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 > > > > Yahoo! Canada Toolbar : Search from anywhere on the web and > bookmark your favourite sites. Download it now! > -------------- next part -------------- An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/caut.php/attachments/20080514/40ff9dc6/attachment.html
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