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<DIV><FONT face=Arial size=2>If we have to go back to the times of =
poor bushing
cloth...yes that is a factor. I'm not even sure poor quality =
bushing
cloth can be bought anymore? Don, with all your expertice, =
if you
have a preference in bushing cloth and have reservations about some on =
the
market...PLEASE let me know...privately if need be. =
</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>David Ilvedson</FONT></DIV>
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style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>
<A title=donmannino@comcast.net =
href="mailto:donmannino@comcast.net">Don
Mannino</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A =
title=pianotech@ptg.org
href="mailto:pianotech@ptg.org">Pianotech</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Wednesday, August 25, =
2004 7:11
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Pinning on new =
flanges</DIV>
<DIV><BR></DIV>At 01:38 PM 8/25/2004, you wrote:<BR>
<BLOCKQUOTE class=cite cite="" type="cite"><FONT face=arial =
size=2>If you
have a hammer swinging 4 to 7 times and it has side play you have a =
birdseye
problem...not the bushing.<BR></FONT> <BR><FONT face=arial =
size=2>David
I.</BLOCKQUOTE><BR>Well, David, there is also the quality (or lack =
thereof) of
the bushing cloth.<BR><BR>As many here know, I have done a bit of =
study into
action centers, especially grand hammer centers, both on my own and =
through
work with a company I worked for in the past. Even and 'correct' =
friction
became an obsession when I was rebuilding pianos during the =
80s.<BR><BR>At
that time a piano dealer I did work for was having me "maximize" a =
certain
brand of American pianos, which at the time was using seriously =
substandard
action cloth and / or cloth sizing procedures. One of the steps =
I took
in customizing these actions was to do a very heavy shrink-fitting of =
the
hammer shank centers. Short of rebushing the shanks, this was =
the best
way I found to improve the fit of the centers. The centers =
(which came
with 19.5 pins as I recall) became extremely loose, after which I =
burnished
and fitted 20.5 pins into the now thinner bushings.<BR><BR>The change =
in touch
and tone from this one change to the piano was incredible. It =
was not
subtle at all - the pianos sounded dramatically more solid in tone and =
more
powerful. Of course, I had to re-weigh off the keyboards, as the =
weights
had been installed with horribly uneven friction levels in the =
actions.
Hammer flange friction varied from 2 to 10 grams in almost every set I =
worked
on.<BR><BR>The bushing quality is the big variable in fitting action =
centers,
and is one reason people will disagree so strongly on what friction is =
correct. Their experience with different pianos causes different =
opinions to be developed.<BR><BR>When repinning hammer centers, I have =
always
pinned for even friction through the set. I strive for +- 1/2 =
gram
within a set (a 1 gram tolerance - which I would prefer to be 0, of =
course),
and the amount of friction is decided on according to the ambient =
temperature
and humidity, and the relative firmness of the action center =
cloth. 4 -
6 grams is a guideline, but I frequently pin parts with very high =
quality felt
at 2 grams, especially in dry conditions.<BR><BR>If the cloth is firm, =
it can
be pinned more loosely and still control the hammer motion well. =
If the
cloth is soft, you must pin it tighter in order to maintain the =
control.
I do not have a formula to decide how tight - it comes from feeling =
the side
play after pinning, and the experience of checking this on many
pianos.<BR><BR>As for tonal change from very tight centers, the best
illustration I have had was with one unfortunate piano in which the =
hammer
centers were all gummed up. The usual problem of the owner not =
wanting
to pay for new parts was there, so with a written disclaimer signed by =
the
customer, I agreed to clean and lube the action to keep it working =
until the
parts could be replaced. The tonal change was absolutely =
dramatic - the
customer said afterwards "I didn't know you were going to make the =
tone
better, too!" With sluggish centers the tone was dull and =
muffled with
very, very poor sustain. After freeing up the centers the tone =
was
moderately bright with very good sustain.<BR><BR>I am also fond of the =
later
version of the Teflon bushings, by the way, but this is long enough =
for
now.<BR><BR>Don Mannino RPT<BR></FONT><BR></BLOCKQUOTE></BODY></HTML>