Janka hardness test understand which woods are harder than others. 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
Walter Janka Walter Janka Walter Janka (born in Chemnitz 29 April 1914, died in Kleinmachnow 17 March 1994) was a German communist, political activist and writer who became a publisher. Janka is notable for having spent time incarcerated as a political prisoner under the rule of the Nazis and later imprisoned under suspicion of counter-revolutionary activities by the Supreme Court of East Germany, in both cases serving most of his sentence at Bautzen prison. Walter Janka was one of six children born to a Tool and die maker called Adalbert Janka. He attended junior school from 1920 till 1928. Between 1928 and