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<DIV><FONT size=4> </FONT><FONT size=3> <STRONG>Hi Keith
</STRONG></FONT></DIV>
<DIV><FONT size=3><STRONG> I read your post & any one reading th=
is
will have a better understanding of the dynamic relationship of action parts=
in
an upright. Nice job. Yes even your mentor learned a few
things.</STRONG></FONT></DIV>
<DIV><STRONG><FONT size=3> I have often weigh upright hammers =
in the
big old uprights we restore & I find the original hammer weight is alway=
s
light as are the grand from the time period</FONT></STRONG></DIV>
<DIV><STRONG><FONT size=3> . On the Ludwig upright curre=
ntly
in process & used the AA Wurzen felt with the Maple moldings & I fou=
nd
that even tapering the whole set in my tablesaw jig I was still a fair bit
heavier but close enough. I juiced only the bass lightly. The rest of the se=
t
got nothing except the usual filing that you & I are accustomed to=
.I
find uprights do not need or benefit from a heavy hammer & that ex=
tra
weight really tend to kill the sound especiall in the top 3
octaves.</FONT></STRONG></DIV>
<DIV><FONT size=3><STRONG> Thank you grasshopper</STRONG></FONT></DIV=
>
<DIV><FONT size=3><STRONG> Regards</STRONG></FONT></DIV>
<DIV><FONT size=3><STRONG> Dale</STRONG></FONT></DIV>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT
style="BACKGROUND-COLOR: transparent" face=Arial color=#000000 size=
=2>
<DIV><FONT face=Georgia size=2>Mistake 1; Assuming action geometry wou=
ld solve
an upright weight problem.</FONT></DIV>
<DIV><FONT face=Georgia size=2></FONT> </DIV>
<DIV><FONT face=Georgia size=2>Mistake 2; Assuming leading would solve=
an
upright weight problem.</FONT></DIV>
<DIV><FONT face=Georgia size=2></FONT> </DIV>
<DIV><FONT face=Georgia size=2>Mistake 3; Assuming a little stronger j=
ack
spring wouldn't hurt.</FONT></DIV>
<DIV><FONT face=Georgia size=2>Mistake 4; Assuming... </FONT></DIV>
<DIV><FONT face=Georgia size=2>Mistake 5; Assuming....</FONT></DIV>
<DIV><FONT face=Georgia size=2></FONT> </DIV>
<DIV><FONT face=Georgia size=2>This is theory, I'm assuming I'm
right.</FONT></DIV>
<DIV><FONT face=Georgia size=2></FONT> </DIV>
<DIV><FONT face=Georgia size=2>I thought action geometry could solve a=
touchweight problem on an upright. First clue; I have heard it said (must =
be
an old wives tale), "you can hang a heavy hammer because the weight of the=
hammer doesn't matter in an upright". True. A mistake would be=
to
not lighten the hammer as much as possible. A too heavy of a hammer will c=
rush
the butt leather and pressure the flange bushing and not have a clean rebo=
und.
However, the ability to accelerate a heavy hammer is there. The key here i=
s
knowing that the wippen in an upright is a 2nd class lever on the lif=
t
and a 3rd class lever on return. In a grand, the opposite is true. So an
upright being a more efficient lift mechanism, mass is less important.
<STRONG>The upright action geometry is designed for proper</STRONG>
<STRONG>distance/movement of the wippen</STRONG> and touchweight becomes a=
factor of the spring tensions, a variable, instead of gravity which i=
s
not a variable. You might want to change the geometry if the blow distance=
was
set at 1 and 7/8" with a key dip of 3/8" and a jack that hits the let=
off
rail. Damper lift also needs to be considered. Then the wippen trave=
l
might need to be lessened.</FONT></DIV>
<DIV><FONT face=Georgia size=2></FONT> </DIV>
<DIV><FONT face=Georgia size=2>Back to touchweight. The jack spring is=
a
significant factor in the touchweight. I had a 57 gram DW and a 37gr UW. B=
oth
the tall Pianotech spring and the Schaff spring were too tall. I could hav=
e
determined this by measuring the height of the jack flange. The one on thi=
s
Knabe is short in comparison to the replacement options. So I replaced the=
jack spring with a spinet jack spring from Pianotech and the DW became 47
grams and the UW was 20 grams. I would have thought this was wrong if=
Michael Gamble hadn't posted the target weights from the S&S manual.
<STRONG>Thank you Michael</STRONG>. Obviously the jack spring affects the =
UW
far more than the DW. It functions somewhat as a wippen return spring.&nbs=
p;It
will aid in lifting more weight at the front of the key. The effort of the=
jack spring is a 2nd class lever. The effort of the hammer weight is =
a
3rd class lever and so the hammer spring will have more effect on the=
DW
than the UW. </FONT><FONT face=Georgia size=2><STRONG>The springs cont=
rol
the DW and the UW. </STRONG></FONT></DIV>
<DIV><FONT face=Georgia size=2></FONT> </DIV>
<DIV><FONT face=Georgia size=2>Upward pressure is needed at the capsta=
n. This
would be to maintain capstan/wippen contact during both the up and down
movement of the wippen. This upward pressure is limited by the weight of t=
he
wippen and the low UW and the need of the wippen to drop quickly without t=
he
weight of the hammer. Leading needs to balance the key against the wippen
regardless of hammer weight. The wippen needs to fall on it's own wei=
ght
to allow the jack to reset and have lost motion. <STRONG>Leading
therefore should be to balance the keys as an individual component.</STRON=
G>
Any change in feel will come from the change in hammer weight on
acceleration or messing with spring weights.</FONT></DIV>
<DIV><FONT face=Georgia size=2></FONT> </DIV>
<DIV><FONT face=Georgia size=2>Please comment, discuss, call me stupid=
or
ignorant but substantiate and show the way.</FONT></DIV>
<DIV><FONT face=Georgia size=2></FONT> </DIV>
<DIV><FONT face=Georgia size=2>Keith Roberts</FONT></DIV>
<DIV><FONT face=Georgia size=2>kpiano</FONT></DIV>
<DIV><FONT face=Georgia size=2></FONT> </DIV></FONT></BLOCKQUOTE>=
</DIV>
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