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<body bgcolor=white lang=FR link=blue vlink=blue =
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<div class=Section1>
<p class=MsoNormal><span class=StyleCourrierlectronique23><font =
size=2
color=navy face=Arial><span lang=DE =
style='font-size:10.0pt;mso-bidi-font-size:
12.0pt;font-family:Arial;mso-ansi-language:DE'>Berhard, Don, =
Sarah,<o:p></o:p></span></font></span></p>
<p class=MsoNormal><span class=StyleCourrierlectronique23><font =
size=2
color=navy face=Arial><span lang=DE =
style='font-size:10.0pt;mso-bidi-font-size:
12.0pt;font-family:Arial;mso-ansi-language:DE'><![if =
!supportEmptyParas]> <![endif]><o:p></o:p></span></font></span></p>
<p class=MsoNormal><span class=StyleCourrierlectronique23><font =
size=2
color=navy face=Arial><span lang=EN-GB =
style='font-size:10.0pt;mso-bidi-font-size:
12.0pt;font-family:Arial;mso-ansi-language:EN-GB'>Would a somewhat =
flexible
support on the pivot side help in absorbing some oscillation ? =
I’ve seen
strange results when the underside of the hammer flange is cut in an =
arch shape
(the shape of Steinway flange).<o:p></o:p></span></font></span></p>
<p class=MsoNormal><span class=StyleCourrierlectronique23><font =
size=2
color=navy face=Arial><span lang=EN-GB =
style='font-size:10.0pt;mso-bidi-font-size:
12.0pt;font-family:Arial;mso-ansi-language:EN-GB'><![if =
!supportEmptyParas]> <![endif]><o:p></o:p></span></font></span></p>
<p class=MsoNormal><span class=StyleCourrierlectronique23><font =
size=2
color=navy face=Arial><span lang=EN-GB =
style='font-size:10.0pt;mso-bidi-font-size:
12.0pt;font-family:Arial;mso-ansi-language:EN-GB'>The first idea was =
that it
helps decoupling between hammer/shank and the rest of the action, so the =
system
being more free, more energy is =
transmitted.<o:p></o:p></span></font></span></p>
<p class=MsoNormal><span class=StyleCourrierlectronique23><font =
size=2
color=navy face=Arial><span lang=EN-GB =
style='font-size:10.0pt;mso-bidi-font-size:
12.0pt;font-family:Arial;mso-ansi-language:EN-GB'><![if =
!supportEmptyParas]> <![endif]><o:p></o:p></span></font></span></p>
<p class=MsoNormal><span class=StyleCourrierlectronique23><font =
size=2
color=navy face=Arial><span lang=EN-GB =
style='font-size:10.0pt;mso-bidi-font-size:
12.0pt;font-family:Arial;mso-ansi-language:EN-GB'>Easy experiment and =
immediate
result – unfortunately, one can’t tighten the flange screw =
with enough force
(and without changing the pivot position =
.<o:p></o:p></span></font></span></p>
<p class=MsoNormal><span class=StyleCourrierlectronique23><font =
size=2
color=navy face=Arial><span lang=EN-GB =
style='font-size:10.0pt;mso-bidi-font-size:
12.0pt;font-family:Arial;mso-ansi-language:EN-GB'><![if =
!supportEmptyParas]> <![endif]><o:p></o:p></span></font></span></p>
<p class=MsoNormal><span class=StyleCourrierlectronique23><font =
size=2
color=navy face=Arial><span lang=EN-GB =
style='font-size:10.0pt;mso-bidi-font-size:
12.0pt;font-family:Arial;mso-ansi-language:EN-GB'>I like also to =
understand
what is the role of shank flexion in tone dynamic (or expressiveness) =
seem to
me that the shanks are flexing easily with the hammer acceleration, I =
don’t see
them like a very rigid support.<o:p></o:p></span></font></span></p>
<p class=MsoNormal><span class=StyleCourrierlectronique23><font =
size=2
color=navy face=Arial><span lang=EN-GB =
style='font-size:10.0pt;mso-bidi-font-size:
12.0pt;font-family:Arial;mso-ansi-language:EN-GB'>When checking for =
rubbing hammer
tails, most shanks are flexing a little without so much pressure on the =
head.<o:p></o:p></span></font></span></p>
<p class=MsoNormal><span class=StyleCourrierlectronique23><font =
size=2
color=navy face=Arial><span lang=EN-GB =
style='font-size:10.0pt;mso-bidi-font-size:
12.0pt;font-family:Arial;mso-ansi-language:EN-GB'><![if =
!supportEmptyParas]> <![endif]><o:p></o:p></span></font></span></p>
<p class=MsoNormal><span class=StyleCourrierlectronique23><font =
size=2
color=navy face=Arial><span lang=EN-GB =
style='font-size:10.0pt;mso-bidi-font-size:
12.0pt;font-family:Arial;mso-ansi-language:EN-GB'>Indeed lighter hammers =
