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<DIV><FONT face=Arial size=2>David-</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Once the hammers are hung, the "pitch" of the
shank/hammer will be altered, so I don't see how the "shank tone" as such
is significant.</FONT></DIV>
<DIV><FONT face=Arial size=2>However, when all other factors are the same, it
may be an indicator of the stiffness of the wood, which may influence the
response of the action. </FONT></DIV>
<DIV><FONT face=Arial size=2>For example, my sense in a short trial of Bruce
Clark's action with carbon fiber shanks was that it was fast and even in
response and delivered easy power for the effort. But that was a short
trial by a low-skilled performer, and there are many other creative adaptations
in his design that make it work so well.</FONT></DIV>
<DIV><FONT face=Arial size=2>Nevertheless, those carbon fiber tubes should be
able to deliver a very perfect and even "plinck" line. not to mention even
weight and stiffness.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Ed Sutton</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=stanwood@tiac.net href="mailto:stanwood@tiac.net">David C.
Stanwood</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=caut@ptg.org
href="mailto:caut@ptg.org">College and University Technicians</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Wednesday, May 14, 2008 6:03
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [CAUT] strikeweight</DIV>
<DIV><BR></DIV>
<DIV>Dear Albert,</DIV>
<DIV><BR></DIV>
<DIV>Great work and very interesting and important ideas you are working
with! My comment: Most of the dead weight is concentrated in the flange
and flange/knuckle end of the shank and I would imagine that for that reason
the dead weight value might relate so much to it's effect on tone...
</DIV>
<DIV><BR></DIV>
<DIV>I would be very interested to see additional data using Shank Strike
Weight (SS) instead of the dead weight of the Flange/Shank
assembly. This value measures the weight of the shank tipped on a
roller bearing with the flange oriented vertically so that it's weight is not
measured. The end of the shank rests on the scale. Values are
usually aroun 1.4g for narrow shanks and 1.8g for regular shanks. We
routinely sort shanks, within each type, by weight, then hang the hammers,
then measure Strikeweights, then add or subtract hammer weight to smooth the
strikeweights to a curve of our choosing.</DIV>
<DIV><BR></DIV>
<DIV>The "thinking" is as follows: Shank Strike Weights can very within
a shank type within a set by as much as 0.6g. These variations
don't show up in the StrikeWeight measure but when we measure the Strikeweight
and make changes in hammer weight to smooth the curve we may be changing
hammer weight to compensate for a variation in SS. .6g of SS will
not have the same inertial moment as .6g of hammer weight because the center
of weight is different. (a physicist could explaing this more
eloquantly than me). So by sorting the SS by weight we theoretically
make the inertial moments of the shank/hammer more even as related to smooth
Strike Weights.</DIV>
<DIV><BR></DIV>
<DIV>Here is a drawing of the setup:</DIV>
<DIV><BR></DIV>
<DIV>http://www.stanwoodpiano.com/ss.jpg</DIV>
<DIV><BR></DIV>
<DIV>Hope this helps.</DIV>
<DIV><BR></DIV>
<DIV>David Stanwood </DIV>
<DIV><BR></DIV>
<DIV><BR></DIV>
<BLOCKQUOTE cite="" type="cite">Hello List</BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite"><BR><I><B>Chris Solliday
<csolliday@rcn.com></B></I> wrote ('way back on Feb 20):<BR>
<BLOCKQUOTE><FONT face=Arial size=-1>Alot of good ideas and ways for
producing some very refined work are being floated regarding shank
radius weight and hammerweight which combine to produce strikeweight
and the action's main contribution to overall tone.
