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Br1078lum
Tinkerer
Username: Br1078lum
Post Number: 85
Registered: 11-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, May 16, 2011 - 02:41 pm: | 
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Just received an I-26M in the mail, and I can't get it to mount correctly on my Zorki 1. As I start to thread it on, it binds about a third of the way in.
I cleaned the threads on both camera and lens, and checked for damage from mis-alignment or droppage. Quite frankly, I can't see anything physically wrong with this lens. It's almost as if the mount is just a little too big for the camera. Thread pitch appears to match my I-22.
Any ideas? Is this common with this lens/camera combo? I don't have another FSU body to check it out on, and I'd hate to send back such a clean looking example.
PF |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 1134
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, May 16, 2011 - 08:41 pm: |
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I've never heard of that, but I have heard of some Kiev bayonet lenses fitting some bodies better than others, so I guess you could have the same tolerance mismatch issue with the screw thread.
You can lap the threads in and make them fit by putting some silver polish (Simichrome, etc) on the threads and working them in: screw the lens in until it binds, back it off, go a little farther next time, and gradually the abrasive will remove a little metal from the threads until the will fit together. It's an extreme case, but I've made 1mm pitch threads fit into a .75mm pitch mount this way. If I can do that, surely you can make your Industar fit your Zorki. |
Br1078lum
Tinkerer
Username: Br1078lum
Post Number: 86
Registered: 11-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, May 16, 2011 - 09:48 pm: |
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Didn't have to resort to the Simichrome, Rick, but I did use the same basic process (before I read your post). I just figured the lens mount is aluminum, it will have to give sooner or later against the harder camera mount.
I still can't tell just where the deformation was, and didn't find any shavings when I got done. Which is good, because this particular camera has given me fits ever since I started to use it (had it about a year before I pulled it out of retirement to use it for ICCD on Flickr). Holes in the curtains, film chips hanging the shutter, scratches on the film (only the Ilford b&w, color film is okay). But the shutter seems to be coming back to speed with more usage, and I've cleaned the green places off. A little bit of treatment on the leather, and it will look like a right smart camera.
The lens is the earlier tabbed version, and has a very well maintained body. Hardly a scratch on it. The cap is loose but grips okay with a filter mounted. I'll still re-line it though.
Thanks for the reply.
PF |
Glenn
Tinkerer
Username: Glenn
Post Number: 924
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, May 17, 2011 - 06:47 pm: |
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Your camera will be a very early Zorki 1 or a body fitted with an early lens mount. I suspect you will find that your lens is threaded 39mm metric pitch and thread form and the mount on the body is true LTM - 39mm imperial pitch and thread form.
Whatever the cause, I have four very early Zorki 1 bodies that all exhibited this problem and as I was mounting lenses with steel or brass mounts, forcing was not an option. After much playing about with my other Zorki and FED bodies and a variety of Leitz and Russian lenses, I just changed the body mounts for later manufactured versions. Now this could all be down to machining tolerances in the Soviet factories - in those far off days tool setting seems not to have been on the Collective's agenda - but forcing certainly was not an option.
Perhaps others can cast light on the true nature of the problem if my observations with pitch gauges etc, has been sabotaged by Soviet tolerances and lack of quality control. |
Br1078lum
Tinkerer
Username: Br1078lum
Post Number: 87
Registered: 11-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, May 18, 2011 - 09:18 am: |
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Glenn, I was thinking maybe a difference in pitch also, but could not see a difference when comparing it to the I-22. Instead of being progressively tight like you would expect with a mismatch in pitch, it would come to a dead halt at a particular point. It almost spins on now, so I'm going with the 'bad spot in thread' theory. But I should get some gauges to check the pitch anyway. Going out today to give it a test shoot. Nice cloud shapes with all the wet weather we've been having.
PF |
Br1078lum
Tinkerer
Username: Br1078lum
Post Number: 89
Registered: 11-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, May 19, 2011 - 01:35 pm: |
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Glenn, mine is definitely one of the later manufactured bodies, with the metal surround on the front, serial number on the back, and the short spring plate on the bottom. It does however have the rangefinder from an earlier model with a serial number on top, so this one has been worked on before. Who knows, maybe it has an earlier lens mount on it also? But I put my new rear lens cap on the I-22 and I-26, and it fits both with no problem. This was after the force-fitting of the I-26.
Tore it down last night to see where the film scratching was coming from, and found a couple nicks on the casing either side of the film frame opening. Now waiting for paint to dry after touching up the area.
