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important than all others in determining the basic suitability of a wood for a martial arts
weapon. That test is the Janka hardness test. The test is done with a hydraulic press with
a pressure gauge, and a steel ball that measures .444" in diameter. The test is done by
pressing the ball into the wood to until the ball is embedded exactly 1/2 way, and
measuring the force required.
This test is essentially a "dent" test. It determines how difficult any wood is to dent, The
higher the force required, the harder it is to dent, and thus determines, in essence how
durable the wood would be for a martial arts weapon. There are other factors to consider
also, but in general, the harder to dent, the more durable.
The list of woods below contains the Janka hardness and weight of each wood I routinely
make into weapons. For comparison the Janka hardness of Oak is 1280, and weighs about
40 lbs per cubic foot. These numbers are compiled from many different sources, and
numbers vary slightly from tester to tester, but only slightly. I use mainly numbers, here,
from the Forest Services Laboratory, when I can. ( U.S. Govt funded). I have weighed the
woods I use and the weights are pretty darned accurate. And dojo testing confirms the
comparison in dent resistance. Please see my materials page for photos of these woods, or
google each for more pictures of each.
Padauk, Janka hardness of 1725, and weighs 48 lbs per cubic foot.
Bubinga, Janka hardness of 1980, and weighs 60 lbs per cubic foot.
Purpleheart, Janka hardness of 1860, and weighs 65 lbs per cubic foot.
Goncalo alves, Janka hardness of 2160, and weighs 50 lbs per cubic foot.
Mesquite, janka hardness or 2345, and weighs 50 lbs per cubic foot.
Brazilian rosewood, Janka hardness of 2440, and weighs 58 lbs per cubic foot.
Jatoba, Janka hardness of 2800, and weighs 55 lbs per cubic foot.
Bloodwood, Janka hardness of 2900, and weighs 63 lbs per cubic foot.
IPE, Janka hardness of 3680, and weighs 70 lbs per cubic foot.
Lignum Vitae, Janka hardness of 4500, and weighs about 80 lbs per cubic foot.
UHMWPE, a synthetic product, has no Janka hardness rating but is so dense that it does
just barely float in water.
As you can see there is little correlation between weight and hardness.
But think of it this way, IPE is three times harder to dent and almost twice as heavy as Oak
or Bloodwood is 2.5 times as hard to dent, and 1.5 time heavier than Oak, and so on.
There are other considerations like shear strength, bending strength, and a propensity to
splinter. These factors are best taken into account in Dojo testing, which I have done.
