Aluminium rods are used to make rivets, nails, screws, and bolts. An aluminium bar is easy to drill, saw, punch, and machine, and an aluminium pipe is corrosion-resistant and used for railings, shelving, and framing. Aluminum tubes tend to have thicker walls than pipes, and are measured by the outside diameter, while tubes are measured by inside diameter. Aluminium comes in other construction applications as well, including aluminum sheets, used in aerospace, transportation, and construction jobs. Aluminum treads are grated, lightweight stairs steps used in many industrial and commercial applications, while aluminum gratings are used in many architectural interior and exterior designs. And Aluminum channels are u-shaped, lightweight, and excellent for welding.