Janka Wood Hardness Scale
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.
It is not productive to take issue with the exact number, but rather understand the "relative" hardness of one wood to another. I say this because I know from experience that two pieces of the same type of wood, one grown quickly further south and one slowly in more northern climates will have quite different Janka ratings, just because of their individual "speed of growth"... and you certainly can't ask a wholesaler for a chunk of wood that grew on the 72nd parallel.
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.
For the woodworker it will be a good indicator on the difficulty of sawing and nailing... or maybe just moving the wood around your shop...
|Southern Yellow Pine (loblolly & short leaf)||690|
|South American Lacewood||840|
|Southern Yellow Pine (longleaf)||870|
|American Black Walnut
American Black Walnut Hardwood Flooring
|Caribbean Heart pine||1240|
|Red Oak (Northern)||1290|
|African Pedauk (Padeuk/African Cherry)||1725|
|Bolivian Rosewood /Morado||1780|
|African Rosewood (Bubinga)||1980|
|Cabreuva (Santos Mahogany)||2200|
|Brazilian Cherry (Jatoba)||2350|
|African Cedar / Bosse||2600|
|Brazilian Rosewood (Tamarindo)||3000|
|Cumaru (Brazilian Teak)||3540|
|Southern Chestnut, Tiete Chestnut||3540|
|Lapacho (usually grouped with IPE Wood)
|Brazilian Walnut / Ipe
|Brazilian Tiger Mahogany||3840|