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.
Roll hardness tester important parameters when deciding whether a paper roll is good or bad. A roll that is wound too softly can go out of round when handled. A roll that is wound too hard, on the other hand, can crack during transportation. These variations are difficult to detect. Above all, it is typically the variation in hardness across a given roll that relates most directly to such converting issues with soft edges being perhaps the biggest contributor. Roll hardness tester A roll hardness tester is a device to measure the roll hardness, hardness profile and hardness variation of paper rolls. In