Caption on item: "Rumbling and tumbling – Hopper-loads of nails are shown pouring into one of three giant rumbling machines which form part of the tremendous equipment for production of nails at the Pittsburg, California, mill of Columbia Steel Company, United States Steel Corporation subsidiary. After hopper-loads are weighed, the nails enter the rumbling machines where they are tumbled about in a mixture of sawdust and water to removed dirt, grease, lime and tiny burrs. Fernando Garcia is shown dumping a load of nails into the rumbler as Ambrosio Medina awaits his turn."