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Thread: Alternative Material for Spring Back Springs

  1. #1

    Alternative Material for Spring Back Springs

    I am (slowly) in the process of making a folding 5x4 field camera after my first effort which was a non folding heavy beast as I posted here about 18 months ago.

    Before I start cutting up wood, I decided to make some of the parts out of materials I had at work to check that everything works.

    In the attached pictures you can see the back plate with a spring loaded ground glass frame.

    The grey parts are cut from 9mm thick nylon, the brown parts are a 3.2mm thick composite material and the green parts, the springs, are 1.6mm thick FR4. This is the fibreglass material used for printed circuit boards. In this case with the copper etched away.

    I will probably try to get some spring steel when I make the back properly from wood but these fibreglass 'springs' work surprisingly well.

    I have use of a CNC drill/router intended for PCB production so it is quite easy to try out various options - much easier than if I had to cut it all by hand.

    Has anyone else tried a non-metal or unusual material for their springs? Attached files

  2. #2

    Alternative Material for Spring Back Springs

    And again....

    Attached files

  3. #3

    Alternative Material for Spring Back Springs

    Nice looking camera back. I STILL envy you for that CNC router!

    I would not have thought about FR4 for springs, but it's an interesting idea. Are you finding it to exert sufficient force?

  4. #4

    Alternative Material for Spring Back Springs

    I made a mock-up using wood, 1/4' brass nut'n'bolts and steel compression springs that was based on the "razzlok"
    http://homepages.ihug.com.au/~razzle.../razzlok_.html
    my version worked but it was a bit combersome, but then, I have trouble making anything complicated....

  5. #5

    Alternative Material for Spring Back Springs

    Quote Originally Posted by moot
    Are you finding it to exert sufficient force?
    The problem is that with the filmholder in place there is a bit too much force and with it out there is not quite enough. I am going to try thinning down the strips and increasing the angle.


    Steve.

  6. #6
    Administrator Tom Persinger's Avatar
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    Alternative Material for Spring Back Springs

    very nice... ralph young was using tines from a garden rake as the spring steel for his backs..

  7. #7

    Alternative Material for Spring Back Springs

    Along the lines of thining the strips, it's probably not easy to find thinner material, but if you could, 2 layers of half-thickness...would that help?

  8. #8

    Alternative Material for Spring Back Springs

    Perhaps 'thinning' was the wrong word. I should have said 'reduce the width'.

    Currentlty the strips are 6mm wide. I will try 5 and 4 to see what the difference is.

    I can adjust the spacers under the screws to give sufficient force to hold the glass holder down to the back (without the filmholder in place) then adjust the width so the force isn't too great when inserting the filmholder.


    Steve.

  9. #9
    Administrator Tom Persinger's Avatar
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    Alternative Material for Spring Back Springs

    keep us posted, this looks great!
    thanks Steve.

  10. #10

    Alternative Material for Spring Back Springs

    Quote Originally Posted by apn
    my version worked but it was a bit combersome, but then, I have trouble making anything complicated....
    Great to see you have a go Andrew I have tried many different compositions for this idea, including the current aluminium/Foamex sandwich. I would like to try some plastics simply because of the weight, but what worries me is the wear factor caused by constant insertion of a film holder, as any wear would soon result in a light leak. I too have resorted to the use of a CNC machine to make them in numbers, so I will now be able to try various materials to see how they perform. The current Razzlok weighs only 350g with the ground glass screen included. Springs are incorporated within the sandwich.
    Attached files

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