Official Luthiers Forum!

There's no doubt that the structure is stronger if the UTB is pocketed into the sides and is firmly supported in all degrees of freedom. As for the brace itself, the thicker the brace is, the stronger it is. I think the real question - as some have alluded to - is how strong does it really need to be?

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http://www.PeakeGuitars.com

Don't forget the other functions of the UTB
Besides resisting movement perpendicular to the soundboard, it is also a major player in distributing force around the soundhole.
One detail that I see on some makeys UTB's that concerns me is a large hole for truss rod adjustment, coupled with aggressive rounding of the profile which can leave only a small sliver of wood at the inner face.

Thanks to Todd for his elegant and lucid explanation of the various terms... stresses/strains/stiffness/strength etc...

Like I said earlier , I am just an old carpenter with antediluvian intuitive assessments of where the stresses and strains occur in any structure ....floors...roofs...guitars ...it's all one to me.

Which brings me to another question (which is in fact related to the UTB issue)

Some builders ( Rick Turner being perhaps the most notable example) use CF rods or tubes at the neck block to create a triangulation to counteract the deforming stress caused by the string tension.

Now, as far as I am aware, (and I may be wrong here, and am open to correction) these Cf reinforcements always run from the top of the neck block to the brace on the back, (the one underneath the soundhole)

My question here is ...(and is stimulated by my experience of having made dozens if not hundreds of ledged and braced wooden gates)..would it not be a more efficient construction if the CF tubes/rods were to be anchored on the base of the neck block, and angled upwards to rest in the ends of the UTB ?

EDIT: I should have done a Google search earlier, but I see that Kent Chasson has implemented exactly what I am talking about ..no doubt he will stop by and comment ...

Or even better if you used some bracing from the top of the neck block, fixed to the soundboard and running around the soundhole towards the bridge................like a martin A brace or functional equivalent