The Janka hardness test measures the hardness of wood. It involves measuring the force required to embed a 11.28 millimeter (0.444 inch) steel ball into wood to half its diameter. This method was chosen so that the result would leave an indention 100 square millimeters in size. It is one of the best measures of the ability of a wood species to withstand denting and wear. It is also a good indicator of how hard a species is to saw or nail.


* These timbers are blends of several species.
The Janka rating is the average rating for the species used in that blend.