[pianotech] Downbearing on RC&S designs was RE: Steingraeber

[Dale Erwin]

Hey Gene
 No, because the compression is a dynamic force which the string bearing is compressing.  Ok, but...Yes, the ribs are being pushed to there previous flat state.  There are two counter opposing forces in this system albeit destructive as I see it. Not only that if you have ever done any pre-stressing of the board it gets stiffer and stiffer as its pushed downward.
 

 

Dale S. Erwin
www.Erwinspiano.com
209-577-8397

 

 

-----Original Message-----
From: Gene Nelson <nelsong at intune88.com>
To: pianotech at ptg.org
Sent: Mon, Jul 12, 2010 8:50 pm
Subject: Re: [pianotech] Downbearing on RC&S designs was RE:  Steingraeber


> If you have crown whether by design in the rib radius 
> or by compression, downbearing will increase the stiffness and as the 
> panel(s) move down there will be a movement in the direction of more 
> stiffness and as they move up there will a move in the direction of 
> looseness or less stiffness. 
 
Curious again - I have wondered about this. Is it not true that a CC board is likely at its maximum stiffness because of compression prior to applying the string load? String load pushes the board back toward it's at rest/nuteral (for lack of better term) position which should mean the board becomes less stiff under load?? 
Gene  

 
=
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