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<title>shank strike weights</title>
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<div class=Section1>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'>Jon:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'>I understand the different heights of the knuckles and the =
effect on
the leverage. Do you also find much disparity in the knuckle =
placement –
i.e. are all 17mm knuckles exactly that far from the center pin or do =
you get a
range? That could also make quite a =
difference.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'>dp<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<div>
<p class=MsoNormal><font size=2 face="Times New Roman"><span =
style='font-size:
10.0pt'>David M. Porritt</span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span =
style='font-size:
10.0pt'><a =
href="mailto:dporritt@smu.edu">dporritt@smu.edu</a></span></font><o:p><=
/o:p></p>
</div>
<div>
<div class=MsoNormal align=center style='text-align:center'><font =
size=3
face="Times New Roman"><span style='font-size:12.0pt'>
<hr size=2 width="100%" align=center tabindex=-1>
</span></font></div>
<p class=MsoNormal><b><font size=2 face=Tahoma><span =
style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font =
size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] <b><span
style='font-weight:bold'>On Behalf Of </span></b>Jon Page<br>
<b><span style='font-weight:bold'>Sent:</span></b> Tuesday, November =
15, 2005
6:59 AM<br>
<b><span style='font-weight:bold'>To:</span></b> pianotech@ptg.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> shank strike =
weights</span></font><o:p></o:p></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'>></span></font><font size=1 color=black =
face=Arial><span
style='font-size:7.5pt;font-family:Arial;color:black'> What is the =
benefit or
what <is> the noticeable difference of =
measuring</span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=1 color=black face=Arial><span =
style='font-size:
7.5pt;font-family:Arial;color:black'>>the knuckle, besides making the =
let
off buttons nice and even and look good?</span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=1 color=black face=Arial><span =
style='font-size:
7.5pt;font-family:Arial;color:black'>I first started measuring knuckle =
and
shank thickness because of what I would</span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=1 color=black face=Arial><span =
style='font-size:
7.5pt;font-family:Arial;color:black'>call a poorly installed set of =
knuckles
and was surprised to find such a wide disparity. Measuring the thickness =
of
many shanks proved to have negligible differences so the differences =
were in the
exactness of pressing the knuckle in. I measure from the =
top</span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=1 color=black face=Arial><span =
style='font-size:
7.5pt;font-family:Arial;color:black'>of the shank to the bottom of the =
knuckle.</span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=1 color=black face=Arial><span =
style='font-size:
7.5pt;font-family:Arial;color:black'>Last year I posted about a knuckle =
caul
press for this concern.</span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=1 color=black face=Arial><span =
style='font-size:
7.5pt;font-family:Arial;color:black'>Subsequent sets measured to have
differences between .5 and 1 mm (.020 - =
.040")</span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=1 color=black face=Arial><span =
style='font-size:
7.5pt;font-family:Arial;color:black'>within the set. I maintain a window =
of .25
mm (.010"), that's +/- .005" (.125 mm) =
from</span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=1 color=black face=Arial><span =
style='font-size:
7.5pt;font-family:Arial;color:black'>the average overall shank/knuckle =
height.
I place the bulk (average) of the shanks</span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=1 color=black face=Arial><span =
style='font-size:
7.5pt;font-family:Arial;color:black'>in the center and the +/-'s at the
extremes. A more level let off button line was just an interesting =
result.</span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=1 color=black face=Arial><span =
style='font-size:
7.5pt;font-family:Arial;color:black'>Action geometry is affected by the =
size of
the knuckle so anything one can do to</span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=1 color=black face=Arial><span =
style='font-size:
7.5pt;font-family:Arial;color:black'>bring uniformity benefits the
action. Priority for shank selection is matching shank =
SW</span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=1 color=black face=Arial><span =
style='font-size:
7.5pt;font-family:Arial;color:black'>to hammer weight with knuckle =
height
second.</span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'>Ultimately the best scenario, inertially speaking, would be to =
graduate
the weight of the hammer heads themselves and group same-weight/knuckle =
height
shanks. But most hammer sets are<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'>so erratic in individual weights that it takes invasive =
procedures to
have them comply.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'>Matching shank SW to hammer weight has proven to require minimal
intervention for<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'>a smooth SW curve.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'>First, I bore and taper the =
hammers.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'>Weight them and plot them on a =
graph.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'>Select shanks accordingly and install them on the rail. (# on =
underside
next to knuckle)<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'>Hang hammers.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'>Remove h/s/f from the rail.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'>Cut the protruding shank off with a band saw and rough cut an =
arc.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'>Set up fence to trim tails on disk sander to even =
length.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'>Arc tails.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'>Weigh SW and plot on chart<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'>Adjust SW<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'>Install h/s/f on rail.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'>I sounds like a lot of work but it goes fast. I like to arc the =
tails
after hanging the hammers<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'>to produce a nice finished edge. I also ease the edges (sides =
and
bottom) of the tail molding<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'>to remove the sharp corners with a =
file.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
<pre><font size=2 face="Courier New"><span =
style='font-size:10.0pt'><x-sigsep>-- <o:p></o:p></span></font></pre>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span =
style='font-size:
12.0pt'><br>
</x-sigsep>Regards,<br>
<br>
Jon Page<o:p></o:p></span></font></p>
</div>
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