Rolled bridge: cause? diagnosis? treatment? Or maybe a floating pinblock?

J Patrick Draine draine@mediaone.net
Wed, 13 Jun 2001 08:34:44 -0400


>
>
>Does this sound like a rolled bridge? How is a rolled bridge caused? 
>Is there an accurate way to diagnose a rolled bridge? Can it be 
>fixed in the field?
>

Dear List,
Am I correct in my observation that the learned discussions of killer 
octaves, soundboard stiffness, soundboard crown, and downbearing 
seldom (if ever) refer to "rolled bridges"? I.e. that it's not a 
matter of bridges wandering, but rather collapse (lack of stiffness) 
of the soundboard in the desired areas.

I've never felt comfortable with discussions of "rolled bridges", 
especially when it came to advice to *not* raise pitch to A440 on an 
older piano out of a fear of rolling.

At any rate, I'd be pleased to have this clarified by the Enlightened 
Ones (Del, Ron, et al).

 From this non-rebuilder's perspective, Tom, it sounds like it's time 
to send that piano to a better shop, for a new board!

Best wishes,
Patrick Draine

PS The write up for Del Fandrich's class "Designing and 
Remanufacturing the Small Piano" states that "Much of the material 
covered appears in the instructor's book of the same name." Is there 
an upcoming  publication date?


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