How to unscrew front/rear cells from Apo Nikkors ?

Discussion in 'Large Format' started by joerg_krusche, Oct 5, 2003.

  1. Hi,

    I have problems with unscrewing front/rear cells from Apo Nikkor
    barrel lenses (process type). Anybody out there who has experience ?
    .. by means of solvent/acetone ?, warming up ?? etc.

    There are no problems with other process lenses, but the Apo Nikkors
    are tough.

    Thank you for feedback !!

    Best

    Joerg
     
  2. Joerg, They are just screwed in too tight, perhaps a small strap wrench would help. NEVER use any liquid of any type, you would ruin the elements if fluid gets into them, and it would not help anyway. Heat wouldn't help either.
    Paul
     
  3. Joerg,

    If it's just to clean the inner elements, check out this thread. I didn't know about the possibility of "worsening" a lens (particularly Apo-Nikkors)until reading the reply to this post from Sal.

    http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=005rOM

    Good luck.

    DG
     
  4. With my 178mm F2.5 Aero Ektars; there are dinky screws and set-screws that also must be removed; which may not always be easy to see. Often with time the threads get locked together.
     
  5. I don't know about getting them off but once you get them off very lightly coat the threads with Vaseline and you shouldn't have this problem again. Make sure you don't leave any excess on the threads, you just need a very light coat. This can also be done with your filter threads to keep them from sticking onto lenses as filters seem to have a habit of doing.
     
  6. pvp

    pvp

    First, check for setscrews or a locking ring. Then, if it can't be done easily by hand, use a soft strap wrench (FWIW Sears sells such an animal, so do a hundred others) to grab the rim of the element while holding the shutter firmly.
    Sorry but IMO, the suggestion to use Vaseline is one you should carefully consider before rejecting. Any kind of lubricant in the wrong place is going to eventually cause trouble, and it's only a short distance from the flange threads to the shutter blades. YMMV, of course...
     
  7. Alan - You apply it very lightly, not in globs that drip into the shutter. I've been doing this for nine years, ever since John Sexton suggested it in one of his workshops I attended, and have never had the problem with sticking filters, lens cells, etc. that seem to get posted here every month or so in that period of time.
     

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