enlarger lens retaining ring

Discussion in 'Darkroom Equipment' started by mr rusty, Aug 31, 2011.

  1. mr rusty

    mr rusty Member

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    I am in the process of designing my first darkroom. The kit I bought included 2 x componon-s lenses for a vivitar v1 enlarger. However, the guy I got it from, who was selling loads of gear, apologised that the retaining rings for the lenses to mount them on the lens boards had accidentally been included in another lot.

    No big deal really. The lenses have 39mm threads. I bought a 39-42 stepdown filter adapter as I thought this would work just fine as a retaining ring.

    it does, up to a point - I can screw the ring on far enough to make it work, but it is obvious the threads are not the same pitch, which I find surprising, as I thought all photo lens threads were the same. on both lenses the rings "nip up" before they bottom out on the threads.

    Can anyone confirm that a 39mm enlarger lens mount thread really is a different pitch to a 39mm filter thread?
     
  2. mr rusty

    mr rusty Member

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    Answering my own question! Found elsewhere enlarger thread is M39 (LTM) which is 39mm x 0.977 which is actually whitworth 26 TPI whereas filters are 39mm x 0.5mm. Now need to find a 39mm LTM retaining ring............
     
  3. Jesper

    Jesper Subscriber

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    Or you could perhaps get a M39 lens board.
     
  4. Rick A

    Rick A Subscriber

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    If you were a bit closer to me, oh say this side of the pond, I'd give you one of my extras.
     
  5. ann

    ann Subscriber

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    you can buy "jam nuts" (that is what they are called.
     
  6. Mike Wilde

    Mike Wilde Member

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    I made a DIY fix for one of my less used lenses in a secondary enlarger -

    I made a cover out of an old 35mm film can top while this work was under way to cover the rear element, and area where light gets in to light up the aperture scale.

    Coat the lens threads lightly with petroleum jelly.

    Use hot melt 'furniture' glue. It is slow setting. Place lens in the lens board, and lay a line of this glue around the lens.

    Using lightly oiled rubber oven cleaning gloves (I used spray on cooking oil) pres the still warm and pilable glue into the gresed lens threads.

    Trim back any excess while glue is still not fully hardened.

    Wipe off oil from gloves with a lightly damp dish rag carrying dilute dish washing detergent., dry, remove rear element cover

    Voila. About 5 minutes of work, 5 minutes of clean up, $0.
     
  7. ic-racer

    ic-racer Member

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    They are not that hard to come by in the 'states' from either B&H, KEH, Ebay or Sk Grimes, but shipping to UK could cost more than the ring. Sometimes it is cheaper to buy an enlarging lens just to get the ring.
     
  8. paul_c5x4

    paul_c5x4 Subscriber

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    Mr Rusty, today is your lucky day - I have a bag-o-bits that includes some threaded rings that were used to mount a bunch of enlarger lenses. I'll need to check that they are LTM threads (I'm pretty sure they are).