The Hub

For my current mandolin build, I set out to answer 2 questions:

1. Whether to use physical deflection or frequency analysis to measure stiffness, and

2. How well can I measure wood quality in rough sawn form? (T. Gore says it needs to be planed smooth and rectangular for frequency analysis.)

I have 4 different topwood species available for my current build: California Sitka, Englemann, Lutz, and Coastal Redwood. The billets range from 378 for the lightest piece of Englemann to 480 kg/m3 for the heaviest Sitka (in many aspects this sitka is in the realm of red spruce). All samples were acclimatized at 45% RH for several months before testing. I used rectangular pieces roughly 400 mm x 140 mm x 20 mm. For deflection, I used a 50 lb mass over a 350 mm span and for frequency analysis I used REW and the method described in Giuliano Nicoletti’s book.