Find Brownell's Gun Smithing on the internet, They sell many kinds and thicknesses of "dead" spring steel to make gun springs. Camera back springs are very simple to make, and temper with a propane torch. Check them out or give them a call and tell them what you are trying to do. They have been very helpful in the past. The steels they sell are so soft you can almost cut them with a knife, they file well, drill easily and can be bent into most any shape cold. I use a jewelers saw to cut mine. Charlie.........