Scratch hardness Scratch hardness Scratch hardness tests are used to determine the hardness of a material to scratches and abrasion. The earliest test was developed by mineralogist Friedrich Mohs in 1820 (see Mohs scale). It is based on relative scratch hardness, with talc assigned a value of 1 and diamond assigned a value of 10. Mohs' scale had two limitations; it was not linear, and most modern abrasives fall between 9 and 10. Raymond R. Ridgway, a research engineer at the Norton Company, modified the Mohs scale by giving garnet a hardness of 10 and diamond a hardness of 15. Charles E.
Ichalkaranji are used in engineering and other manufacturing industries, engineering institutes and research institutes for analysis. These measuring instruments are marketed in India as well as some other countries. Measuring instruments manufactured in city by varies companies include compression testing machines, torsion testing machines, horizontal chain and rope testing machines, spring testing machine, impact testing machine, Erichsen testing machines, universal testing machines, Rockwell scale hardness tester, Brinell scale hardness tester, and computerised Vickers hardness test. The city's economy. driven by the engineering goods manufacturing industry (which has been around since the 1950s). Several automotive component manufacturers have plant's in or around