PF |
Prasanna
Tinkerer
Username: Prasanna
Post Number: 64
Registered: 10-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, May 21, 2011 - 06:16 pm: |
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I have experienced similar problems between the lenses for Zorki and those for Fed. The lenses supposedly made for Zorki [with KMZ logo] fit fairly well on to me Feds. But the lense made for Fed [marked Fed industars] do not fit easily on to the Zorkis [even Zorki 2c, 4 and 4k]. Even the Jupiter 8 made for Zorki fits only one of my Zorki 4s and not the others. This is from my limited experience on 15 bodies and 24 lenses. It is possibly lack quality control. Maisenberg warns of the same problem in his book. |
Glenn
Tinkerer
Username: Glenn
Post Number: 926
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 22, 2011 - 08:18 am: |
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Subbarayan,
I can verify your findings when we are talking about Zorki 1 and the original production FED cameras - these being the only Soviet cameras I have collected and modified.
Whilst quality control is a major factor in the later models from these Soviet factories, I suspect it plays a minor role in the lens mounting problems we have seen - there being another major player that is probably the overall culprit.
From a number of published works that have studied the Soviet habit of copying various Western inventions/product, the consensus of expert opinion is that in many cases the Soviets slavishly copied every little detail - even down to Whitworth and Unified threads. However in a number of cases with special threads that used both the imperial and metric standards in their specification, serious errors, that would could lead to interchangeability problems could and did occur.
The LTM thread is one such example - The proper and correct specification being 39 mm diameter, 26 threads per inch Whitworth form. Unfortunately for the Soviets, the fact that 1 inch converts to 25.4 mm led to the sloppy assumption that a thread with a pitch of 1 mm would do, further compounded by the fact that a metric thread form was also used (well why bother to regrind all your thread cutting lathe tools when your stores are full of nice sharp metric tooling). The same factory was producing the body and the barrel mounts, so interchangeability with another company's products probably never entered the original production specifications.
The degree of incompatibility between these early FED and Zorki products is far too great to be simply explained away by the old ' Soviet quality control' chestnut. |
Prasanna
Tinkerer
Username: Prasanna
Post Number: 65
Registered: 10-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 22, 2011 - 08:50 am: |
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Thanks Glenn for the in-depth explanation. My knowledge of cameras is very limited/meagre and confined to the samples I bought as "junk" to learn how to repair them and thus get to know the internal mechanism. I have restored a few cameras and lenses the same way an itinerant plumber would without knowing much about water supply systems or simple hydraulics.
Maisenberg does not explain many anomalies, though. For instance, a couple of problems I faced are beyond my logical reach. (1) The N26Ms marked Fed fit well on my Zorki 4s and the Mir. But the Industar 50mm f/3.5 lenses do not fit the Zorkis correctly, though the latter are said to be made by KMZ.(2) Some of the Industar 50mm f/3.5 lenses focus well to infinity and indicate infinity correctly on the scale. They make good pictures too. However, they do not tally the same on the range finder while other lenses do. Obviously, one cannot be adjusting the range finder mechanism for every lens. I can understand small variations/errors due to wear and tear of the pusher ring. But these are not small at all. There are many such. Thanks again. I appreciate your detailed comments. sp |
Br1078lum
Tinkerer
Username: Br1078lum
Post Number: 92
Registered: 11-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, May 24, 2011 - 11:05 am: |
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Subbarayan and Glenn, thank you for all the information. Guess I'm not the first (or the last) to run into this problem. My I-26M has the FED mark on the face ring, but it appears to be focusing well, from the few shots I took with it. So I'll keep muddling around with the Zorki until I get it whipped into shape.
PF |
Prasanna
Tinkerer
Username: Prasanna
Post Number: 66
Registered: 10-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 29, 2011 - 06:41 am: |
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Br1078lum! I have a couple of suggestions that you may want to try. They have worked for me some cases. (1) Check the plane of the mounting flange on the Zorki with a straight edge, rotating it to see if the flange is in one plane. If it is not then you can adjust it by loosening the screws and manipulating them until the flange is even. In some cases you may need to fix paper shims. Then the lens might fit correctly. (2) Another problem I found was that some of the lenses were mounted in the wrong helical. In one or two wrong positions they would still focus to infinity, but won't sit correctly/fully on the flange. You may have to open the lens and verify the mounting distance and adjust it to the same level as a standard lens that fits. I also guess that many of these problems are created by earlier owners and not by the factory. I have adjusted a few lenses this way. Best, Subbarayan. |
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