Janka Hardness Scale
The Janka Test is a measure of the hardness of wood. The Janka Test was developed as a variation of the Brinell hardness test. The test measures the force required to push a steel ball with a diameter of 11.28 millimeters (0.444 inches) into the wood to a depth of half the ball’s diameter. The diameter was chosen to produce a circle with an area of 100 square millimeters. The Janka hardness values have been indicated below on the more commonly known species.