Thicknessing a joined top

[ScottC.]

Hey, I bought a couple of these Martin seconds kits to fool around with and the tops are already joined and cut to shape pretty much, is there a good way to determine a target thickness for these?
Thanks, Scott

[Trevor Gore]

Scott, in a word, No!

Your best bet, though, is to try to get a value for Elong using a static deflection test. Use a short span in the lower bout where the width is fairly constant, e.g. 50mm or so either side of the maximum lower bout width. You then have a span of ~100mm which you can load up with a bar (like this: down at the bottom of the page) and measure the deflection and then work out Elong. All the equations are in the book. Then use generic values for Ecross and G and plug all those numbers into the plate thickness formula. That should get you a thickness number which is near enough to the right ball park to pull it in to target with a combination of edge thinning, bridge mass selection and side masses.

[ScottC.]

Thanks Trevor, I may cut the tops where they joined and do the standard testing. That's an interesting link!
Scott