seem
to be more responsive to acceleration, but may be harder to control, too =
much “free
energy” as you said Berhard, vs a heavier hammer (or one that is =
glued farther
on the shank ?) that send a lot of feedback to the pianist thru action
compression, then work more slowly for tone production (may be giving =
more the
impression of control, up to some point =
nowadays)<o:p></o:p></span></font></span></p>
<p class=MsoNormal><span class=StyleCourrierlectronique23><font =
size=2
color=navy face=Arial><span lang=EN-GB =
style='font-size:10.0pt;mso-bidi-font-size:
12.0pt;font-family:Arial;mso-ansi-language:EN-GB'><![if =
!supportEmptyParas]> <![endif]><o:p></o:p></span></font></span></p>
<p class=MsoNormal><span class=StyleCourrierlectronique23><font =
size=2
color=navy face=Arial><span lang=EN-GB =
style='font-size:10.0pt;mso-bidi-font-size:
12.0pt;font-family:Arial;mso-ansi-language:EN-GB'>But may be that is a =
totally different
subject in the end …<o:p></o:p></span></font></span></p>
<p class=MsoNormal><span class=StyleCourrierlectronique23><font =
size=2
color=navy face=Arial><span lang=EN-GB =
style='font-size:10.0pt;mso-bidi-font-size:
12.0pt;font-family:Arial;mso-ansi-language:EN-GB'><![if =
!supportEmptyParas]> <![endif]><o:p></o:p></span></font></span></p>
<p class=MsoNormal><span class=StyleCourrierlectronique23><font =
size=2
color=navy face=Arial><span lang=EN-GB =
style='font-size:10.0pt;mso-bidi-font-size:
12.0pt;font-family:Arial;mso-ansi-language:EN-GB'>Best =
regards.<o:p></o:p></span></font></span></p>
<p class=MsoNormal><span class=StyleCourrierlectronique23><font =
size=2
color=navy face=Arial><span lang=EN-GB =
style='font-size:10.0pt;mso-bidi-font-size:
12.0pt;font-family:Arial;mso-ansi-language:EN-GB'><![if =
!supportEmptyParas]> <![endif]><o:p></o:p></span></font></span></p>
<p class=MsoNormal><span class=StyleCourrierlectronique23><font =
size=2
color=navy face=Arial><span lang=EN-GB =
style='font-size:10.0pt;mso-bidi-font-size:
12.0pt;font-family:Arial;mso-ansi-language:EN-GB'>Isaac =
OLEG<o:p></o:p></span></font></span></p>
<p class=MsoNormal><span class=StyleCourrierlectronique23><font =
size=2
color=navy face=Arial><span lang=EN-GB =
style='font-size:10.0pt;mso-bidi-font-size:
12.0pt;font-family:Arial;mso-ansi-language:EN-GB'><![if =
!supportEmptyParas]> <![endif]><o:p></o:p></span></font></span></p>
<p class=MsoNormal><span class=StyleCourrierlectronique23><font =
size=2
color=navy face=Arial><span lang=EN-GB =
style='font-size:10.0pt;mso-bidi-font-size:
12.0pt;font-family:Arial;mso-ansi-language:EN-GB'><![if =
!supportEmptyParas]> <![endif]><o:p></o:p></span></font></span></p>
<p class=MsoNormal><span class=StyleCourrierlectronique23><font =
size=2
color=navy face=Arial><span lang=EN-GB =
style='font-size:10.0pt;mso-bidi-font-size:
12.0pt;font-family:Arial;mso-ansi-language:EN-GB'><![if =
!supportEmptyParas]> <![endif]><o:p></o:p></span></font></span></p>
<p class=MsoNormal><font size=2 color=black face=Tahoma><span =
style='font-size:
10.0pt;font-family:Tahoma;color:black'>-----Message d'origine-----<br>
<b><span style='font-weight:bold'>De :</span></b>
pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org]<b><span
style='font-weight:bold'>De la part de</span></b> Bernhard Stopper<br>
<b><span style='font-weight:bold'>Envoyé :</span></b> vendredi =
19 décembre
2003 01:02<br>
<b><span style='font-weight:bold'>À :</span></b> Pianotech<br>
<b><span style='font-weight:bold'>Objet :</span></b> Re: Cockeyed =
hammers
/ Don Gilmore</span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'><![if =
!supportEmptyParas]> <![endif]><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span =
lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:black;mso-ansi-language=
:EN-GB'>Don/Sarah,</span></font><font
color=black><span lang=EN-GB =
style='color:black;mso-color-alt:windowtext;
mso-ansi-language:EN-GB'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New =
Roman"><span
lang=EN-GB =
style='font-size:12.0pt;color:black;mso-ansi-language:EN-GB'> </sp=
an></font><font
color=black><span lang=EN-GB =
style='color:black;mso-color-alt:windowtext;
