Janka hardness test Janka hardness test The Janka hardness test (from the Austrian-born emigrant Gabriel Janka, 1864-1932) measures the resistance of a sample of wood to denting and wear. It measures the force required to embed an diameter steel ball halfway into a sample of wood. A common use of Janka hardness ratings is to determine whether a species is suitable for use as flooring. The hardness of wood varies with the direction of the wood grain. Testing on the surface of a plank, perpendicular to the grain, is said to be of "side hardness". Testing the cut surface of a stump is
Indentation hardness Indentation hardness Indentation hardness tests are used in mechanical engineering to determine the hardness of a material to deformation. Several such tests exist, wherein the examined material is indented until an impression is formed; these tests can be performed on a macroscopic or microscopic scale. When testing metals, indentation hardness correlates roughly linearly with tensile strength., but it is an imperfect correlation often limited to small ranges of strength and hardness for each indentation geometry. This relation permits economically important nondestructive testing of bulk metal deliveries with lightweight, even portable equipment, such as hand-held Rockwell hardness testers. Different techniques are