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polyglot
28-Oct-2011, 01:02
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.

akfreak
28-Oct-2011, 01:27
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.

polyglot
28-Oct-2011, 05:50
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...

akfreak
28-Oct-2011, 11:15
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/6041/6289593006_c15384046e_o.jpg

E. von Hoegh
28-Oct-2011, 11:25
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.

akfreak
28-Oct-2011, 16:51
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.

jackpie
28-Oct-2011, 18:09
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.

polyglot
29-Oct-2011, 06:12
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.

E. von Hoegh
29-Oct-2011, 07:16
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.....

polyglot
29-Oct-2011, 20:59
Good idea but still no go :(

polyglot
15-Nov-2011, 23:04
So it's been to the repairer... "we're 90% sure that it's been glued". Shit.

I really don't want to have my widest lens be restricted to use only on my monorail, especially considering I mostly wanted to do landscapes with it!

Another repairer suggested cutting a couple notches in the top of the ring about 1mm wide and deep and using them as a key to unscrew it. That's starting to sound tempting but if it's glued, I can't see it helping much or at all.

I think I might cut the lensboard down and rivet the remainder to a new smaller lensboard with a #1 or #3 hole in it. And to think I just ordered a fresh #0 board for this lens! Any suggestions related to that particular form of surgery/butchery?

BrianShaw
16-Nov-2011, 07:24
I was in similar shoes not long ago. I just took the old lens on the old lens board, and a new lens board to the repair shop and paid him to move it. In my case not only was the lens "stuck" to the flange, but I also needed the lens board machined to a larger opening size than it was. I think the cost was $35 (US) and I had $0 aggravation associated with the transplant.

E. von Hoegh
16-Nov-2011, 08:51
So it's been to the repairer... "we're 90% sure that it's been glued". Shit.

I really don't want to have my widest lens be restricted to use only on my monorail, especially considering I mostly wanted to do landscapes with it!

Another repairer suggested cutting a couple notches in the top of the ring about 1mm wide and deep and using them as a key to unscrew it. That's starting to sound tempting but if it's glued, I can't see it helping much or at all.

I think I might cut the lensboard down and rivet the remainder to a new smaller lensboard with a #1 or #3 hole in it. And to think I just ordered a fresh #0 board for this lens! Any suggestions related to that particular form of surgery/butchery?

Cover the shutter with tape to prevent swarf entering it.

A dedicated tech could remove this adapter, there are solvents to dissolve most anything. Even Loctite releases at a certain temperature. NO! don't bake it!!;)

polyglot
20-Dec-2011, 05:55
Hacky success:
http://www.brodie-tyrrell.org/apug/grandagon_hack_th.jpg

In other words, I cut the centre out of the recessed Toyo-View board it was in and screwed it directly onto a Toyo-Field board.