mso-ansi-language:EN-GB'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span =
lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:black;mso-ansi-language=
:EN-GB'>To
design a hammer so that its pivot coincides with the center of =
percussion
is THE way to get a free sound and the maximum of energy transfer to the
string. it also allows the hammer to reject the fastest way possible
because oscillations in the pivot produce friction and slow
down hammer movement at contact point. </span></font><font =
color=black><span
lang=EN-GB =
style='color:black;mso-color-alt:windowtext;mso-ansi-language:EN-GB'><o=
:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span =
lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:black;mso-ansi-language=
:EN-GB'>i
did several simulations with software called pro/mechanica and reshaped =
hammers
after results found. one could say that actual hammer with heavy felts =
have
their center of percussion much far away from the pivot than lighter =
hammers
have. putting a small lead in the tail of the hammer can make them come =
closer
to that point. center of hammer mass should ly on a line along the =
center
of the hammer shank and the center of percussion is at =
distance x
from pivot that can be calulated by the formula x=I/(m*y) with I= =
moment of
inertia, m=mass, y=distance to center of mass</span></font><font =
color=black><span
lang=EN-GB =
style='color:black;mso-color-alt:windowtext;mso-ansi-language:EN-GB'><o=
:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New =
Roman"><span
lang=EN-GB =
style='font-size:12.0pt;color:black;mso-ansi-language:EN-GB'> </sp=
an></font><font
color=black><span lang=EN-GB =
style='color:black;mso-color-alt:windowtext;
mso-ansi-language:EN-GB'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span =
lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:black;mso-ansi-language=
:EN-GB'>regards,</span></font><font
color=black><span lang=EN-GB =
style='color:black;mso-color-alt:windowtext;
mso-ansi-language:EN-GB'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New =
Roman"><span
lang=EN-GB =
style='font-size:12.0pt;color:black;mso-ansi-language:EN-GB'> </sp=
an></font><font
color=black><span lang=EN-GB =
style='color:black;mso-color-alt:windowtext;
mso-ansi-language:EN-GB'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span =
lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:black;mso-ansi-language=
:EN-GB'>Bernhard</span></font><font
color=black><span lang=EN-GB =
style='color:black;mso-color-alt:windowtext;
mso-ansi-language:EN-GB'><o:p></o:p></span></font></p>
<div style='border:none;border-left:solid black 1.5pt;padding:0cm 0cm =
0cm 4.0pt'>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:3.75pt;border:none;mso-border-left-alt:solid black 1.5pt;
padding:0cm;mso-padding-alt:0cm 0cm 0cm 4.0pt'><font size=2 =
color=black
face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:Arial;
color:black;mso-ansi-language:EN-GB'>----- Original Message ----- =
</span></font><font
size=2 color=black face=Arial><span lang=EN-GB =
style='font-size:10.0pt;
font-family:Arial;color:black;mso-color-alt:windowtext;mso-ansi-language:=
EN-GB'><o:p></o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:3.75pt;background:#E4E4E4;border:none;mso-border-left-alt:sol=
id black 1.5pt;
padding:0cm;mso-padding-alt:0cm 0cm 0cm 4.0pt'><b><font size=2 =
color=black
face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:Arial;
color:black;mso-ansi-language:EN-GB;font-weight:bold'>
<div style='font-color:black'>From:</span></font></b><font size=2 =
color=black
face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:Arial;
color:black;mso-ansi-language:EN-GB'> </span></font><font size=2 =
color=black
face=Arial><span =
style='font-size:10.0pt;font-family:Arial;color:black'><a
href="mailto:eromlignod@kc.rr.com" =
title="eromlignod@kc.rr.com"><span
lang=EN-GB style='mso-ansi-language:EN-GB'>Don A. =
Gilmore</span></a></span></font><font
size=2 color=black face=Arial><span =
style='font-size:10.0pt;font-family:Arial;
color:black;mso-ansi-language:EN-GB'> </span></font></div>
<font size=2 color=black face=Arial><span lang=EN-GB =
