Shopping for a Belly

[Farrell]

Sounds like you've got your thinking cap on Bill! You are heading toward my BIG question:

You need to replace the soundboard in piano X. We either know it originally had a compression crowned board or we simply do not know about the original crowning method. But we know we want a rib crowned board.

So what do we do. Most folks will either make a new board themselves by copying the original dimensions or perhaps they will order a "board in a box" from one of several sources. These also will be "copies" of the original board dimensions (panel thickness, rib cross sections, rib array). To the best of my knowledge at least several (if not all) of these "board in a box" sources rib crown (at least partially) their boards.

Now I'm no soundboard designer, but it seems plain as day to me that as soon as you cut a radius into those ribs, you are changing the design of the soundboard. You are changing the load capacity of those ribs. The amount of panel compression should also affect things. If the ribs can support more load, maybe we want smaller ribs. Maybe we want a thinner panel. Maybe, maybe, maybe. Who knows? Yet we are maintaining the original rib dimensions. Is it just done that way because we don't know what else to do?

It seems to me this approach is a shot in the dark. Perhaps with a few pianos, such as Steinways and Mason & Hamlins, this approach has been tried enough times and one can have some reasonable expectations about the results. But what happens when you replace the board in an old Weber, or an old Decker Bros., or an old A. B. Chase or many others? Take a shot in the dark?

Someday, if my soundboard building thing smoothes out, I would really like to start providing some belly services to other local techs/rebuilders who do not do soundboards. Great! But I know someone (likely with a Steinway) will tell me that they don't want to change the belly design - just reproduce the original. Well, I can't for the life of me imagine building a compression-crowned board (I won't do it!). And I'm not going to just reproduce the original dimensions and arbitrarily crown the ribs - who knows what will result. So what does one do in this case?

That leads me to another thing that bugs me. (Like you really want to hear this?) I have run across several apparently highly respected, obviously very skilled, very experienced, etc., etc., rebuilders who go to great lengths to "reproduce the original piano exactly". They don't even want to rescale the darn thing (not picking on anyone in particular - I have heard this philosophy many times). But, they go right ahead and replace the original compression crowned soundboard with a rib crowned soundboard. They change the very heart of the piano. I don't get it.

I'll go to bed now. Grrrrrrrrrrr.   ;-)

Terry Farrell
  
----- Original Message ----- 
From: "Bill Ballard" <yardbird@vermontel.net>
To: <pianotech@ptg.org>
Sent: Tuesday, April 22, 2003 9:29 PM
Subject: Shopping for a Belly


> So if I wanted to look locally for a soundboard installer doing it as 
> somebody halfway, all the way across the country would, my two 
> questions in the survey would be 1.) do you put a crown in your ribs 
> and if so, what % of belly press crown, and 2.) what's your working 
> E.M.C. during the process. And the answer I would want to hear would 
> be 1.) yes and 100% of crown (ie., the ribs don't get bent in the 
> press), and 2.) no lower than 6% E.M.C. All other things being equal 
> (known workmanship and reputation, proper I.N.S. documentation for 
> the employees, etc.).
> 
> Would this indicate a belly put together as Ron and Del have been 
> describing it? Or should I add another question or two?
> 
> Bill Ballard RPT
> NH Chapter, P.T.G.
> 
> "There are fifty ways to screw up on this job. If you can think of 
> twenty of them, you're a genius......and you aint no genius"
>      ...........Mickey Rourke to William Hurt, in "Body Heat", discussing arson.
> +++++++++++++++++++++
> _______________________________________________
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