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Cleaning & Repairs
Replacing Shutter Ribbons

The shutter ribbons on the Kiev/Contax have been described as the bane of this camera system and are likely to break at any moment. Well, if it does who cares, we have the means to fix it. I won't try to reinvent the wheel with this procedure and to tell you the truth I refer to Rick Oleson's brilliant web site when I do this fix myself.

http://rick_oleson.tripod.com/index-29.html

What I will do is offer a few thoughts and extra images on the process.

 

First to consider is the ribbon material itself. The ribbons have a special job and thus have special material properties. You may be tempted to go out to a craft store and purchase some sort of ribbon that dimensionally meets the specification as shown above. I did, but there is more to it.

 

When you compare the craft store ribbon to the real stuff you notice a big difference in the weave and even the feel. It is more robust. The top sample is real Arsenal ribbon, the bottom is craft store stuff. 

 

I can assure you the craft store stuff does not stand up to the rigors of use. The individual filaments of the weave tend to breakdown and fray as shown. This test example was repeated twice with only a couple hundred exposures until severe wear on the ribbon was evident. It would not take long before failure at this rate.

Real ribbon material can be acquired from Oleg Khalyavin at OK Photocameras. http://www.okvintagecamera.com/

 

It is easiest to work on the ribbons with no tension on the shutter springs but there is something to be aware of. You need to carefully keep track of how many turns are made to release spring tension all the way. To do so, you do the following: Loosen the screw that holds the tension latch by 1-1 turns. Using a fine point or a small screwdriver make sure the tension latch does not fall down when the screw is loosened. If this happens the shutter tension will instantly be lost and you won't know how many turns were on the tension spindle screw.

 

Place your screwdriver on the Shutter Tension Spindle Screw and hold it from spinning. Using another object, be it a fine point tweezers or screwdriver, move the Tension Latch down to clear the Shutter Tension Spindle Screw. You now have to be really careful that your screwdriver does not slip from the Shutter Tension Spindle Screw.

 

Using slow deliberate turns count how many revolutions of tension are in the shutter. Write this number down as you will tension the shutter by this same amount to restore proper shutter tension and speed.

 

Here's another view with the shutter removed from the camera body for clarification. You may well want to remove the shutter mechanism to work on it even.

 

I find it easiest to work on both ribbons at once and starting at the lower curtain drum take up. Here we see an old Craft Store ribbon being replaced with the good Arsenal stuff. As per Rick Oleson's web site instructions, I choose to cut my ribbon to the median value of 4" of the total range listed. I then use a pencil and mark at each end the fold lines at the distances: 1/8" at from end and 1/4" from the other end leaving 4 3/8" between fold marks.

 

A word on thread before we get too far. You can use just about anything you like but the task is made easier if you select a thread that is robust and is woven to resist fraying while worked. I suggest a synthetic material. Face it, none of us are any good at sewing so we need all the help we can get. Again, borrowing from other hobbies, I use a thread that is specific to make Fly Fishing Rods. This stuff is really tough and ties a really tight and neat knot.

 

OK, time to get started, the hardest part is fishing the ribbon underneath the milled slot in the take up drum and getting it past the spring lying inside.

 

I find it difficult to control the ribbon while one is trying to stitch the ends up. I find it useful to employ one of these little clamps to hold the loose end of the ribbon down to the body of the ribbon while stitching. I picked these little gems up at Radio Shack. They are rather inexpensive and will find themselves useful at other times.

 

I can not profess to being very good at sewing the ribbons and I find it hard to emulate Rick Oleson's diagrammatic method with any exact similarity but I try to end up with a nice, tight and neat stitched ribbon.

 

Moving to the two top ribbon connections, again striving to achieve tight and neat stitching. Any lumpy knots sticking out is sure to foul up and prevent the lower curtain latch from engaging the slot in the upper curtain adjacent to our stitch work.

 

For re-tensioning the spring on the lower drum, turn the tension setting screw to the magic number of turns that you took note of earlier. For a sanity check on curtain spring tension I find that if I suspend a 160g weight and it hangs statically then that is about right to set up the correct shutter speeds. Note though, if the shutter mechanism is slightly dirty or hasn't been cleaned in recent decades then hanging 200g of weight would better do the trick.

I find that once I start mucking about with shutter tensions and worrying about the shutter speeds I feel compelled to do a complete shutter speed test. See:Shutter Speed Tester and Adjusting Shutter Speeds

 Ribbons Revisited

I had the good fortune lately to do some traveling and checked in on a sewing accessories shop and found some ribbon that looked too good to be true. It had the same weave pattern as the Arsenal material. So, I bought the entire roll and brought it home with the hopes that I had found a cheap ribbon alternative that I could share with everyone. As luck would have it, when I laid down a strip of this new ribbon beside the Arsenal stuff, the funky new ribbon started to look suspiciously wide, 3.65mm wide in fact.

 

Not one to give up easily, I threaded both ribbons through the slots in the bottom curtain to see if it would remotely work. Not a chance! The new ribbon is clearly too wide and binds up in the slots thus when the ribbon slides through the slots there is too much friction. The Arsenal ribbon has a little extra clearance on each side of the slot. Back to searching for easily available and cheap ribbon...

 

June 24, 2007