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Mike Kovacs
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 08, 2005 - 08:22 pm: | 
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OK - I posted about my jammed Contaflex IV some time ago and I needed to take a break from it to gain some more confidence.
I think I've located the source of the jam. There is a brass gear under the top cover that is held by one of the 4 screws that hold down the winding mechanism. When it is wiggled out of engagement, the camera winds and fires. When its engaged, the camera won't wind. With the top cover off, you can see this gear quite clearly if you peer into the mechanism.
This brass gear is what couples the sprocket and takeup spool fork to the wind knob. It is on a steel shaft and is pinned on the bottom with a rivet or smooth head screw. The question is, should this gear turn freely on the end of the steel shaft, or is the entire shaft and gear supposed to rotate? I think the shaft should be fixed because there is a flat spot on the shaft to clear the main gear that charges the shutter/mirror/flap.
Its been sitting in gun oil for an hour and shows no signs of loosening-up. I just want to know if I'm barking up the wrong tree.
Also, when I release the shutter, the mechanism winds down sluggishly. Do I need to remove the lens mount to lubricate the moving parts? I suppose there are mounting screws under the front leather?
Man I need a service manual for this one. Its a real puzzle box, for sure. If anyone could oblige, that would be greatly appreciated. Thankfully, if I can get the body running, the shutter is now accurate and the blades were already stopping down properly. I understand that the back of the shutter is REALLY complex. |
Mike Kovacs
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, April 09, 2005 - 05:38 pm: |
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I think an ANNOTATED PHOTO would make things clearer. The question is whether the gear should rotate with or independent of the steel shaft it is riveted to. |
Glenn Middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, April 09, 2005 - 07:42 pm: |
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I would think that the gear should rotate freely on the steel shaft.If the whole lot is supposed to rotate, the bearing surface in that stamped plate is very badly engineered.I assume that the shaft is held by screw and washer.If the shaft was meant to rotate there would have been some shim washers also.The shaft is broader at the top only to give a better support surface.This is to ensure that the gear stays in mesh.Try gently warming the brass gear so that it expands, or if you do not fancy that soak in WD40 or penetrating oil.I would think gun oil is to viscous.I base the above on engineering common sense as the only Contaflex IV I have had my hands on was working at the time! |
Mike Kovacs
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 10, 2005 - 07:02 am: |
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Gun oil is actually very thin and light. I also tried WD-40 and even heated it with a boiling water bath. Tomorrow I will try some harsher solvents and ultrasonics.
If anyone has C-IV parts, please write. The camera is in superb, near mint condition and I'd love to get it going again. |
Peter Wallage
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 10, 2005 - 05:50 pm: |
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I haven't stripped a Contaflex, but I would tend to agree with Glen that the gear should rotate on the steel shaft. I had a similar problem with a sleeve gear on a Contax. It took me ages to get it free. It was corroded inside the sleeve. WD 40 had no effect at all. Eventually, I decided to take a chance and used heat. After several heatings and quenching in cold water to break the corroded seal it came free on about the fifth heating. I heated the brass part gently with a tiny flame of a butane pencil torch, but if you do this then on your own head be it if anything distorts. I don't think sleeve gears like this were one of Z-I's best ideas. BTW if you use a flame heat after using WD 40 be very careful. That stuff's very flammable.
Peter |
Mike Kovacs
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, April 11, 2005 - 05:36 am: |
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Thanks - I've had somebody off list confirm that a similar gear works as I imagined on a Contaflex I that he currently has apart.
I'll try to get it free but will also try to get a parts camera. |
Glenn Middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, April 11, 2005 - 08:52 am: |
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Wrap the brass gear in a piece of copper from a 15mm/1/2 inch copper water pipe.Cut a segment out of the pipe so that the gear fits tightly.You want a snug fit 1, to conduct heat 2,to protect the gear from pliers.With the pencil butane torch just heat the copper/gear wheel,then using pliers to grip steel pillar turn the gear with other pair of pliers.If you keep the brass below red heat you will not distort it.The trick is to heat the gear just enough and not transfer a great amount of heat into the steel.Holding pillar with pliers will act as heat sink.I have used this method to remove gear pinions from miniature electric motors.As a last resort any good model engineer will be able to remove the gear by drilling out the steelpillar.a simple turning job will replace the steel pillar.That is the route I would take if parts camera not available.If you are really stuck,contact me. |
Mike Kovacs
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, April 11, 2005 - 11:53 am: |
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I want to thank you all for your help with this problem.
I did just manage to get it free. I tried Peter's method of heating with no success but 60 minutes in an ultrasonic cleaning bath with detergent did manage to free the gear. I've added a small bit of gun oil and it turns smoothly now. |
