Whitworth's self-acting screw feed reversing tool box planing machine, 1842. The planing machine cuts flat surfaces in metal components. This power-driven planing machine drives a cutting tool over the workpiece, removing a small amount of metal in a straight line. It then steps the cutter to one side, machining overlapping cuts until the entire surface has been covered. It was a significant improvement over previous designs, offering greater precision and ease of operation. Accurately flat surfaces were essential for a wide range of engineering products; machines like this were used in the construction of steam engines, textiles spinning equipment and to make other machine tools.