Janka Scale - Download PDF
The Janka rating is a measure of the amount of force required to push a .444" diameter steel ball half way into a piece of wood. In laymans terms it is a way to measure a woods resistance to denting.
Thus a common use of the Janka Hardness Scale is to determine a woods suitabliity as a wood for hardwood flooring. The higher the number the greater its resistance to denting as it lives life.