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<DIV><FONT size=2>It's hard to say whether there is really an =
<EM>incorrect
</EM>key ratio. The key ratio is only incorrect in so far as it
contributes to an overall ratio which is too high or too low. =
To
simplify, it's really how it combines with the knuckle radius that's
important. Whereas a .52 KR might not work with a 15.5 mm knuckle =
radius,
it will work fine with a 17 mm one, generally. Similarly, a .55 =
KR, as you
sometimes find in older Mason Hamlins or Baldwins, will require an 18 mm =
knuckle
to get the overall ratio in the 5.5 - 5.9 area where (I think) it =
belongs.
There are, of course, other considerations in choosing this combination =
of
levers. The smaller the knuckle radius the greater will be the =
friction
because of the increased weight bearing on the knuckle. So if you =
are
opting for a heavier hammer, you are better off going with a longer =
knuckle
radius. Very light hammers, as are found in older Steinways, do =
just fine
with shorter knuckle dimensions without too great an increase in =
friction.
Just a few thoughts.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>David Love </FONT></DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>
<A title=tompiano@gate.net href="mailto:tompiano@gate.net">Tom =
Servinsky</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A =
title=pianotech@ptg.org
href="mailto:pianotech@ptg.org">pianotech@ptg.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> July 13, 2002 5:23 =
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> RE: Lighter or Heavier =
?</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN =
class=650010312-13072002>I
there was a "theme" to this year's convention IMHO, it was diagnosing =
key
ratios. Between Stanwood's all-day class and Richard Davenport's "What =
if",
incorrect key ratios have to be dealt with during our rebuilding
procedures, or our problems will continue.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN =
class=650010312-13072002>The
common plan of attack for a number of years has always been to add =
lead when
the key weight is too extreme (high). Even though we get the DW =
down ...
something always hinted that we were treating the symptoms and not the =
disease.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=650010312-13072002>Incorrect key ratio creates a =
vicious cycle
that affects everything. We have to learn to understand and correct =
these
problems and make them a normal part of the rebuilding
procedure.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN =
class=650010312-13072002>Tom
Servinksy,RPT </SPAN></FONT></DIV>
<DIV><SPAN class=650010312-13072002></SPAN><FONT face=Tahoma><FONT =
size=2><SPAN class=650010312-13072002><FONT face=Arial
color=#0000ff></FONT></SPAN></FONT></FONT> </DIV>
<DIV><FONT face=Tahoma><FONT size=2><SPAN
class=650010312-13072002> </SPAN><STRONG>:</STRONG>
owner-pianotech@ptg.org [mailto:owner-pianotech@ptg.org]<B>On Behalf =
Of
</B>Erwinspiano@AOL.COM<BR><B>Sent:</B> Friday, July 12, 2002 10:26
PM<BR><B>To:</B> pianotech@ptg.org<BR><B>Subject:</B> Re: Lighter or =
Heavier
?<BR><BR></DIV></FONT>
<BLOCKQUOTE></FONT><FONT face=arial,helvetica><FONT lang=0
face="Times New Roman" size=3 FAMILY="SERIF">In a message =
dated 7/12/2002
4:20:20 PM Pacific Daylight Time, Richard.Brekne@grieg.uib.no
writes:<BR><BR></FONT><FONT lang=0 style="BACKGROUND-COLOR: =
#ffffff"
face=Arial color=#000000 size=3 FAMILY="SANSSERIF"><BR>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff =
2px solid; MARGIN-RIGHT: 0px"
TYPE="CITE">Subj:<B>Re: Lighter or Heavier ? =
</B><BR>Date:7/12/2002
4:20:20 PM Pacific Daylight Time<BR>From:<A
=
href="mailto:Richard.Brekne@grieg.uib.no">Richard.Brekne@grieg.uib.no</=
A><BR>Reply-to:<A
href="mailto:pianotech@ptg.org">pianotech@ptg.org</A><BR>To:<A
href="mailto:pianotech@ptg.org">pianotech@ptg.org</A><BR>Sent =
from the
Internet <BR><BR> Hey
Ric</BLOCKQUOTE><BR><BR></FONT><FONT lang=0
style="BACKGROUND-COLOR: #ffffff" face="Times New Roman" =
color=#000000
size=3 FAMILY="SERIF"> I =
followed this
only briefly. Bussssy week. Oh my goodness! Any way There is an =
experience
I've had a few times with some actions where the key ratios and =
action
ratios were really good. Without getting into many measurements just =
let me
say that the effect was that even though static down weights =
approached 60
down on my Symphony Stwy D (1940) and the upweights were a nice =
snappy
28-30. No one has ever complained about the touch as being heavy.
<BR> John O' Connor played it a time or two as well as =
others.
and never a complaint about the touch being heavy. Seems to =
handle
rapid passage work effortlessly. It has some lead closer to the =
balance rail
as it's a accelerated action.
<BR> I've also learned from installing =
new key
sets with corrected key ratios that less lead is used and similar =
results
are attained. I believe some lead is required to give =
the
piansit some semblance of a "the normal feel" related to =
inertia and
that some inertia IMO is desirable in a piano action. Physics says =
were
going to have some like it or not but is better managed with =
efficient
leverages. When some of these systems are right it's like a
supercharged V-8.<BR> My point is that the down weight =
upweight
discussion takes on an entirely different parameters when things are =
set up
right as opposed to the funky key and action geometry we deal with =
day in
and out. Bottom line is that some action.key systems static weights =
may seem
high ( 60 over 30 ) but the dynamic effect when the keys are in =
motion tells
an entirely different and pleasant story.<BR> Does that make =
sense to
any one but me?<BR> >>>>Dale
Erwin>>>>>>></FONT><FONT lang=0
style="BACKGROUND-COLOR: #ffffff" face=Arial color=#000000 =
size=3
FAMILY="SANSSERIF"><BR></FONT><FONT lang=0 =
style="BACKGROUND-COLOR: #ffffff"
face=Arial color=#000000 size=2 FAMILY="SANSSERIF"><BR>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff =
2px solid; MARGIN-RIGHT: 0px"
TYPE="CITE"><BR>Thanks again Ed and Dave... and Stéphane for =
your
interest<BR><BR>Seems like we have two ideas about how inertia =
levels
affect<BR>the touch of the piano. On the one hand we've said
several<BR>times the the higher the inertia the slower the
action<BR>repetition... and this has been equated loosely with
terms<BR>like sluggishness and then from this perspective,
heaviness.<BR>Then on the other hand a bit more lead is said to
perhaps<BR>lead to a lighter "feel" due to the help inertia lends
ones<BR>the key is in motion.<BR><BR>Interesting and to some =
degree
conflicting lines of<BR>thinking. All and all it leads one to =
think that
Stanwood<BR>ideas are fine.... a great refinement in relation to
simple<BR>DW/UW measurements.. but perhaps should be refined =
further<BR>to
somehow put a number on inertia .... inertia =
zones<BR>perhaps.<BR><BR>I
agree tho in the answers you two kindly voluntered that<BR>DW/UW =
has a
direct relationship to "touch" or "feel", yet<BR>that these are =
also
affected by other relationships. <BR><BR>Thanks again... would =
have liked
to heard from others...<BR>but.
:)<BR><BR>Cheers<BR>RicB<BR></BLOCKQUOTE><BR></FONT><FONT lang=0
style="BACKGROUND-COLOR: #ffffff" face="Times New Roman" =
color=#000000
size=2
FAMILY="SERIF"><I><BR></BLOCKQUOTE></BLOCKQUOTE></I></FONT></FONT></BOD=
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