Recrowning the soundboard,something different

[Farrell]

Jim wrote:
>  Pressure on the soundboard is directly related to downbearing and can range 
> from 0 pounds to ?????....... 

Small correction Jim. You must not see the same pianos I do! Pressures can range from something significantly less than zero!

Terry Farrell
  
----- Original Message ----- 
From: <JIMRPT@AOL.COM>
To: <pianotech@ptg.org>
Sent: Saturday, May 25, 2002 8:19 AM
Subject: Re: Recrowning the soundboard,something different


> 
> In a message dated 25/05/02 8:06:26 AM, wayne.hohle@sympatico.ca writes:
> 
> << p.s. is there really  20 tons of pressure on the soundboard or is that on 
> the
> frame and the pressure at downbearing at the bridge is something different
>  >>
> 
> Wayne;
>  No there is not 20 tons of pressure on the soundboard. The 18/20 ton figure 
> is from the tension on the plate.  With 250 (aprox) pins, each with a string 
> tension of aprox 180 lbs, you would arrive at aprox 22.5 tons of tension on 
> the plate.
> 
>  Pressure on the soundboard is directly related to downbearing and can range 
> from 0 pounds to ?????....... for the sake of calculation let's say that 
> downbearing on a brand X thingee was 4 lbs per string...OK then @ 250 strings 
> that would be 1,000 lbs of pressure on the board.
>  A board under 20 tons of pressure would self destruct immediately if not 
> sooner and totally without regard to crowning method used.. ;-)
>  Jim Bryant (FL)