More on soundboard crown

[Richard Brekne]

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Hi Del, and thanks once again. I think I have enough to go on with for
now. Just trying to get a better handle on what happens when you do
this, or that... in my own way. I wasnt really trying to propose
anything, or resurect any dead horses. And I keep wanting to try and
find some rational for why so many seem to insist on the CC board. As
I've said .... its really difficult to simply accept the tradition and
marketing lines as complete explanations. Perhaps when I have the
benifit of deeper insights I will. I suppose my learning curve has a bit
different shape to it then maybe some are used to... but its mine and I
am stuck with it. I keep pluggin along as best I can. As far as
experimentation... actually I am just in the process of buying a small
hot box for fooling around with some of this. Probably try all sorts of
off the wall combinations... just to see what happens.

Anyways... thanks again.

RicB

Delwin D Fandrich wrote:

>
>      Hi Del... actually... I was rather thinking (again perhaps
>      another one of those bunny trails...) that perhaps one could
>      add about a 1/8th inch thick strip of left over sounboard
>      material to the top half of the rib, grain in the same
>      direction as the panels. If it was dried to say 6.5 MC prior
>      to attachment to the rib... and the soundboard was dried to
>      say 4.5 MC why wouldnt this tend to sort of buffer the ribs
>      cross grain constraint ? When taking on humidity this layer
>      would get slightly compressed by the rib... and since its
>      grain is in the same orientation of the panels it wouldnt
>      force that into nearly as much compression.... er.. I think
>      :)... If there was not enough crown you could rib crown
>      enough to make up the difference. I suppose you could rib
>      crown to begin with.. but if this provided a kind of solidly
>      glued  << slip joint >> , and if there was some good reason
>      to dry out the panel to 4.5 MC as long as one could avoid
>      exceeding the stress limits... well... Anyways.. I'm just
>      fooling with ideas in attempt to better sort out what does
>      and doesnt happen. yes ??
>
>      RicB
>
> I fail to see the point. Any time you dry a soundboard panel that far
> down there are going to be compression problems later on. Period.
> There is no way to "buffer" it. Unless, of course, you leave the panel
> free of constraints and let it float free. I.e., ribless and
> unattached. It is the MC in the panel--actually, the lack
> thereof--that is the problem. Since leaving the panel free and
> unattached is not a practical solution the simplest way to avoid the
> problem is to not dry them out that way.
>
> This is nothing I'm even remotely interested in working on. As you
> say, why not just crown the ribs? It's a simple and effective
> solution. It's a well known technology that has been around long
> enough that its working characteristics and advantages are fairly well
> known. And, by now, it's a technology that should be well accepted. Of
> course it is by many in the industry. And it would be by many more if
> it weren't for the monumental weight of tradition and design lethargy
> endemic to the industry. Personally I just don't see any reason to
> keep beating away at what I see as a dead horse. It's not going to
> come back to life--it's just going to keep right on being dead. The
> best you can do is tenderize the meat a little. Life, and most of the
> piano industry, moves on.
>
> As always, you're encouraged to design and construct an experiment.
> I'll not bother...I'm quite content with the rib crowning techniques
> I've worked on and refined over the years..
>
> Del

--
Richard Brekne
RPT, N.P.T.F.
UiB, Bergen, Norway
mailto:rbrekne@broadpark.no
http://home.broadpark.no/~rbrekne/ricmain.html
http://www.hf.uib.no/grieg/personer/cv_RB.html


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