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chris burck
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, February 13, 2004 - 01:23 am: | 
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hello all.
i'm new to this forum, so please be gentle.
i recently picked some different vintage folders/folder items and wanted to give them a little tlc.
i've run in to a problem with my first project, though, as i'm unable to loosen the screws holding on the backplate of the lens/shutter housing of a compur. my understanding is that this is the preferred approach, as opposed to removing the frontplate, since in the process you're separatating the iris mechanism.
nevertheless, i decided to cautiously take a shot at opening it from the front. everything seemed ok until, as i very gingerly separated the frontplate, i heard a couple if distinct 'boings' as of springs being released. i was relieved to find that, as far as i could tell, these were for the tensioning of the shutter release lever and their mooring was not connected to the frontplate. they were easily tucked back in when i replaced the frontplate, restoring their tension.
opening the front exposed another plate, and i didn't want to risk another surprise which might be more serious. as near as i can tell, the shutter is operating the same as before. does anyone know whether something else might have come loose? would i be able to remove the other, interior plate without anything flying out? if not, what tricks does anyone have for loosenig up these screws? as simple as something like liquid wrench?
also, are there any links for servicing compound shutters?
i'd appreciate any help.
-chris |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, February 13, 2004 - 04:53 am: |
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You did not mention which type of Compur shutters you are disassembling but I think it's a Compur or Compur-Rapid, both are virtually identical.
On Daniel Mitchell's excellent site you will find a description how to disassemble it:
http://daniel.mitchell.name/cameras/compur/compur.html |
rick oleson
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, February 13, 2004 - 10:04 am: |
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First, somebody told you wrong: you can't go in from the back, you have to go from the front as you did. Generally the screws in the back only want to be removed after the shutter is completely empty (except for the diaphragm blades).
Daniel's page on this is excellent. If you want a different version of the same information, mine is here: http://rick_oleson.tripod.com/index-55.html
What is your purpose in disassembling the shutter? A complete disassembly is not often necessary, unless you need to get the blades out.
I have never encoutered screws that I could not remove in a shutter. I don't know if Liquid Wrench would work well or not; if you use it, use very little.
 = |
chris burck
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, February 13, 2004 - 07:17 pm: |
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thanks much for the links. i'll definitely take a look.
the shutter is a compur, not ~rapid. i didn't want to actually disassemble it, just expose the mechanism so i cn do a bit of cleaning. everything i've come across so far indicates that the sluggish slow speeds are most likely due to gummy buildup.
it's a bit of a relief to hear that from the rear would be the wrong approach. i much prefer not to have to mess with those screws. even with liquid wrench (no doubt, used very sparingly!), if it had any effect, i fear considerable force would be needed. you should never have to use that much muscle when working with something that small. |
rick oleson
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 14, 2004 - 09:26 am: |
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All you need to do to unsluggish the slow speeds is unscrew the front element, remove the front cover panel and then the shutter-speed setting ring/cam (not the position of this carefully so you get it back the same way; you may need to rotate it back and forth a bit on reassembly to make sure the pins drop into the openings in the cam).
Under the SS cam you will see a little gear assembly, one "gear" of which is actually a sort of star-shaped wheel rather than a gear, and engaging this is a little 2-pronged rocker that oscillates like teh pendulum of a clock as the star wheel turns. Apply one drop of cigarette lighter fluid (Ronsonol, Zippo, etc) to the spindles of the star wheel and the rocker where you see them poking up through holes in the top plate of the gear assembly. This alone is usually enough to clean up the slow speeds; you can also apply a drop to each of the other gear spindles in the assembly. Generally you do not need to lubricate these; once in a while you encounter a shutter that needs a drop of VERY thin oil on the spindles after cleaning. Apply this the same way, be careful not to over-oil it.
It may also be a good idea to clean the actuating ring (this is a ring about an inch in diameter, around the inner wall of the shutter, that moves clockwise as you cock the shutter and returns the other way on release to operate the shutter mechanism)... this can be done with lighter fluid on a cotton swab.
Do not disassemble further than this unless necessary.... it's usually not.
== |
David Nebenzahl
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 14, 2004 - 07:27 pm: |
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You didn't say whether this Compur was a rimset type (shutter speeds set by rotating a large ring around the rim of the shutter, the "newer" variety) or the older dialset type (shutter speeds set by a dial at the top of the shutter).