style='font-size:10.0pt;
font-family:Arial;color:black;mso-color-alt:windowtext;mso-ansi-language:=
EN-GB'><o:p></o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:3.75pt;border:none;mso-border-left-alt:solid black 1.5pt;
padding:0cm;mso-padding-alt:0cm 0cm 0cm 4.0pt'><b><font size=2 =
color=black
face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:Arial;
color:black;mso-ansi-language:EN-GB;font-weight:bold'>To:</span></font></=
b><font
size=2 color=black face=Arial><span lang=EN-GB =
style='font-size:10.0pt;
font-family:Arial;color:black;mso-ansi-language:EN-GB'> =
</span></font><font
size=2 color=black face=Arial><span =
style='font-size:10.0pt;font-family:Arial;
color:black'><a href="mailto:pianotech@ptg.org" =
title="pianotech@ptg.org"><span
lang=EN-GB =
style='mso-ansi-language:EN-GB'>Pianotech</span></a></span></font><font=
size=2 color=black face=Arial><span =
style='font-size:10.0pt;font-family:Arial;
color:black;mso-ansi-language:EN-GB'> </span></font><font size=2 =
color=black
face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:Arial;
color:black;mso-color-alt:windowtext;mso-ansi-language:EN-GB'><o:p></o:p>=
</span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:3.75pt;border:none;mso-border-left-alt:solid black 1.5pt;
padding:0cm;mso-padding-alt:0cm 0cm 0cm 4.0pt'><b><font size=2 =
color=black
face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:Arial;
color:black;mso-ansi-language:EN-GB;font-weight:bold'>Sent:</span></font>=
</b><font
size=2 color=black face=Arial><span lang=EN-GB =
style='font-size:10.0pt;
font-family:Arial;color:black;mso-ansi-language:EN-GB'> Friday, December =
19,
2003 12:22 AM</span></font><font size=2 color=black =
face=Arial><span
lang=EN-GB =
style='font-size:10.0pt;font-family:Arial;color:black;mso-color-alt:
windowtext;mso-ansi-language:EN-GB'><o:p></o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:3.75pt;border:none;mso-border-left-alt:solid black 1.5pt;
padding:0cm;mso-padding-alt:0cm 0cm 0cm 4.0pt'><b><font size=2 =
color=black
face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:Arial;
color:black;mso-ansi-language:EN-GB;font-weight:bold'>Subject:</span></fo=
nt></b><font
size=2 color=black face=Arial><span lang=EN-GB =
style='font-size:10.0pt;
font-family:Arial;color:black;mso-ansi-language:EN-GB'> Re: Cockeyed =
hammers /
Don Gilmore</span></font><font size=2 color=black face=Arial><span =
lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:black;mso-color-alt:win=
dowtext;
mso-ansi-language:EN-GB'><o:p></o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:3.75pt;border:none;mso-border-left-alt:solid black 1.5pt;
padding:0cm;mso-padding-alt:0cm 0cm 0cm 4.0pt'><font size=3 =
color=black
face="Times New Roman"><span lang=EN-GB =
style='font-size:12.0pt;color:black;
mso-ansi-language:EN-GB'><![if =
!supportEmptyParas]> <![endif]></span></font><font
color=black><span lang=EN-GB =
style='color:black;mso-color-alt:windowtext;
mso-ansi-language:EN-GB'><o:p></o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:3.75pt;border:none;mso-border-left-alt:solid black 1.5pt;
padding:0cm;mso-padding-alt:0cm 0cm 0cm 4.0pt'><font size=2 =
color=black
face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:Arial;
color:black;mso-ansi-language:EN-GB'>Well, I didn't mean to imply =
that the
impulse at the pivot is all absorbed; but it is all lost as far as the =
string
is concerned.</span></font><font size=2 color=black =
face=Arial><span
lang=EN-GB =
style='font-size:10.0pt;font-family:Arial;color:black;mso-color-alt:
windowtext;mso-ansi-language:EN-GB'><o:p></o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:3.75pt;border:none;mso-border-left-alt:solid black 1.5pt;
padding:0cm;mso-padding-alt:0cm 0cm 0cm 4.0pt'><font size=2 =
color=black
face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:Arial;
color:black;mso-ansi-language:EN-GB'> </span></font><font size=2
color=black face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:
Arial;color:black;mso-color-alt:windowtext;mso-ansi-language:EN-GB'><o:p>=
</o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:3.75pt;border:none;mso-border-left-alt:solid black 1.5pt;
