[pianotech] Bridge agraffes FYI

[Encore Pianos]

Looking at the photos sent with your first post on this subject, they were
clear enough to see that the maple surface of the bridge in your photograph
were in what looked to be pretty good shape compared to what I have seen.  I
see deep crush marks around the string impressions on my customers pianos,
particularly near the edge of the step to the agraffe where it loses further
support.  I think you are underestimating how much the wood has  visibly
given way to the string pressure in the pianos I have seen that are
particularly false.  You may be surprised, but I am not.  I'm not inclined
to believe that the problem lies with the agraffes or at the capo bar, given
that the falseness is so widely distributed and extends down into the area
where there are agraffes at the front as well.  

This falseness is exhibited in almost every note throughout the area of the
bridge where the agraffes are used, to a greater or lesser degree.  It is
the kind of sound you get when the string energy is bleeding past a
termination - not a buzzing but strong false beats of varying beat rates,
and it will vary from note to note in beat speed and intensity.    

Also, your bridge looks slightly different than what I have seen.  My
customers pianos have the area where the flat top of the bridge angles down
to the agraffe in a more rounded configuration, rather than what appears to
be an angled flat surface in your photograph.  

Agraffe deterioration?  I suppose it is possible, but what about this design
would cause widespread wear of the agraffe?  The deflection angle does not
appear to be any greater than we see between agraffe and string rest at the
other end of the speaking length.  

Will

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of David Love
Sent: Thursday, October 25, 2012 8:07 PM
To: pianotech at ptg.org
Subject: Re: [pianotech] Bridge agraffes FYI

I would be surprised if the area behind the aggraffe (hitch pin side) was
the source of falseness.  Unless the aggraffe itself had deteriorated (which
it well might have) I don't think any small angle change resulting from some
crushed wood would be the source of poor termination.  The capo section
might well be a source (see attached photo).  

David Love
www.davidlovepianos.com


-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Encore Pianos
Sent: Thursday, October 25, 2012 4:20 PM
To: pianotech at ptg.org
Subject: Re: [pianotech] Bridge agraffes FYI

I have a couple of these in my service presently here in New Hampshire, and
have had others in the past.  

These bridges probably sounded pretty good in 1925 when they were new, but
as they age, they can become insanely, incredibly false.  This I would
attribute to the deterioration of the bearing surface of the maple just
behind the agraffe where the string presses into it.  The strings literally
crush the surface reducing the angle of deflection of the string as it exits
the back of the agraffe, and an insecure termination and the falseness is
the result.  I have heard these problems on a number of these agraffed
sohmers, mostly the (stupid) cupid grands.  So I attribute that to a flaw of
the design rather than an isolated incident.

Living in New England, I am in a harsh environment for pianos with dry
winters and humid summers, so perhaps I see more deterioration than you do,
in your more benign environment.  

Will Truitt