https://youtu.be/jAawhg6JtyY

Youtube vid courtesy of This Old Tony regarding the fine art of spring makery if you get stuck.

Most RC shops will have a selection of cold drawn music wire for a few dollars, you just need to come up with the correct mandrel, I have made these out of scavenged shafts with tapped thru holes and electrical tape in a pinch. Most anything fabricobbled will do.