padding:0cm;mso-padding-alt:0cm 0cm 0cm 4.0pt'><font size=2 =
color=black
face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:Arial;
color:black;mso-ansi-language:EN-GB'>The center of percussion is one of =
those
counter-intuitive phenomena in dynamics. For the multitude of =
college
students that only take a semester or two of physics, the concept of =
forces on
a free body acting at the center of gravity is a paradigm that is hard =
to
dislodge. For an object in free space or translating in a =
straight
line, which comprises most situations, the center of gravity is =
always
used. But for an object pivoted at some location other than its =
c.g., all
bets are off. The most publicized version of this is a baseball =
bat's
"sweet spot" as you described.</span></font><font size=2 =
color=black
face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:Arial;
color:black;mso-color-alt:windowtext;mso-ansi-language:EN-GB'><o:p></o:p>=
</span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:3.75pt;border:none;mso-border-left-alt:solid black 1.5pt;
padding:0cm;mso-padding-alt:0cm 0cm 0cm 4.0pt'><font size=2 =
color=black
face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:Arial;
color:black;mso-ansi-language:EN-GB'> </span></font><font size=2
color=black face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:
Arial;color:black;mso-color-alt:windowtext;mso-ansi-language:EN-GB'><o:p>=
</o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:3.75pt;border:none;mso-border-left-alt:solid black 1.5pt;
padding:0cm;mso-padding-alt:0cm 0cm 0cm 4.0pt'><font size=2 =
color=black
face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:Arial;
color:black;mso-ansi-language:EN-GB'>Think of a wooden board hung from a =
pivot
point at its top. If you strike the board up near the hinge, the =
pin will
experience a force coming from the direction of the strike. But if =
you
strike the board at the bottom, the pin will experience a force in the =
opposite
direction as the board tries to spin about its center. There is a =
point
in between these two where the pin force is neither positive nor =
negative and
the pin will actually see <em><i>no</i></em> force. This is the =
center of
percussion and is <em><i>not</i></em> located at the centroid of the
board. It's not usually even particularly =
close.</span></font><font
size=2 color=black face=Arial><span lang=EN-GB =
style='font-size:10.0pt;
font-family:Arial;color:black;mso-color-alt:windowtext;mso-ansi-language:=
EN-GB'><o:p></o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:3.75pt;border:none;mso-border-left-alt:solid black 1.5pt;
padding:0cm;mso-padding-alt:0cm 0cm 0cm 4.0pt'><font size=2 =
color=black
face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:Arial;
color:black;mso-ansi-language:EN-GB'> </span></font><font size=2
color=black face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:
Arial;color:black;mso-color-alt:windowtext;mso-ansi-language:EN-GB'><o:p>=
</o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:3.75pt;border:none;mso-border-left-alt:solid black 1.5pt;
padding:0cm;mso-padding-alt:0cm 0cm 0cm 4.0pt'><font size=2 =
color=black
face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:Arial;
color:black;mso-ansi-language:EN-GB'>It would seem to be a good =
idea to
design the hammer so that the string contact point of the head =
passes
through the center of percussion. That way the maximum amount of
energy would be transmitted to the string...like dropping a ball on
it. But I'm not sure if they actually design them that =
way.</span></font><font
size=2 color=black face=Arial><span lang=EN-GB =
style='font-size:10.0pt;
font-family:Arial;color:black;mso-color-alt:windowtext;mso-ansi-language:=
EN-GB'><o:p></o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:3.75pt;border:none;mso-border-left-alt:solid black 1.5pt;
padding:0cm;mso-padding-alt:0cm 0cm 0cm 4.0pt'><font size=2 =
color=black
face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:Arial;
color:black;mso-ansi-language:EN-GB'> </span></font><font size=2
color=black face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:
