Compression ridges was :Do you dry the ribs, along with the board, prior to gluing ?

[Greg Newell]

Clark,
	I'm no scientist either but it seems to me that what you are seeking
is certainly designable (is that a word?) in the dimension and layout of the
ribset. This, of course, would include how many ribs you plan to use. It
seems that at times you can fall short a bit on the mass side since you have
limitations regarding the spruce material you're working with. This is
probably why the brass weights screwed to the underside of the bridge are
used. Other than that it seems to me that while both mass and stiffness are
present at both ends of the board the alternate one is favored over the
other at opposite ends of the board. Does this make sense? Anyone?  

Greg Newell
Greg's Piano Forté
www.gregspianoforte.com
216-226-3791 (office)
216-470-8634 (mobile)

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Clark Sprague
Sent: Saturday, February 02, 2008 9:02 AM
To: Pianotech List
Subject: Re: Compression ridges was :Do you dry the ribs, along with the
board, prior to gluing ?

    I have been following this exchange about soundboards very intently, as 
one who wants to start building them.  Which brings me to a question.  I was

tuning a Yamaha GA-1 grand the other day, which is famous for having a 
terrible bass-tenor break.   I made a comment to Del at one time about how I

thought that the board in these small grands was maybe too flexible at the 
lower end, as they go out of tune so much there with humidity changes, and 
he said to me that most people complain that the board is too stiff there, 
on these pianos.  I seem to remember a while back that David Love (I could 
be wrong) posted something about adding mass to the tenor end of the long 
bridge on an M, and how that made the tone so much better.  I am no 
scientist, but I wonder, as I bet many others do about this stiffness and 
mass question.  More stiff, less stiff, more or less mass, the effects of 
these, and how does one "design" these into a board one is contemplating 
building?  How do they interact?  What effects do these have on tuning 
stability, tone, etc.
    I hope I haven't attributed past posts to the wrong people,  just 
questioning how this all fits together.  Recommended reading, just 
experience, or what?  Does adding weight to the bottom of the bridge just 
add mass, or somehow decrease in increase stiffness,  I'm so confused.
Clark A. Sprague, RPT

----- Original Message ----- 
From: "Richard Brekne" <ricb at pianostemmer.no>
To: <pianotech at ptg.org>
Sent: Saturday, February 02, 2008 5:15 AM
Subject: Compression ridges was :Do you dry the ribs, along with the 
board,prior to gluing ?


> Hi Dean..
>
> .  But I also understand Del to mean that that stiffness to mass ratio in 
> bass is lower and in the treble is higher...  :)
>
> Cheers
> RicB
>
>
>
>    Ric,
> except you are adding that there is a minimum
>    threshold of
>    mass desirable for the bass and a minimum threshold of stiffness
>    desirable
>    for the treble. I would just like to explore what those minimum
>    thresholds
>    are.
>
>    You are saying stiffness is more important in the bass and mass is more
>    important in the treble. By inference then mass is less important in 
> the
>    bass and stiffness less important in the treble. That is basically
>    the same
>    thing I remember Del saying.
>
>    Dean
>
>    Dean May             cell 812.239.3359
>
>    PianoRebuilders.com   812.235.5272
>
>    Terre Haute IN  47802
>