Recycling old springs is a fun way to make knives... (or straights I would imagine I haven't made one) but as cheap as you can get a price of steel to build a razor out if I think I would just buy a little chunk and start from there. The problem with old springs is you sometimes have little stress fractures in the steel which can cause your steel to fail during the heat treat. I guess you would only be out your time if you have some springs laying around.... but sometimes having to start over can get discouraging. Just a thought.