Made of solid C65100 Silicon Bronze and manufactured to meet ASME B18.6.3 our bronze machine screws are available with a standard flat head, oval head, or a round head, with the flat and oval head machine bolts being countersunk (CSK), and the round head made for surface mounting. Trust in Fair Wind Fasteners to provide the finest in imperial silicon bronze machine screws with high quality and the largest selection of sizes available anywhere.