What tree does the hardest wood in the world come from?
The hardness of wood has a unit of measurement, Janka hardness, which means the force required to embed a steel ball with a diameter of 11.28 mm (7 ⁄ 16 inches) into half of a wood sample, so the unit of Janka hardness is pound force (lbf) or Newtonian (N).
There are two test methods for Janka hardness: the hardness test for the front-pressed steel ball is called "side hardness", and the hardness test for the side-pressed steel ball is called "end hardness". In most cases, the hardness value you see labeled is "side hardness".
There has been a table circulating on the Internet showing the names and data of the various woods with low to high hardness of Janka, the hardest of which is from a tree produced in Australia, locally known as Bulge, latin nameD Allosasuarina luehmannii. This wood seems to be called iso-fruit casuarina in China.
On this table, the Janca hardness of this wood is 5060ibf, which is 22500N. That is to say, if you want to press the small steel ball used for the test into half a depth on this kind of wood, then you need to apply more than 2294 kilograms of pressure on it, right?
We know that wood is a natural material with different texture densities. Therefore, the hardness detection sample will generally test the hardness of three slices, usually represented by the chord section data, and then detect 3-5 data at a specified distance in the same wood sample to take the average.
The 5060ibf data is said to come from the databa wood database, a private timber database created by Eric Meier, who began building the database in 2007 and has now collected more than 600 kinds of wood data.
Interestingly, shortly after this hardness chart came out, databa wood adjusted the hardness data of isothoma, adjusting the janka hardness of this wood from 5060ibf to 3760 lbf (16740N), for unknown reasons.
Currently at the top of the site's hardwoods is a south American tree, Quebracho, Latin name Schinopsis balansae, Chinese known as red solid wood, red axe wood, belongs to the genus of broken axe wood in the family Sumac. The Spaniards gave the wood the nickname Axe Destroyer. I seriously suspect that this is where the name "Broken Axe Wood" comes from.
#Wood #Carpentry # #红木 #
