parts which might weigh something like an eighth of a gram against gravity. But, for a ribbon substitute, it could be interesting - I'm thinking parallel strands. Thanks Dan.

I'd thought of using Kiev end pieces and Kiev ribbon

E. von Hoegh · Feb 18, 2016

IloveTLRs said:
So how did the Contax II turn out after the thorough TLC?

Utterly enjoyable. Due to the wrong ribbons, 1/500 and 1/1250 are unreliable of course, but otherwise it's a delight.

E. von Hoegh · Sep 7, 2018

E. von Hoegh said:
Utterly enjoyable. Due to the wrong ribbons, 1/500 and 1/1250 are unreliable of course, but otherwise it's a delight.

Still a delight.
I've found some mylar of the correct thickness, and while I will not experiment on the Contax, I've made some ribbons & tried them in a Kiev with encouraging results.
BTW the 1970 Lytkarino J9 I found on feepay is really good!

Overhaul of Contax II

E. von Hoegh

E. von Hoegh

Knjy

E. von Hoegh

Trask

E. von Hoegh

E. von Hoegh

E. von Hoegh

Milandres

Grytpype

E. von Hoegh

Milandres

E. von Hoegh

Milandres

Milandres

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Milandres

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E. von Hoegh

Dan Fromm

E. von Hoegh

Dan Fromm

IloveTLRs

Xmas

E. von Hoegh

E. von Hoegh

Overhaul of Contax II

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