What torsion springs for 4x5 camera rear stand?

[andratos]

Hello! I am in the process of designing and 3D printing a 4x5 camera, and I am now trying to figure out how to connect the ground glass frame to the rear standard. I have seen online different ways to do it: elastic bands, leaf springs and torsion springs. My favorite way which seems the most convenient is the way that the Chamonix cameras use: a pair of torsion springs. However, looking around internet, I am overwhelmed with the amount of choice. I have no idea what coil diameter, number of coils, etc, I should use for this project. I am also confused because I believe I should use a torsion spring angle greater than 180 degrees (like 225 or 270 degrees), but when I check European suppliers (such as Misumi) I only find springs up to 180 degrees (this made me think that maybe there is equivalence between different angles, but I am unsure about this). Do you have any idea of what type of torsion springs Chamonix uses in their cameras? Thanks!

[TorontoBuilder]

Even if someone who owns a chamonix camera is willing to take their back apart to access the torsion springs to photograph and measure them you will still not have the torque rating of the spring to go with the other specs such as the leg length, the deflection angle, the winding direction, and shaft diameter to make ordering springs easier. Then even if you have all that information the issue becomes matching the other geometry of the ground glass retainer/spring.

I have a complete metal working shop, lathe, various bending mandrels and a heat treating oven to make my own springs as needed and despite this if I was making a one off camera I'd choose to go with the simpler route of an elastic bungie cord, or perhaps a simple leaf spring. Even a simple leaf spring requires the correct thickness of untreated spring steel, the ability to precisely bend the material to shape and then heat treating the spring to have it be able to retain the shape.

Or contact Chamonix and claim your springs broke and you want to buy replacements

[Mal Paso]

Calumet/Cambo SCs have a bail handle with 2 leaf springs and I've seen a lot of backs or rear standards sold separately as parts. It would be simple to attach the springs to your new camera and the bail lifts the ground glass clear of the holder better than a lot of designs.