So I recently finished two ukuleles following the Hana Lima 'Ia construction process, and now, with winter abruptly upon us, I have a cracked sound board. The sound board is old-growth douglas fir, with very tight growth rings, quarter sawn. I would describe it as splintery to begin with, which is likely a good bit of my problem. It cracked right where it joins to the tail block. Following the Hana lima 'Ia process, I installed the tail block with the grain running vertically front to back, i.e. perpendicular to the grain of the birds eye maple sides. The sides, being maple, which moves a lot with seasons, have shrunk, but the tail block did not, as it is sapele, and wood doesn't shrink lengthwise much anyway. As a result, the edges of the tail block are visible as a hump telegraphing through the sound board and the crack which runs to the bridge.

First question then: Is it the usual practice to orient the grain of the tail block vertically in spite of cross grain movement properties of the wood? If this were case work, I would not do it that way. Is there an acoustical or structural reason for doing it that way?

Second question: what would you luthiers suggest for corrective action?

My inclination is to try to remove the soundboard (yikes!) and replace it with a less splintery wood (probably birds eye maple or, perhaps, pau rosa). I am also tempted to chisel out the tail block and replace it with a piece of maple with the grain oriented parallel to that of the sound board and back.

I suspect that humidity is fairly constant in Hawaii (I read a comment that they can't use hide glue because it is too humid), but it varies wildly here in the Northeast, and I plan to travel with this thing a lot as well.

Thanks,

Nelson