Contax 2 ribbon length

richardHaw

richardHaw

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pardon me for starting this, i have been reading everywhere including perer tooke's book and i got a few numbers ranging from 114mm, 110mm and something else. mine came with about 107mm.:eek::eek::eek:

is there a definitive guide on how long these should be from the edge of the shutter to drum? this is my first pre-war contax and i dont want to screw this up. thanks in advance and apologies again for asking
 
For a Contax II : 120mm between the two folds will work just fine with some suitable ribbon.

@oftheherd : the Contax I and the Contax II have different shutters.
 
Highway 61 said:
For a Contax II : 120mm between the two folds will work just fine with some suitable ribbon.
Click to expand...

Thanks. I suppose the ribbons on mine are shorter than what's found on other cameras :eek::eek::eek:

It has been replaced by the Asahi Aki ribbons by another person. while the ribbons themselves look OK, his stitching didn't and it's getting caught by the sharp hooks.

To compound the problem, mine doesn't come with even lengths. one is a tad longer than the other. Since I am not working with original material, I need to know how long they should be exactly.

OK, so 120mm it is then, +3-5mm for stitching.

by the way, medical polyester tapes are great. I saw some being sold, they are made of silk but unfortunately they are just as thick as the Asahi Aki ribbons. I am having trouble looking for a thicker material
 
richardHaw said:
I am having trouble looking for a thicker material
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I would say that you are fighting the last war. :angel:

Look for threads and posts by ZorkiKat here. Advanced search : keyword "ribbons" combined with user name "ZorkiKat". ;)
 
Highway 61 said:
I would say that you are fighting the last war. :angel:

Look for threads and posts by ZorkiKat here. Advanced search : keyword "ribbons" combined with user name "ZorkiKat". ;)
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thanks. I saw that before I began on the contax, when I was servicing a Nikon RF :eek::eek::eek:

I am also using the Asahi Aki ribbons because they are the most easily available source here in Japan and Asahi san and I are quite OK (well, just judging from our transactions and calls on the phone).

I am going to finish this thing this weekend if I have the time. it looks like the Contax 2's shutter is going to be more reliable in the long run vs the Contax 2a design which has more things that can go wrong :rolleyes:
 
richardHaw said:
it looks like the Contax 2's shutter is going to be more reliable in the long run vs the Contax 2a design which has more things that can go wrong :rolleyes:
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This is all true, but the prewar shutter is older, so many things can go wrong just because of this, especially the thin leather cords running behind the shutter curtains blades end folds.
 
Highway 61 said:
This is all true, but the prewar shutter is older, so many things can go wrong just because of this, especially the thin leather cords running behind the shutter curtains blades end folds.
Click to expand...

That's my fear. I wonder what's a suitable synthetic material to replace the straps.:eek::eek::eek:
 
richardHaw said:
That's my fear. I wonder what's a suitable synthetic material to replace the straps.
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Pretty everything synthetic with the same diameter and strength and flexiness as those original thin leather cords will work.

But the problem is that unfolding the curtains blades ends to remove the dead leather material then install new cords would very likely make some curtains blades ends break. Those narrow brass blades aren't designed to be folded, unfolded, folded again.

Once your Contax II is serviced, clean, with a well working shutter etc, use it sparingly and keep it safe and sound as a reward of your efforts to have serviced it. Then, use a Nikon RF body (with your vintage Zeiss lenses if you want it) for your daily photographic work.

Or, prepare yourself to have to install a Kiev shutter unit in it sooner or later. The Contax II shutter was a real marvel of technology for its time, but it ain't designed to last forever, because it receives much wear on every wind and on every shot.
 
Highway 61 said:
Pretty everything synthetic with the same diameter and strength and flexiness as those original thin leather cords will work.

But the problem is that unfolding the curtains blades ends to remove the dead leather material then install new cords would very likely make some curtains blades ends break. Those narrow brass blades aren't designed to be folded, unfolded, folded again.

Once your Contax II is serviced, clean, with a well working shutter etc, use it sparingly and keep it safe and sound as a reward of your efforts to have serviced it. Then, use a Nikon RF body (with your vintage Zeiss lenses if you want it) for your daily photographic work.

