I want to make a relativelly small diaphragm spring for a project of mine. I'm thinking somewhere around 50-70 mm diameter, I can size the other parts to match the spring.
It's basically just a cone with some cutouts.
I have a sheet of material that I've been told is Phosphor bronze. I've measured it and it appears to be 0.2mm thick. According to Wikipedia
Phosphor bronze is used for springs, bolts...
Which makes me think this could work. The problem is I don't really know how to work this material. In particular, I need to turn it from a flat piece into a cone and most likely add some reinforcement pieces to the 'fingers', though I could probably make do with bolting those on.
So the main question is: How do I go about turning a flat sheet into a cone? Do I stretch it somehow? Or should I make a circular cutout and join the edges somehow? Do note that I don't a lot of force from the spring. Worst case I'll make several and put them together.
In terms of tools I'm decently capable with a soldering iron (soft soldering) and have access to a drill that has an attachment that is meant to make it usable as a primitive lathe. Those are all that seem relevant right now.
Now, to avoid the XY problem, I shall describe the X as well.
I want to make a small model of a manual automotive clutch for myself. The key piece that I've been unable to get is the spring. Thing is, I want one that is way smaller than the ones in cars and those that are sold at that size are mostly gonna be way too strong for my application, as they are made for strength, not for looks.
I don't mind if what I make is weak, it's not meant to transfer power, it's meant to look realistic and that is my end goal.
Attempt number 1: https://i.stack.imgur.com/05qQr.jpg