Arial;color:black;mso-color-alt:windowtext;mso-ansi-language:EN-GB'><o:p>=
</o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:3.75pt;border:none;mso-border-left-alt:solid black 1.5pt;
padding:0cm;mso-padding-alt:0cm 0cm 0cm 4.0pt'><font size=2 =
color=black
face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:Arial;
color:black;mso-ansi-language:EN-GB'>Don A. Gilmore<br>
Mechanical Engineer<br>
Kansas City</span></font><font size=2 color=black face=Arial><span =
lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:black;mso-color-alt:win=
dowtext;
mso-ansi-language:EN-GB'><o:p></o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:3.75pt;border:none;mso-border-left-alt:solid black 1.5pt;
padding:0cm;mso-padding-alt:0cm 0cm 0cm 4.0pt'><font size=2 =
color=black
face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:Arial;
color:black;mso-ansi-language:EN-GB'> </span></font><font size=2
color=black face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:
Arial;color:black;mso-color-alt:windowtext;mso-ansi-language:EN-GB'><o:p>=
</o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:3.75pt;border:none;mso-border-left-alt:solid black 1.5pt;
padding:0cm;mso-padding-alt:0cm 0cm 0cm 4.0pt'><font size=3 =
color=black
face="Times New Roman"><span lang=EN-GB =
style='font-size:12.0pt;color:black;
mso-ansi-language:EN-GB'>----- Original Message ----- =
</span></font><font
color=black><span lang=EN-GB =
style='color:black;mso-color-alt:windowtext;
mso-ansi-language:EN-GB'><o:p></o:p></span></font></p>
</div>
<div style='border:none;border-left:solid black 1.5pt;padding:0cm 0cm =
0cm 4.0pt;
background:#E4E4E4'>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:7.5pt;border:none;mso-border-left-alt:solid black =
1.5pt;padding:
0cm;mso-padding-alt:0cm 0cm 0cm 4.0pt'><b><font size=2 color=black =
face=Arial><span
lang=EN-GB =
style='font-size:10.0pt;font-family:Arial;color:black;mso-ansi-language=
:
EN-GB;font-weight:bold'>
<div style='font-color:black'>From:</span></font></b><font size=2 =
color=black
face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:Arial;
color:black;mso-ansi-language:EN-GB'> </span></font><font size=2 =
color=black
face=Arial><span =
style='font-size:10.0pt;font-family:Arial;color:black'><a
href="mailto:sarah@gendernet.org" title="sarah@gendernet.org"><span =
lang=EN-GB
style='mso-ansi-language:EN-GB'>Sarah =
Fox</span></a></span></font><font size=2
color=black face=Arial><span =
style='font-size:10.0pt;font-family:Arial;
color:black;mso-ansi-language:EN-GB'> </span></font></div>
<font size=2 color=black face=Arial><span lang=EN-GB =
style='font-size:10.0pt;
font-family:Arial;color:black;mso-color-alt:windowtext;mso-ansi-language:=
EN-GB'><o:p></o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:7.5pt;background:white;mso-shading:transparent;border:none;
mso-border-left-alt:solid black 1.5pt;padding:0cm;mso-padding-alt:0cm =
0cm 0cm 4.0pt'><b><font
size=2 color=black face=Arial><span lang=EN-GB =
style='font-size:10.0pt;
font-family:Arial;color:black;mso-ansi-language:EN-GB;font-weight:bold'>T=
o:</span></font></b><font
size=2 color=black face=Arial><span lang=EN-GB =
style='font-size:10.0pt;
font-family:Arial;color:black;mso-ansi-language:EN-GB'> =
</span></font><font
size=2 color=black face=Arial><span =
style='font-size:10.0pt;font-family:Arial;
color:black'><a href="mailto:pianotech@ptg.org" =
title="pianotech@ptg.org"><span
lang=EN-GB =
style='mso-ansi-language:EN-GB'>Pianotech</span></a></span></font><font=
size=2 color=black face=Arial><span =
style='font-size:10.0pt;font-family:Arial;
color:black;mso-ansi-language:EN-GB'> </span></font><font size=2 =
color=black
face=Arial><span lang=EN-GB =
style='font-size:10.0pt;font-family:Arial;
color:black;mso-color-alt:windowtext;mso-ansi-language:EN-GB'><o:p></o:p>=
</span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:7.5pt;background:white;mso-shading:transparent;border:none;
mso-border-left-alt:solid black 1.5pt;padding:0cm;mso-padding-alt:0cm =
0cm 0cm 4.0pt'><b><font
size=2 color=black face=Arial><span lang=EN-GB =
style='font-size:10.0pt;