If it's a dialset type, you can check my web page on servicing these shutters. (If it's a rimset, these instructions don't apply; however, it may give you some clue as to what to do, as there are some similarities between the two types of shutter.) |
chris burck
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 15, 2004 - 10:54 pm: |
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yes, i did neglect to mention that, didn't i? guess i figured if i didn't specify otherwise, the assumption would be rimset. that assumption would be correct.
i do, though, have a dialset compound shutter on another camera which is going to need attention. would that be similar enough to the dialset compur to go by your page?
thanks again. |
David Nebenzahl
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 16, 2004 - 01:20 am: |
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Ooh, a Compound: I just recently rebuilt one of those. Fascinating shutter, I thought. (Surprisingly accurate considering the way they work.)
They is very similar to Compurs, and you could probably figure out the differences yourself. The Compound uses a pneumatic delay instead of clockwork, so part of the job is to clean the piston and cylinder: pretty easy to do. Plus there's an adjustment cam which makes it run faster or slower (a big screw accessible from the front of the shutter).
I should do a page on the Compound one of these days.
By the way, when someone says "Compur" I don't assume rimset, since I have and work on mostly the older ones. I guess my prejudices are in the opposite direction (the "good old days"). |
chris burck
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 16, 2004 - 04:51 pm: |
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wow, interesting. how very cool.
maybe i'll go ahead and do the cleaning if after i've finished with the compur i feel sure enough. i think i'll give the adjusting screw a try first, though.
the problem seems to be the force of the shutter release. upon releasing the shutter, the cocking lever goes through between one-eighth and one-quarter revolution of free travel before the mechanism hits what must be the pneumatic resistance. the strength of the shutter seems to completely overrun the resistance and at 1 sec setting, the times are rarely as much as 1/4 sec and usually more like instantaneous. if i hold my thumb so that when the lever is released it brushes against it, that seems to sufficiently absorb the extra shock and the shutter action goes at normal speed--
well, maybe the full job will be necessary. i just double-checked how it's working, and although the 'thumb brake' method is effective, it's not consistently so, and at 1 sec setting speeds can be as slow as 2 to 3 sec. i'm also noticing that the aperture adjustment doesn't feek especially smoothe and is occasionally very stiff at the fast end.
insofar as adjusting the speeds, as long as one speed is correct, should the rest be ok due to the nature of the mechanism? if so, does it matter whether the 'control' speed is at the fast end or the slow end? and if not, then what? |
David Nebenzahl
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 16, 2004 - 11:51 pm: |
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Something else to keep in mind with the Compound is to give the air piston enough time to settle completely at the end of its travel before tripping the shutter; if you cock the shutter and immediately trip the release, the time will be significantly shorter because the piston won't be traveling the full length of the cylinder. (Presumably, when these cameras were made, picture-taking was generally a much slower process than today.)
I notice that the one I just worked on is now way too fast: 1 second is more like half a second. They're kind of finicky to adjust. The "regular" speeds, however (1/25th and up) are actually more reliable and accurate. |
chris burck
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 17, 2004 - 11:27 pm: |
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funny you mention that. it kind of seemed like the speeds worked better when the shutter sat for a bit after cocking. not knowing how the compound mechanism works, i figured that couldn't be an accurate observation; didn't make any sense.
i'll test it out again with a pause after cocking.
i've finally got the compur open. took a while to figure out how to remove the front cover/fascia. if i were to offer any criticism of either of your pages on compur repair, it would be that the 'child proof' type maneuver required to remove the front cover could be better explained.
the inside of the shutter smells very strongly of oil, and the residues are visible throughout. from what i've read thus far, i gather that i could go ahead and give the entire assembly an overnight immersion cleaning? |
chris burck
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 18, 2004 - 12:24 am: |
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ok, the job's done. the two links rick and winfried provided served well enough as a guide. beyond getting the front cover and speed setting ring off, though, it sure looked like i was working on something completely different from what those two pages show. still, i guess i applied the solvent to the right parts because even though it's probably not dried out yet, speeds seem very crisp and accurate now.
many thanks to you guys for all your help. this forum rocks! i've got a whole stack of jobs waiting for my attention, so you'll probably be hearing a lot from me in the coming weeks! |
chris burck
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 18, 2004 - 02:58 pm: |
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well, turned out i had the two shutters mixed in my original post. it was the compound that had the stuck screws. for this reason i didn't like the idea of doing the full clean as on your page, david, but your tip about the piston was invaluable. that's pretty much all i did and it seems to be right on now. |
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