Understanding the Janka Hardness Scale
The Janka hardness scale, also known as the Janka hardness test, is a procedure designed to measure the hardness or density of wood. The results of the test are used to inform consumers and woodworking professionals about how well a particular species of wood will stand up to regular wear and tear when used in flooring or furniture applications. It also gives information about how well wood floors will do, for example, when heavy objects are dropped onto them.
How the Janka Hardness Test is Performed
The Janka test is brilliant in its simplicity. In order to perform the test, a steel ball of 11.28 mm diameter is expelled into a wood sample until the ball becomes embedded to one-half of its own diameter. The force needed to do this used to determine the Janka hardness rating of the wood.
Wood species with Janka ratings indicating extreme softness, such as balsa are not suitable to use as a flooring material in part because they will be unable to stand up to hardwood floor sanding, which is periodically needed to renew floors so they look as good as new. Very hard species such as mesquite, on the other hand, will last for generations when maintained by a wood floor repair firm.
How Wood cut Alters Janka Ratings
Even when coming from the same species of tree, all wood is not alike. Wood hardness can vary depending on which direction the wood grain faces. The long side of a plank will have “side hardness” and the two ends will have “end hardness,” these measurements may not be equal.