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Copal-0 Disassembly?
I have a 90/6.8 Grandagon-N in Copal 0 that I would like to move from one lens board to another. I can unscrew the front and rear cells from the shutter but I can't figure out how to get the shutter off the board.
On the rear, there is a flange/sleeve (into which the rear cells screw) that goes through the lensboard and clearly screws into the shutter and there is a lockring on there that grips the lensboard against the shutter. I can undo the lockring with my lens spanner, but the sleeve is a T shape, i.e. I can't unscrew the lockring more than about 2mm before it reaches the top/outer part of this sleeve. So all I end up with is a loose shutter.
I've tried unscrewing this sleeve thing but it seems damn tight. Is there something I'm missing that will release it?
http://www.brodie-tyrrell.org/crap/copal.jpg
Outermost bit is the offending sleeve, thing with notches is the lockring that I can unscrew. Clearly I can't unscrew it off entirely, and the sleeve won't pass through the lens board.
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Re: Copal-0 Disassembly?
Grab the rear lens with a pair of rubber gloves, Turn it CCW , the rear cell will unscrew and come off.
Then you can loosen the notched ring and take the shutter and front element off of the lens board.
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Re: Copal-0 Disassembly?
Yeah that's what I thought too. However it's got to the point where I've applied way more force than I was comfortable with (the rubber gloves ripped where they were in contact with this sleeve).
In looking at the front cell, it also has an adapter sleeve thing, except that it stayed attached to the cell when I unscrewed it from the shutter. On the rear though, the cell came away and left the ring behind on the shutter and I can't see how it comes off. As per the picture above
The front and rear cells respectively, note the former has an additional thing on it that seems sort of functionally equivalent (an adapter from the large threads on the cell to the specific threads of the shutter it's installed in) to the one stuck in the back of the shutter:
http://www.brodie-tyrrell.org/crap/grandagon.jpg
The shutter has a Rodenstock sticker on it; did they have a habit of gluing stuff in? Wouldn't make much sense because they wouldn't know what board it'll go into...
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Re: Copal-0 Disassembly?
If you have questions and want to know 100% call SK Grimes. It loos like you can get the ring off now and remount it on another board. I would just leave it, it may be part of the optical design (element config). Gogle the lens and look at the exploded view of the elements/
Optical Construction - 6 elements in 4 groups
Image Circle at infinity - 125mm @ f22 - covers up to 5x7"
This allows shift of up to 10mm vertically and 7mm horizontally on 5x7" and 45mm vertically and 40mm horizontally on 4x5
Flange to Focal distance at infinity - 94mm approx.
Filter Size - 67mm
Look for something like this, it may show if you lens has been adapted or not
http://farm7.static.flickr.com/6041/...5384046e_o.jpg
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Re: Copal-0 Disassembly?
Poly, it looks like an adapter is still screwed onto the back of the shutter. Why it's so tight I dont know. Hopefully it's just tight, not galled or loctited. Aluminium on aluminium can be problematic when tight. You could try a bit of penetrant like liquid wrench, applying it from the outside of the ring in very small quantity - you don't want anything seeping into the shutter.
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Re: Copal-0 Disassembly?
I would be leaary of any thing like liquid wrench.It could damage coatings, I would try tow band clamps and try to turn them apart. Not quite sure why you would need to at this point, seems the shutter retiaing ring should be able to be removed now since the cells are removed.
If yyou need to measure FL and sped of the glass to the window test to see if you do have some sort of adapted lens. This is what I would do first (check the Focal length and speed). It may provide some info as to the lens you have.
To me it looks like it is supposed to be. That is me, WA lenses with lots of elemts have wierd designs. It looks normal. Check the FL and speed against the know value.
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Re: Copal-0 Disassembly?
I had the same problem when I moved a Sinar DBM mounted Sinaron (rebadged Grandagon) 90mm f4.5 into a regular Copal 1 shutter. Unscrewing the lens elements left an "adapter collar" inside the Sinar DBM mount that I could not remove. I sent it to a camera tech in the UK who managed to remove it just fine. There must be techniques for this kind of job that are known by the professionals.
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Re: Copal-0 Disassembly?
There is no glass still in the shutter, it's just a little adapter ring that converts thread diameters. Like jackpie says.
I'm going to try one of those rubber jar-opener wrenches next I think.
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Re: Copal-0 Disassembly?
Try "palming" it. Place a piece of rubber/neoprene flat on the ring, press your palm against it, and turn. You might be squeezing it oval when you grasp it by the outside diameter. If you distort the adapter, it won't unscrew.
Akfreak, if you would only read the previous posts and look at the pictures, it's very apparent what the problem is.....
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Re: Copal-0 Disassembly?
Good idea but still no go :(