A tool is a tool used for cutting in mechanical manufacturing, also known as a cutting tool. The vast majority of knives are machine tools, but there are also hand tools. Since the tools used in machine manufacturing are basically used to cut metal materials, the term "tool" is generally understood as a metal cutting tool. Knives for cutting wood are called woodworking knives. There is also a special type of tool used for geological exploration, well drilling, and mine drilling, which is called mining tool.

The development of knives occupies an important position in the history of human progress. As early as the 28th to the 20th century BC, copper tools such as brass cones and copper cones, drills and knives appeared in China. In the late Warring States Period (third century BC), copper knives were made due to the mastery of carburizing technology. The drills and saws of that time had some similarities with modern flat drills and saws. However, the rapid development of knives came in the late 18th century with the development of machines such as steam engines. In 1783, René of France first produced milling cutters. In 1792, Maudsley in England made taps and dies. The earliest documented invention of the twist drill is in 1822, but it was not produced as a commercial product until 1864. The knives at that time were made of solid high carbon tool steel, and the allowable cutting speed was about 5 m/min. In 1868, Mushet in England made alloy tool steel containing tungsten. In 1898, Taylor and . White invented high-speed tool steel. In 1923, Germany's Schloter invented cemented carbide. When using alloy tool steel, the cutting speed of the tool is increased to about 8 m/min, when high-speed steel is used, it is increased by more than two times, and when cemented carbide is used, it is more than twice as high as high-speed steel. The surface quality and dimensional accuracy of the workpiece are also greatly improved. Due to the high price of high-speed steel and cemented carbide, the tool appears welded and mechanically clamped. From 1949 to 1950, the United States began to use indexable inserts on turning tools, and soon it was applied to milling cutters and other tools. In 1938, the German company Degusa obtained a patent on ceramic knives. In 1972, General Electric Company of the United States produced polycrystalline synthetic diamond and polycrystalline cubic boron nitride blades. These non-metallic tool materials allow the tool to cut at higher speeds. In 1969, the Swedish Sandvik Steel Plant obtained a patent for the production of titanium carbide-coated carbide inserts by chemical vapor deposition. In 1972, Bangsa and Lagolan in the United States developed a physical vapor deposition method to coat a hard layer of titanium carbide or titanium nitride on the surface of cemented carbide or high-speed steel tools. The surface coating method combines the high strength and toughness of the base material with the high hardness and wear resistance of the surface layer, resulting in better machinability of this composite material.