not quite 'factory'?

[Bill Ballard]

On 9/4/97 12:22 PM, Guy, Karen, and Tor Nichols <nicho@lascruces.com> 
wrote:

>On TOP of the central belly beam, directly under the tenor bridge, about
>where notes 36 thru 40 cross the bridge, is a collection of hardware that
>just doesn't look like factory installation. The pile consists of a nut (or
>bolt head)and washer on the beam, with a washer-type thing on top, and a
>heavy coiled spring bridging the remaining gap to the bottom of the board,
>where it seems to push up on the board (with a BIG flat washer), right
>under the bridge. 


I put one of these in a square grand I was rebuilding back in '78, and 
there was a PTJ article on it earlier that year. Apparently, the idea is 
that if the soundboard has lost some of its resilience/resonance, the 
coil spring coupled to it can make up for that loss. How the springiness 
of the steel coil integrates with the way sound vibrates the larger 
spruce panel, I don't know. It always seemed to a a truss belt for a 
piano which had lost its "abdominal muscle tone".

Bill Ballard, RPT
New Hampshire Chapter, PTG

"When writing a mental note, first procure a mental piece of paper"
............mental graffitti