Janka hardness test
Test to measure resistance of wood
Janka hardness test
The Janka hardness test (English: ; German: [ˈjaŋka]), created by Austrian-born American researcher Gabriel Janka (1864–1932), measures the resistance of a sample of wood to denting and wear. It measures the force required to embed an 11.28-millimeter-diameter (7⁄16 in) steel ball halfway into a sample of wood. (The diameter was chosen to produce a circle with an area of 100 square millimeters, or one square centimeter.) A common use of Janka hardness ratings is to determine whether a species is suitable for use as flooring. For hardwood flooring, the test usually requires an 80 mm × 150 mm (3 in × 6 in) sample with a thickness of at least 6–8 mm, and the most commonly used test is the ASTM D1037. When testing wood in lumber form, the Janka test is always carried out on wood from the tree trunk (known as the heartwood), and the standard sample (according to ASTM D143) is at 12% moisture content and clear of knots. The hardness of wood varies with the direction of the wood grain. Testing...
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