Facts and nots : was Recommend Rebuilder?

[Farrell]

----- Original Message ----- 
> What I was thinking was, that if boards are glued together, then the 
> compression takes place. If some of those wood fibers compress, and form 
> the ridge, then the measurement, is less than if that portion had not 
> compressed more than the rest, so the crown would be less. Or is the crown 
> the same, because of the ribs, and the board just came in from the edges?

I think I understand your question. No, the board doesn't move in from 
anywhere. It is glued (presumably) to the ribs and stays put. Yes, you are 
correct thinking that the ridge, a product of crushed wood, is no longer 
under compression (or less so anyway) and that small segment of panel will 
support less crown. So yes, presumably the crown would be reduced.

But realize also that compression can damage wood cells outside of the ridge 
zone. Ridges formed on a panel suggest that the entire soundboard panel has 
been subject to some fair bit of compression, and presumably some amount of 
unseen wood cell damage (compression set). Likely crown has been reduced by 
some of that panel damage also.

Terry Farrell

BTW, after reading Ron N's response, I now realize what you were asking 
about "figuring out" the crown - you meant how do they calculate what to do 
during manufacturing to produce a desired amount of crown. I think Ron 
answered that question and your others quite eloquently.

> I hope someone, knows what I am trying to say, as I am having a problem 
> expressing myself. Obviously a field, I have not studied.
> John M. Ross