font-family:Arial;color:black;mso-ansi-language:EN-GB;font-weight:bold'>S=
ent:</span></font></b><font
size=2 color=black face=Arial><span lang=EN-GB =
style='font-size:10.0pt;
font-family:Arial;color:black;mso-ansi-language:EN-GB'> Thursday, =
December 18,
2003 2:38 AM</span></font><font size=2 color=black =
face=Arial><span lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:black;mso-color-alt:win=
dowtext;
mso-ansi-language:EN-GB'><o:p></o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:7.5pt;background:white;mso-shading:transparent;border:none;
mso-border-left-alt:solid black 1.5pt;padding:0cm;mso-padding-alt:0cm =
0cm 0cm 4.0pt'><b><font
size=2 color=black face=Arial><span lang=EN-GB =
style='font-size:10.0pt;
font-family:Arial;color:black;mso-ansi-language:EN-GB;font-weight:bold'>S=
ubject:</span></font></b><font
size=2 color=black face=Arial><span lang=EN-GB =
style='font-size:10.0pt;
font-family:Arial;color:black;mso-ansi-language:EN-GB'> Cockeyed hammers =
/ Don
Gilmore</span></font><font size=2 color=black face=Arial><span =
lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:black;mso-color-alt:win=
dowtext;
mso-ansi-language:EN-GB'><o:p></o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:7.5pt;background:white;mso-shading:transparent;border:none;
mso-border-left-alt:solid black 1.5pt;padding:0cm;mso-padding-alt:0cm =
0cm 0cm 4.0pt'><font
size=3 color=black face="Times New Roman"><span lang=EN-GB =
style='font-size:
12.0pt;color:black;mso-ansi-language:EN-GB'><![if =
!supportEmptyParas]> <![endif]></span></font><font
color=black><span lang=EN-GB =
style='color:black;mso-color-alt:windowtext;
mso-ansi-language:EN-GB'><o:p></o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:7.5pt;background:white;mso-shading:transparent;border:none;
mso-border-left-alt:solid black 1.5pt;padding:0cm;mso-padding-alt:0cm =
0cm 0cm 4.0pt'><font
size=2 color=black face="Courier New"><span lang=EN-GB =
style='font-size:10.0pt;
font-family:"Courier New";color:black;mso-ansi-language:EN-GB'>Probably =
any
baseball player would know that it's not smart to hit the ball with the =
very
tip of the bat. It makes for a nasty shock to the hands (and to =
the
extent that the hands are not rigid in space, it takes away from the =
power
transferred to the ball). Why do they do this with piano =
hammers? More
to the point, is this not considered an unneccessary demand to put on =
the
hammer flanges and bushings? Perhaps it's also a drain on
efficiency? Wouldn't it make sense to have some sort of =
asymmetrical molding
whose center of mass is on the far side of the action center, so as to =
put the
center of mass of the hammer assembly closer to the line of =
strike?</span></font><font
color=black><span lang=EN-GB =
style='color:black;mso-color-alt:windowtext;
mso-ansi-language:EN-GB'><o:p></o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:7.5pt;background:white;mso-shading:transparent;border:none;
mso-border-left-alt:solid black 1.5pt;padding:0cm;mso-padding-alt:0cm =
0cm 0cm 4.0pt'><font
size=3 color=black face="Times New Roman"><span lang=EN-GB =
style='font-size:
12.0pt;color:black;mso-ansi-language:EN-GB'> </span></font><font
color=black><span lang=EN-GB =
style='color:black;mso-color-alt:windowtext;
mso-ansi-language:EN-GB'><o:p></o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:7.5pt;background:white;mso-shading:transparent;border:none;
mso-border-left-alt:solid black 1.5pt;padding:0cm;mso-padding-alt:0cm =
0cm 0cm 4.0pt'><font
size=2 color=black face="Courier New"><span lang=EN-GB =
style='font-size:10.0pt;
font-family:"Courier New";color:black;mso-ansi-language:EN-GB'>Also, =
wouldn't
it at least make sense to angle the head of the hammer inwards slightly, =
so
that the radius to the head's center of mass is perpendicular to =
the
strike axis of the head? It seems to me that this would help to =
control
wobble in the hammer</span></font><font color=black><span lang=EN-GB
style='color:black;mso-color-alt:windowtext;mso-ansi-language:EN-GB'><o=
:p></o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:7.5pt;background:white;mso-shading:transparent;border:none;
