Rib Tapering

Richard Brekne Richard.Brekne@grieg.uib.no
Fri, 23 Jan 2004 16:18:31 +0100


Ok soundboard makers of the nett... Question.

I have re-ribbed this old square grand soundboard, and used more or less 
the ideas Joe and I exchanged, and I am ready to finish off the ribs 
now. On most of these oldies the ribs are very gradually thinned from 
the middle to the edges of the board. On newer instrument types the ribs 
are the same thickness  for most of the width of the panel, then tapered 
suddenly.

So... what is the functional difference and what would be the 
recommended type of tapering for this case. It is a very low tension 
affair and probably will not be able to exert so very much down bearing 
if that means anything.  If I had to hazard a guess I'd wonder about how 
tapering effects the flexibility at the edges. But thats just guessing.

First time out with a soundboard rebuild.... finally have my fingernails 
a bit dirty with this kind of work. So any good advice is muchly 
appreciated. The panel was dried for 2 weeks in my shop to the lowest RH 
we get in these parts... roughly 26 %. The panel is about half the 
thickness of a modern panel, and the ribs in question are about 1 cm 
thickness, 2 cm wide, and 2 of them are 60 cm long the third about 45. I 
can post a picture if that would be of help.

Thanks muchly

RicB


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