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 1932 he undertook a type setting apprenticeship. In 1930 Walter Janka became an Organisation Leader, and then a Political leader of the Young Communists (KJVD / "Kommunistischer Jugendverband Deutschlands") for the Chemnitz sub-region. After his elder brother, , had been murdered by the Nazis, Walter himself was imprisoned by the Gestapo. He was remanded in custody in Chemnitz and in Freiburg before being convicted of preparing to commit high treason. After 1 years of imprisonment in Bautzen prison, he spent a six-month term in Sachsenburg concentration camp. Finally, in 1935 he was deported to Czechoslovakia. In 1936 Janka went to