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Thread: Cleaning up a Universal Clamp

  1. #1

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    Cleaning up a Universal Clamp

    Yesterday a 'broken' clamp arrived labelled RBM Brevet 234175. It was cheap because it was not operating as the blades were loose and disconnected inside. I've put it back together and now it works as intended but is very stiff due to rust and lubricant deposits on the blades. I will disassemble it and clean each blade and I would be grateful for recommendations as to how to do this best. Should I use emery/wire wool and then metal polish? And should the blade be lubricated when reassembled. Thanks.
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  2. #2

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    Re: Cleaning up a Universal Clamp

    This is the alternative universal iris clamp design which, I think, have an Italian/French origin.
    The main difference is that the turning mechanism is far more direct, visible and solid compared with the more common German (?) type. It is the only type I would recommend for Lenses weighing more than 750 g.

    Yours is missing the turn buckle which fits below the central screw (still present) and which has 2 lugs which fit in the 2 holes you can see.
    This is the only weakness with the system and which also was missing in the large example I renovated a few years ago.

    I would absolutely recommend rust removal and lubrication.

    Here is previous thread!

    https://www.largeformatphotography.i...is-lens-clamps

  3. #3

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    Re: Cleaning up a Universal Clamp

    Thanks Steven. That's really useful! I did some searches but somehow missed the linked thread.

  4. #4

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    Re: Cleaning up a Universal Clamp

    Now de-rusted, cleaned and lubricated and working pretty well. Just need to sort out replacements for the missing clamps.

  5. #5

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    Re: Cleaning up a Universal Clamp

    Making a turn device is a bit difficult as a simple design will foul when it is rotated. I cut a brass disc of greater diameter than geared wheel (increased torque), drilled and threaded two holes to match the two holes in the wheel and mounted brass screws of the appropriate size to fit into holes (but not screwed in). Torque is provided by two lugs mounted opposite to each other near the edge of the new brass disc. IT looks rather like a miniature salmon/trout fishing reel! Of course, the original central screw may have to be replaced (metric) depending on gauge of brass used.
    As far as I remember (mine was perfectly OK), the opposite locking mechanism is a straightforward compression screw.

  6. #6

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    Location
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    Re: Cleaning up a Universal Clamp

    Thanks Steven. Looks like I'm going to be busy - too many projects on. You description makes sense and sounds very usable so I'll give it a go.

  7. #7

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    Re: Cleaning up a Universal Clamp

    Here is a better description/photos.

    https://www.largeformatphotography.i...-Italian-model!

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