...</FONT></BLOCKQUOTE>
<BLOCKQUOTE>...<FONT face=Arial size=-1>I pre-sort the shanks heavy to
light bass to treble before I channel them and then again after
channeling them. I too find that this reduces the quantity of the
variation if not the relative variation. I do not make a spreadsheet
until that point after the second sorting. ...</FONT></BLOCKQUOTE>
<BLOCKQUOTE><FONT face=Arial size=-1>...I may be going over the shanks
twice but I have much less work in the end.</FONT></BLOCKQUOTE>
<BLOCKQUOTE><FONT face=Arial size=-1>I am intrigued at the possibility of
working shank tone into the equation and will be first looking for a
correlation between pitch and weight.</FONT></BLOCKQUOTE>
<BLOCKQUOTE><FONT face=Arial size=-1>Thanks,</FONT></BLOCKQUOTE>
<BLOCKQUOTE><FONT face=Arial size=-1>Chris
Solliday</FONT><BR></BLOCKQUOTE></BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite"><BR></BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite">This is my first posting to this list, so I
hope at least some of you find what I have to say interesting and/or
useful. Back around mid-February a series of threads
ran on this list entitled "Shank to Hammer weight spreadsheet",
"strikeweight", and "Shank Pitch". The comments at the very end
of Chris Solliday's post (see above) particularly caught my attention,
so I thought I'd do a little "tinking" and weighing to generate some data
which Chris (or anyone else) might find useful.</BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite"> </BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite">My data-gathering proceeded as
follows:</BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite"> </BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite">Taking a box of new Renner shanks with
flanges for Steinway, I first separated the "regular" from the "thinned"
shanks; the set contained 59 and 31 shanks respectively. Then I
listened to the pitch of the shanks and arranged them in order from lowest
to highest. Interestingly, both groups of shanks fell into the
same overall pitch range, i.e. the major third A#5 to D6. The thinned
shanks covered a slightly narrower range, but that is probably due to the
fact that there were fewer of them.</BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite"> </BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite">Next, I weighed each shank/flange assembly
and recorded its weight, to the nearest tenth of a gram. This was
just the dead weight of each assembly on the scale.</BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite"> </BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite">Next, using a Correx gauge, I measured
centre pin friction, also to the nearest tenth of a gram. This
involved some estimating and averaging, but I used a consistent technique,
so I think the numbers are pretty good.</BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite"> </BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite">I entered these data into an Excel
file, and generated charts from them in order to visually
illustrate whatever correlations might exist. The file is
attached, including charts - have a look. The data series with
the connected blue dots represent the regular shanks; the unconnected
pink dots represent the thinned shanks. The lowest- and
highest-pitched thinned shanks are numbered to correspond with the
regular shanks which had the most closely matching pitches; the rest of
the thinned shanks are distributed as evenly as possible between
those two extremes. Distributing them this way enabled me to plot them
all on the same graphs in a somewhat meaningful way.</BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite"> </BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite">Finally, to further explore
the relationships of shank thickness and shank length to shank pitch,
I altered three regular shanks as follows. The first one, which
had an initial weight of 7.0 g (including flange), I thinned
substantially, removing 0.5 g of material. The pitch of this shank
dropped by about a minor 2nd. The second one, which had an initial
weight of 6.9 g (including flange), I shortened by approximately 24-25 mm,
equivalent to 0.4 g of material; the pitch of this shank rose by about a
perfect 4th. The third one, which had an initial weight of 8.5 g (it
had a larger flange attached), I first thinned by 0.5 g, which lowered the
pitch by a little less than a major 2nd. Then I cut off shorter
segments of approximately 7 mm each (each weighing a little under 0.2
g); each of these cuts raised the pitch about a major 2nd; the cumulative
effect of these three cuts was a pitch rise of about a tritone.
Altogether, this last shank ended up thinner, shorter, and about a major
third higher in pitch than where it was at the beginning.</BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite"> </BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite">Some observations/conclusions:</BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite"> </BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite">1. As I mentioned above, both the
regular and thinned shanks fell into the same overall pitch range,
i.e. the major third A#5 to D6. Hence, if one is going to sort shanks
strictly on the basis of pitch, the regular and thinned shanks will end up
being interspersed.</BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite"> </BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite">2. There is a significant amount of overlap
in the weight ranges of the regular and thinned shanks. So if one is
going to sort shanks strictly on the basis of dead weight, again the regular
and thinned shanks will end up being interspersed.</BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite"> </BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite">3. The trendlines in the "Pitch vs. Weight"
chart seem to indicate that, as a general rule, heavier shanks have a higher
pitch. For two reasons, I suspect that the variations in pitch are
primarily a result of differences in wood density from shank to shank.
First, because the substantial thinning I did on two of the shanks I
altered resulted in pitch changes of less than a major 2nd, I doubt
that the slight dimensional variations which may exist after
Renner's precise manufacturing process are likely to result in pitch
differences amounting to a major 3rd. Second, the fact that the
regular and thinned shanks produce pitches that fall within the same range
suggests that something other than dimensional variations are responsible
for the pitch variations. Another obviously potential source of
variation in the weighing process is differences in the weights of the
flanges. But I suspect that if one took the trouble to weigh
the flanges separately, although there would be some
variation, the data would generate a flat trendline.
Anyone wishing to test this hypothesis is welcome to do so; right now I
don't have time.</BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite"> </BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite">4. The random distribution of tighter and
looser flanges throughout the entire range of pitches, and the flat
trendlines in the "Pitch vs. Friction" chart seem to indicate that the pitch
of the shanks is not affected by the pinning (although I do believe the
pinning does affect the tone in the piano). To test this conclusion a
little further, I took a relatively tight assembly, treated it with CLP to
reduce the centre pin friction, and listened to the pitch again; there was
no change in pitch.</BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite"> </BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite">5. Removing material from the end of a shank
has a significantly greater effect on the shank's pitch than does
removing an equivalent amount from the sides. Whether this is
something that needs to be taken into account when sorting shanks may be
worth considering, because when the shank ends are trimmed after the
hammers are installed, they aren't all necessarily shortened by the
same amount.</BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite"> </BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite">The really tough question now
is, what am I going to do with these things?</BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite"> </BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite">Albert (Bert) Picknell</BLOCKQUOTE>
<BLOCKQUOTE cite="" type="cite">Head Piano Technician</BLOCKQUOTE>
<DIV>The Banff Centre<BR></DIV></BLOCKQUOTE></BODY></HTML>