Albert,
It would be nice to see a study that correlates strike weight to
pitch. I sorted the last set of shanks I installed first by strike
weight and then checked to see if they were in pitch order. They
weren't. I tried clipping off some excess shank to find a pitch
change, I really couldn't. This particular set only had a variance
of .2 of a gram throughout the entire set. I reordered them by pitch
and installed them in that order. I will continue to sort by pitch
because it makes my voicing much easier.
I respectfully disagree that shank pitch is insignificant. I use the
word "respectfully" purposely. I know the "strikeweight" people have
their reasons for insisting on using their methods to sort, but I
know of others more learned than me who feel that type of sorting is
inconsequential. I am sitting in the middle about the sorting by
weight discussion.
I find there is a very, very wide variance in shank pitch and it
amounts to more than just a few shanks that go "plock". It ends up
being a wide variance with a very even progression of pitch.
I'm not trying to argue here just present experiences that I have and
share them. I have not responded to much of the discussion since I
first brought up the shank pitch. I have not been swayed by the
information presented to change my ways. It isn't worth arguing
about and I want to make sure no one thinks I am trying say my method
is the correct method. I am just saying it is comfortable for me.
Tim Coates
On May 14, 2008, at 7:43 PM, Albert Picknell wrote:
> Thank you, Ed
>
> Your first sentence states directly what I was hinting at in my
> last point, namely that since it would be very difficult to predict
> what resonating qualities a shank/hammer assembly will have once
> the shank ends are trimmed off, it may be rather pointless to try
> to use shank pitch as a primary sorting criterion. And your second
> sentence reminds me of what Ted Sambell taught us many years ago (I
> was one of his students back in the '80's): always listen to the
> tone of the shanks before installing them. The ones that go
> "plink" can go in the piano; the ones that go "plock" can go
> somewhere else. There is no sorting by pitch, just a test that
> weeds out the shanks that are more likely either to break due to
> irregularities in the grain, or to adversely affect the tone by
> flexing too much, damping tone, etc.
>
> Thank you, David, for your comments too. It sounds like there is
> more to be gained by sorting shanks according to what effect they
> will have on the touch rather than what pitch they produce before
> being coupled with hammers and mounted on rails. As long as they
> are good and stiff (they go "plink" rather than "plock") they
> should do the job.
>
> Am I reading you correctly?
>
> Albert
>
>
> Ed Sutton <ed440 at mindspring.com> wrote:
> David-
>
> 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.
> 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.
> 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.
> Nevertheless, those carbon fiber tubes should be able to deliver a
> very perfect and even "plinck" line. not to mention even weight and
> stiffness.
>
> Ed Sutton
> ----- Original Message -----
> From: David C. Stanwood
> To: College and University Technicians
> Sent: Wednesday, May 14, 2008 6:03 PM
> Subject: Re: [CAUT] strikeweight
>
> Dear Albert,
>
> 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...
>
> 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.
>
> 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.
>
> Here is a drawing of the setup:
>
> http://www.stanwoodpiano.com/ss.jpg
>
> Hope this helps.
>
> David Stanwood
>
>
>> Hello List
>>
>> Chris Solliday <csolliday at rcn.com> wrote ('way back on Feb 20):
>> 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. ...
>> ...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. ...
>> ...I may be going over the shanks twice but I have much less work
>> in the end.
>> 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.
>> Thanks,
>> Chris Solliday
>>
>> 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.
>>
>> My data-gathering proceeded as follows:
>>
>> 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.
>>
>> 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.
>>
>> 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.
>>
>> 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.
>>
>> 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.
>>
>> Some observations/conclusions:
>>
>> 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.
>>
>> 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.
>>
>> 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.
>>
>> 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.
>>
>> 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.
>>
>> The really tough question now is, what am I going to do with these
>> things?
>>
>> Albert (Bert) Picknell
>> Head Piano Technician
> The Banff Centre
>
>
>
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