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.
And with a bit of rotation:
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.