AArgh - lensboard jammed!

[Ole]

Dear friends:

I have a nice, little Angulon 120/6.8 mounted on a lensboard for Technika 5x7. This is all well, but since I also have a Super-Angulon 121/8 (nice, but not little) I figured I'd move the 120 to a Technika 4x5 lensboard to use the extra coverage on 4x5 as opposed to having no movements at all on 5x7.

and now the retaining ring is stuck. Firmly. I just received a lens spanner wrench from S.K.Grimes (they are still in business, and I the wrench took only 4 days from USA to Norway!), but the ring is still seriously jammed.

The ring is jammed a little bit out from the lensboard, so that the lens rotates freely in the board...

Any suggestions? Cut the ring? Cut the board? Anything else?

Ole

 

[Donald Miller]

Ole,
It sounds like the retaining ring got cross threaded (possibly there were uncut threads nearer the shutter flange. This could have happened if the lens board is thin enough to allow the retaining ring to partially move into the uncut region. If I were you, I would try to screw the ring back onto the lens...depending on how much pressure you have exerted to this point, it may be resistant. If you can do this, possibly you may be able to straighten the orientation of the ring threads to the shutter threads.

I would next probably look to enlisting a local machine shop or even SK Grimes and get the lens to them for removal of the ring. The cost may be less expensive then a replacement shutter.

Barring that, cutting the lens board would accomplish nothing insofar as your stuck ring (it would still be stuck). I would probably then try a dremel tool and very carefully work at cutting the ring. The reason that I stress carefully, is that if you get into the threads on the shutter, you can kiss it good bye.

Good luck.

 

[Ole]

You're right about cutting the board, of course. Silly me. i must be getting desperate here

I'll give it some more tries, and careful application of a penetrating oil, before I warm up the Dremel.

To work off the frustration, I took the big 121mm and the big 5x7 camera for a walk. I'm of to the darkroom in a sec...

 

[Aggie]

..

 

[Jorge]

Hey Ole, I love my SK panner wrench also......I have has this happened to me before, and what I did was tighten the ring again and try and work it out again. Hopefully as Donald said the threads are not crossed and the ring is only misthread, by tighten it again you sort of realign the threads and it might be able to come out. It worked for me, hoepfully it works for you too.....good luck buddy.

 

[fparnold]

Let us know what your solution is. I have a 203 Ektar that came back from the shop thoroughly adhered to its lens board. I ended up making a 4" to B&J lens-board adapter, rather than fight it, but that only works if the stuck lens-board is smaller than the alternate camera.

(I can also say that 4 boards for the beast later, that were they still in business, the woodworkers at Deardorff and Co. would have nothing to worry about from me)

 

[Ole]

Still stuck...

Back to the darkroom after leaving a tiny drop of gun oil on the threads - let it soak for a while before I try again. The condensors for my Durst 138S arrived today too, so I've got another toy to play with a while...

 

[Ed Sukach]

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (OleTj @ May 12 2003, 08:55 AM)</td></tr><tr><td id='QUOTE'>Still stuck...

Back to the darkroom after leaving a tiny drop of gun oil on the threads - let it soak for a while before I try again. The condensors for my Durst 138S arrived today too, so I've got another toy to play with a while...</td></tr></table><span class='postcolor'>
Oh boy...

I've had similar over-tightening happen before. One thing that has worked is to *gently* - make that ***gently*** clamp that puppy in a vise, using leather as "protection", and ... I use a jeweler's screwdriver and a glass bottle - tap (and I mean TAP lightly in the right direction. Be afraid - be VERY afraid. I will allow one hour - anything less is too severe - to loosen that retainer. The glass bottle is there to FORCE me to be gentle.

So far I haven't broken anything.

Lycka till!

 

[Lemastre]

Whenever I get metal parts stuck together, I freeze them awhile in hopes the metals will shrink and enlarge any holes involved. This was recommended to me but has not yet worked in practice. I do it becaue it's cheap and easy. I've been told that when metal rings shrink, the diameter of the opening increases because the metal pulls inward on itself rather than toward the center of the circle. In a high school science class, this was demonstrated with a ring and a ball and a bunsen burner. Apparently, the perimeter of the ring doesn't decrease much, so that as the metal cools, the opening can expand while the ball shrinks. I've never tried cooling a lens, but it shouldn't hurt it.

 

[Ole]

Eh no - when a metal ring shrinks, the diameter DECREASES. That is becaus expansion and contraction are a linear function of the length, so that because the circumference is much greater than the thickness, the ring contracts.

But if I could freeze the shutter and heat the ring... Problem is heating only the ring, of course.

 

[Aggie]

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