Counterbearing angle

David Love davidlovepianos@hotmail.com
Sat, 17 Mar 2001 04:45:09 -0000


Paul:

I've often run into problems on Steinways with buzzing through the agraffes 
(even new ones) in different places in the piano.  Most recently on a D this 
problem occurred in several places in the tenor and just below the bass 
break (not a string winding buzz).  I have also run into problems with clean 
intonation on note 53 (last agraffe) and leakage throught the capo section 
is a constant battle.  I have in the past remedied problems in the agraffe 
section by increasing the counterbearing angle by adding a brass semi round 
between the tuning pin and the agraffe.  I have often considered when 
restringing to build up the string-rest felt as a prophylactic measure.  In 
the capo section sometimes the problem is the shaping of the v-bar itself 
which can be remedied.  But again, I have often wondered whether or not the 
tone/power might not be improved by building up the cast duplex.  A hollowed 
out half-round of brass could be fitted over the cast duplex, or if the 
duplex needs to be detuned, it could be placed in a different position.  My 
questions are:  Is there an optimum amount of counterbearing?  Is there a 
recommended way of building it up in the capo section when dealing with a 
cast duplex as in a Steinway?  What are the downsides to building up the 
counterbearing, if any?  And any other questions which I either haven't 
asked or haven't thought of.  I would be interested to hear what you think.

David Love

>From: Yardarm103669107@AOL.COM
>Reply-To: pianotech@ptg.org
>To: pianotech@ptg.org
>Subject: Re: Counterberaing angle
>Date: Fri, 16 Mar 2001 20:49:09 EST
>
>David:
>I've done a good bit of research on this over the years, and yes, many 
>pianos
>need reassessment. The relationships between the angle, shape of capo,
>friction/upbearing forces, tension between segments, etc. are all
>interrelated and very complex. The same principles hold true for the other
>end as well. What explicitly have you run into that leads you to this
>question?
>PR-J

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