Prototype View Camera Front Mechanism - Now to Build it in Brass

Discussion in 'Camera Building, Repairs & Modification' started by Steve Smith, Oct 19, 2012.

  1. Steve Smith

    Steve Smith Member

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    Attached are three quick shots of a folding front mechanism I have just built for a 5x4 camera. After many hours of looking at pictures, making sketches and crossing them out and lots of trying it out on CAD, I have CNC cut some material and put it together - and it seems to work o.k.

    I know this might not be a big deal for those of you who have already done this but for me, I felt a similar achievement to the time I first managed to make bellows.

    The mechanism is made of two materials: 3mm thick fibre glass (high temperature version of FR4 as used in printed circuit boards) is used for the two base plates and the vertical uprights and Delrin acetal is used for the two hinge blocks and the horizontal bar.

    I have created a hidden hinge by fitting a couple of M3 cap head screws which fit perfectly into a hole bored half way into the block. It is important to find screws with a smooth outer surface for this as a knurled finish will wear on the Delrin.

    I could have just drilled all the way through and hinged on the shaft of the screw but I prefer this hidden hinge method.

    Folded flat: Picture 001.jpg

    Upright: Picture 002.jpg

    And with a bit of rotation: Picture 003.jpg

    This material is easily strong enough as it is and I will probably fit it to a camera and use it like this with the intention of replacing the parts with brass. However, knowing me, it will probably stay in this 'temporary' form for quite a while!

    I will replace the M4 pillars with some nicer knurled knobs too.


    Steve.
     
  2. paul_c5x4

    paul_c5x4 Subscriber

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    A couple of thoughts - If you make the side stays longer, the front stand could then tilt forward. Most stands have slots in the vertical arms to allow the lens board to rise and fall. Aside from that, looking good. Like the hidden hinge idea if plain cap heads are available (only a few of my stainless steel cap heads are smooth)
     
  3. Steve Smith

    Steve Smith Member

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    The front standard rise and fall will be incorporated into slots in the front rather than the vertical arms This will also allow tilt.

    Like this: horseman.jpg Although that does have longer stays, but I can easily make some like that to try out.

    Putting the rise and fall into the front is a cunning plan to reduce the length of the vertical arms. I have been studying the Wista Field and Tachihara cameras and noticed that they differ in where the hinge is located and because of that, the position of the base plate when folded.

    The Wista puts the side stays to the front which means that when the camera is folded up, the base plate is pushed all the way to the back and the front is tilted forward to horizontal.

    With the Tachihara it's the other way round. When it is folded, the front is moved as far forward as possible and the front folded back to horizontal. The front rotates in the opposite direction so that in the folded state, it is upside down between the arms.

    In both cases the front needs to be moved so it is centred for folding. This requires the front to be dropped down. However, in the Tachihara style of mechanism, as the front is reversed for folding, this is actually rise when the camera is in its working position meaning that I don't have to allow for an excessive amount of fall as I would if using the Wista system.

    The nice thing about having the use of a CNC router is that I can easily make both versions and try them out!

    I actually quite like the look of this black fibre glass material. It looks a bit like carbon fibre (looks much better in real life than the pictures). I might be tempted to keep it like this. It does cost about £70 for a 12" x 18" sheet though. I'm using offcuts at work at the moment.


    Steve.
     
    Last edited by a moderator: Oct 19, 2012