Custom Roll Dies are doughnut shaped Metal Stamps made for marking flat, concave or convex surfaces. Metal Stamp Roll dies are for use in roll marking machines, screw machines and lathes. Parts and products to be marked with a Metal Stamp Roll Die can be flat or cylindrical. A roll Die can be made of steel or brass. Steel roll dies are primarily used for bar marking and gun barrel marking, as well as for hot stamping plastic and leather products.