Monday, July 8, 2013

Janka Hardness

The Janka Hardness Test is a method of quantitatively measuring and comparing how hard different wood species are. It works by firing a steel ball into the face of a board and measuring how much force is necessary to sink that ball deep enough that half of it penetrated the wood. You end up with a measure of force in foot-pounds, (it's also listed in Newtons b). This allows us to say "Wood A is twice as hard as Wood B," and to say that with the weight of real measurable lab results. (I know, this is the internet and you all want arguments to be decided by who can type with the most visible anger and rage-destroyed thought processes... deal with it).

After the jump I'll put a list of woods and their Janka Hardness rating. I'll update it periodically and link back to this post as a reference point.

Some figures for comparison:

Afromosia: 1,560 lbf
Aromatic Cedar: 900 lbf
Balsa: 90 lbf (note: that's really freaking soft)
Black Poisonwood (or, Chechen): 2,250 lbf
Bloodwood: 2.900 lbf
Cypress: 510 lbf
Hard maple: 1,450 lbf
Lignum Vitae: 4,500 lbf
Marblewood: 2,710 lbf
Pine*: 380 lbf
Purpleheart: 2,390 lbf
Soft maple: 950 lbf
Red oak: 1,290 lbf
Walnut: 1,010 lbf
Wenge: 1,910 lbf
White oak: 1,360 lbf
Zebrawood: 2,095 lbf

Hard maple is commonly considered one of the hardest domestic wood species. Note that lignum vitae (South American) is over 3 times harder.

* Really, "pine" in this instance is Eastern White Pine, which is one of three commonly used construction pine species in the United States. The others are Sugar Pine and Western White Pine, both of which are more commonly found on the west coast.

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