Well this project has dragged on a bit but I'm pleased to say that I ordered the die to be made a few days ago for stamping the phoshor bronze material and the contacts arrived this morning. They are silver coated copper and were surprisingly expensive (I guess it's the silver part that makes them expensive?).

While I'm waiting for the stamping die to be made I can make up the two other simple dies we need "in-house". One for riveting the contacts to the spring metal and the second for creating the 'crease' for the bend in the part.

Minimum order for the contacts is 10K pieces but I have other uses for them as well as this project.

For what looks like a pretty simple part it actually involves quite a lot of effort to make.