Episode 35 MOR/MOE Lumber Properties

MOR Lumber Test

Modulus of Rupture is also known as Bending Strength.  The MOR lumber test tells us how much force is required to snap a board of a particular species.  It is particularly helpful when building something that will experience dynamic loads or more obviously when actually bending the wood into a specific shape.

MOE Lumber Test

Modulus of Elasticity, also known as Stiffness tells us how much force it takes to bend a species to a specific deformation.  Imagine setting a board on two fixed points and then pushing in the middle between those points.  How much force does it take to bend the middle of that board down to 2" or 3"?  This is the MOE number.  The higher the number the stiffer the species and the less it will sag under load.  Or the more force it can exert when it snaps back from bent to straight.

Both of these properties tell us a lot about how strong a species is in use.  The MOR lumber tests and the MOE test are all about the strength of a wood species.  They also highlight some of those unique species out there like Hickory or Osage Orange that over the centuries have developed into specific use like tool handles and bows.