mso-border-left-alt:solid black 1.5pt;padding:0cm;mso-padding-alt:0cm =
0cm 0cm 4.0pt'><font
size=3 color=black face="Times New Roman"><span lang=EN-GB =
style='font-size:
12.0pt;color:black;mso-ansi-language:EN-GB'> </span></font><font
color=black><span lang=EN-GB =
style='color:black;mso-color-alt:windowtext;
mso-ansi-language:EN-GB'><o:p></o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:7.5pt;background:white;mso-shading:transparent;border:none;
mso-border-left-alt:solid black 1.5pt;padding:0cm;mso-padding-alt:0cm =
0cm 0cm 4.0pt'><font
size=2 color=black face="Courier New"><span lang=EN-GB =
style='font-size:10.0pt;
font-family:"Courier New";color:black;mso-ansi-language:EN-GB'>I'm not =
sure I
agree about part of the impact being "absorbed" by the =
pivot. Sure,
there would be force against the pivot, but for impact to be absorbed, =
the
pivot would need to be compliant and inelastic. I realize that's =
true to
an extent, as no system is ideal. However, do you think this would =
be a
substantial drain of energy? It seems to me that the hammer felt =
and the
strings are far more compliant and are closer to the center of mass, =
such that
almost all of the energy would be dissipated there (rather than at the
comparatively rigid center). Have you ever measured =
this?</span></font><font
color=black><span lang=EN-GB =
style='color:black;mso-color-alt:windowtext;
mso-ansi-language:EN-GB'><o:p></o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:7.5pt;background:white;mso-shading:transparent;border:none;
mso-border-left-alt:solid black 1.5pt;padding:0cm;mso-padding-alt:0cm =
0cm 0cm 4.0pt'><font
size=3 color=black face="Times New Roman"><span lang=EN-GB =
style='font-size:
12.0pt;color:black;mso-ansi-language:EN-GB'> </span></font><font
color=black><span lang=EN-GB =
style='color:black;mso-color-alt:windowtext;
mso-ansi-language:EN-GB'><o:p></o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:7.5pt;background:white;mso-shading:transparent;border:none;
mso-border-left-alt:solid black 1.5pt;padding:0cm;mso-padding-alt:0cm =
0cm 0cm 4.0pt'><font
size=2 color=black face="Courier New"><span lang=EN-GB =
style='font-size:10.0pt;
font-family:"Courier New";color:black;mso-ansi-language:EN-GB'>Just =
curious on
your take. I can't do much more than scratch my head about this
one. If the hammer were perfectly rigid and the center bullet =
proof and
noncompliant, there'd be nothing to worry about. But considering =
that it
does the hokey pokey and shimmies all about... Well, I don't =
know.</span></font><font
color=black><span lang=EN-GB =
style='color:black;mso-color-alt:windowtext;
mso-ansi-language:EN-GB'><o:p></o:p></span></font></p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:7.5pt;background:white;mso-shading:transparent;border:none;
mso-border-left-alt:solid black 1.5pt;padding:0cm;mso-padding-alt:0cm =
0cm 0cm 4.0pt'><font
size=3 color=black face="Times New Roman"><span lang=EN-GB =
style='font-size:
12.0pt;color:black;mso-ansi-language:EN-GB'> </span></font><font
color=black><span lang=EN-GB =
style='color:black;mso-color-alt:windowtext;
mso-ansi-language:EN-GB'><o:p></o:p></span></font></p>
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style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:7.5pt;background:white;mso-shading:transparent;border:none;
mso-border-left-alt:solid black 1.5pt;padding:0cm;mso-padding-alt:0cm =
0cm 0cm 4.0pt'><font
size=2 color=black face="Courier New"><span =
style='font-size:10.0pt;font-family:
"Courier New";color:black'>Peace,</span></font><font color=black><span
style='color:black;mso-color-alt:windowtext'><o:p></o:p></span></font><=
/p>
<p class=MsoNormal =
style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:7.5pt;background:white;mso-shading:transparent;border:none;
mso-border-left-alt:solid black 1.5pt;padding:0cm;mso-padding-alt:0cm =
0cm 0cm 4.0pt'><font
size=2 color=black face="Courier New"><span =
style='font-size:10.0pt;font-family:
"Courier New";color:black'>Sarah</span></font><font color=black><span
style='color:black;mso-color-alt:windowtext'><o:p></o:p></span></font><=
/p>
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