Measure soundboard properties

Measure soundboard properties—As I mentioned in the design section, I like to keep records of the physical properties of the wood that goes into each guitar. Once the soundboard is roughly thicknessed, I measure its area and weight to determine the wood's density.

This fixture is where I measure the deflection caused by adding weights to the plate. This measurement combined with the density measurement allows me to calculate Young's modulus of elasticity (E). I calculate E with the grain, across the grain, and I make a composite measurement using the deflection when held by a circular support (conveniently located on the other side of the fixture).

Once I know E, I thin the soundboard close to a final thickness. I make these same measurements on the backs.