Or, prepare yourself to have to install a Kiev shutter unit in it sooner or later. The Contax II shutter was a real marvel of technology for its time, but it ain't designed to last forever, because it receives much wear on every wind and on every shot.
Click to expand...

got it.

i am now at the painstaking stage of reinstalling the lower drum. it's easier to do this on the Contax 2a:eek::eek::eek:

looks like I have been bitten by the Contax bug :rolleyes:

they are lovely cameras.

I dont have a jig but I got the ribbons to be the same length as close as possible.
 
OK, i am getting fading problems with the camera :eek::eek::eek:

I wonder what I should adjust to fix this. :rolleyes: I just hope that I dont have to open this thing again because it's such a pain to put it back. hopefully, just opening the back panel will suffice
 
Fading? As in a difference in exposure across the frame?
My guess is that the ribbons are slipping in the friction buckles.
Increasing the spring tension in the bottom roller should fix that.

Alternatively you could try crimping the friction buckles slightly, but I have been advised against doing that. Someone suggested putting a bit of sheet metal in the slits, but I've never tried that.
 
Mr_Flibble said:
Fading? As in a difference in exposure across the frame?
My guess is that the ribbons are slipping in the friction buckles.
Increasing the spring tension in the bottom roller should fix that.

Alternatively you could try crimping the friction buckles slightly, but I have been advised against doing that. Someone suggested putting a bit of sheet metal in the slits, but I've never tried that.
Click to expand...

Thanks for replying.

yes, I am getting uneven exposures on certain speeds. half of the frame would be properly exposed while the other half would be over-exposed.
This is easy to remedy with the Leica-type shutters that I am so used to but I am clueless when it comes to the pre-war Contax. :eek::eek::eek:

OK, I may add a small strip of tape there to see if that will help. Ric.
 
richardHaw said:
yes, I am getting uneven exposures on certain speeds. half of the frame would be properly exposed while the other half would be over-exposed.
Click to expand...
So the two curtains are not travelling at the same speed once the shutter is fired. In this case this is a friction problem due either to the ribbons material and thickness, or to how you stitched the ribbons loops (don't have the loops make a bump under the stitches) or a more serious problem due to an half-dead bottom roller drum spring unit.
 
Highway 61 said:
So the two curtains are not travelling at the same speed once the shutter is fired. In this case this is a friction problem due either to the ribbons material and thickness, or to how you stitched the ribbons loops (don't have the loops make a bump under the stitches) or a more serious problem due to an half-dead bottom roller drum spring unit.
Click to expand...

That's exactly it I suppose :eek::eek::eek:

I am always proud to have above-average sewing skills for a man so I kept mine neat just like what I would do with Leica/Nikon ribbons! :rolleyes:

OK, I should put the bump on bottom ribbons or the upper one? I will find a way to make that bump without opening what I sown.

man I am learning a lot from you guys. I now owe you coffee!
 
The stitching 'bump' of the ribbons attached to the bottom roller should already fall in the cut-out area on the roller. (I've only replaced ribbons on the Contax I, but pretty sure the design of the rollers are very similar).

The stitching of where the ribbons attaches to the top curtain should be right next to the top curtain, and the 'extra' ribbon material should be trimmed as close as possible to the stitching, so it doesn't mess with the friction buckles.

From my Contax I v5 shutter ribbon repair.
Contax1v5_04.jpg
 
Bottom roller : the stitches must be done at some distance from the flat bar around which the ribbon loops, so that the ribbon enrolls without any bump. If there is a bump due to having stitched too close to the bar, the ribbon will enroll with an eccentric motion when the top curtain will start to travel - not good.

Top curtain : a stitches bump here is less of a problem, but it may prevent the two curtains to get linked properly once the top curtain has finished its journey.

Look at Russ Pinchbeck's photos, they are good (they apply to the Kiev shutter fitted with some Arsenal ribbon but the stitching technique is the same 100%) :

http://www3.telus.net/public/rpnchbck/replace shutter ribbons.html
 
From my last successful Contax II overhaul session, here is a photo of where the stitchings at the bottom roller should be once the ribbon has gone under the flat bar of the drum unit. Don't stitch too close to the flat bar around which the ribbon end loop runs. So you need to have enough of extra length after the ribbon folds.

overhaul77.jpg
 
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