[CAUT] Gravalla Tension regulator

[Ron Nossaman]

> The piece that is in there is intended to stiffen the belly rail, and it
> works. My understanding is that it is under tension as opposed to
> compression. It's pulled end to end as it holds the bell rail from pushing
> out under the down bearing on the board. If you picture that it's easier to
> understand it's size than if your thinking compression like the beams.

The belly rail won't push out from downbearing load. If 
anything, it'll pull in. Soundboard crown isn't an arch. See 
April 2006 Journal, "Rib crown as an End-Buttressed Arch".

Ron N