It's no fun not to ask! What are you making your own screws for? You need Bolts because you are nuts. LOL.
I just couldn't resist making a little fun. Anyway, modern methods do not use a single tool to do this. The metal is shaped forged and machined using various manufacturing process. This has brought the cost per piece down to what it is today. Are you trying to make a vintage hand made look? Maybe you could take a store bought fastener and make the head look hand forged by distressing it. Maybe making it out of round with a vise and dinging it with a hammer or something.