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John Shriver
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, October 01, 2005 - 12:57 pm: | 
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I'm fixing up a No. 3A Autographic Kodak Special with Rangefinder. It has a nice f/6.3 Bausch & Lomb Tessar Anastigmat lens in a Wollensak Optimo 1A shutter. (Yes, I have a stash of Verichrome Pan 122 film. My 3A's aren't shelf queens yet! Also, I've got the combination back for sheet film.)
I just replaced the bellows. Now it's shutter time.
The shutter is running slow, and a bit flaky. I can see that the protruberance on the lower right is the "dashpot" that controls the shutter timing. Is this supposed to run dry, or with the very lightest of lubrication?
How do I get the faceplate off the shutter? I see no catch, latch, or screw. The only slotted screwheads on the whole shutter are the two anti-rotation pins Kodak set in the back.
homepage (with e-mail info): http://john.shriver.home.comcast.net |
John Shriver
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, October 01, 2005 - 02:45 pm: |
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I'll answer half my question. Further staring at the shutter noticed a little lever at the right end of the slot for the aperture lever, against the top of the shutter. Slide it to the right, and it sticks out some. The front plate is now unlatched, and can be rotated a bit counter-clockwise to remove it. The classic "hidden lever". Very tricky.
I cleaned and very lightly oiled the dashpot. It's only used (much) for speeds from 1 second to 1/25. But not sure if it should run dry or oiled.
I greased all of the cam slots in the shutter speed dial.
1 second is running about 1.5 seconds, and doesn't always close. I think the shutter puts a little more force on the dashpot in one direction of blade travel than the others. (This shutter has flip-flop leaves.)
More hints would be most appreciated.
There's clearly been plenty of use, the lever that slides against the dashpot lever is clearly worn. I suppose I could solder on a bit of new metal there, if that's what it needs. I certainly greased that spot. |
Dan Mitchell
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, October 01, 2005 - 05:07 pm: |
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I see you already figured out getting the top cover off.  That was quite confusing to me as well.
I assume the "dashpot" you refer to is the pneumatic piston/cylinder that controls the speed? Normally those do not have any lubrication since they work by forcing air out past the piston. Adding oil can stop the operation completely since the oil can form a seal around the piston. You can unscrew the plated piece on the outside and try cleaning it more completely. I also used some Flitz polish (non-abrasive) on the piston and that seemed to help a bit.
Unfortunately on and old shutter like that you may never get the speeds completely accurate. Wear on the piston and cylinder will change the shutters operation. From what I have read these types of shutters were quite accurate when new, but wear on the piston and cylinder causes problems over time. That's why the design was eventually abandoned in favor of the clockworks type retard unit. |
John Shriver
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, October 01, 2005 - 05:35 pm: |
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The piston and cylinder are very nice and shiny, thankfully. I'll try cleaning off the oil.
I suspect that the problem is a combination of a slightly weak mainspring, and that wear on the paddle that pushes the piston lever, it has quite a bit of wear down the middle. That must change the leverage, and there's more friction. I suspect that there are places they should have used steel that they used nickel-silver.
Is there anything else that should be oiled in this shutter? Or is it a "run dry" unit, except for the sliding surfaces? |
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