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 called upon to testify against Janka, with the words: Wolfgang Harich had already been convicted, and sentenced to a ten-year jail term in March 1957, in respect of the same alleged conspiracy as Janka. The two had previously worked together at the Aufbau publishing house. Harich was brought into the July show-trial by as a leading prosecution witness: his testimony now heavily implicated Janka. The two former friends would remain estranged from one another for the rest of their lives. Janka served the first part of his sentence in Berlin-Hohenschönhausen prison where he had been held on remand, but in