Hello Don, Some comments interposed: Don Mannino wrote: snip..... > > I am surprised that you are not aware of the pinblock fitting in Kawai > pianos (also used by other well known brands). These pianos are made > with rock maple pin bushings, with the bushings actually being plugs > in the plate holes which are drilled at the same time as the > pinblock. The tuning pins therefore pivot on the plate webbing, and > exert a backwards force on the pinblock - towards the pianist, away > from the plate flange. When this design is used, there is no reason > to fit the pinblock, as long as the bushings are hard enough wood. I disagree with this and I am well aware of the fitting used in this method. Having been through the supposed adequacy of this method twenty or so years ago with the factory reps on the West Coast while, at the same time trying to accomdate an unhappy customer who had bought an unstable Kawai piano with the block installed as you describe which had been sold by a Kawai dealer I worked with at the time, as I say, I disagree that this method is equal in efficacy to a properly fitted pinblock. I doubt few technicians working with dealers selling pianos using this method will not have encountered what has been my experience: A higher rate of instability and a significantly larger number of customers - who know nothing of the supposed virtues of any of these methods,- but complain nevetheless because they have a frustrating experience with the sound and a sneaking suspicion their piano should stay in tune better. They flat out say it just doesn't stay in tune well. I have encountered this many times. These problems are, by no means, simply a function of the tuner's skill or frequency of tuning as the factory reps, at least to me, one time claimed. Since then I have, on at least fifteen or twenty pianos, let the tension down, tightened the plate bolts if loose, filled the voids, usually with brass shim stock, but on one occasion with maple wedges, put the system back under tension and had the customer, previously complaining, now note the piano stayed in tune much better and make copious commentary to this point. The KG -2 is, in my experience particularly bad in this respect, although I have corrected the fit on Kawais, Yamahas, Hyundai, and some others, perhaps Young Chang, if memory serves. The proof is in the pudding and, after having seen the difference in performance, simply as a result of insuring an adequate pinblock fit, and, also, hearing comments of technicians who have referred pianos to me for just such problems, I am firmly convinced the one method used by these Asian companies is a mistake and inadequate entirely. When one properly fits a pinblock, as I am sure you know, little can subsequently go wrong if the fitting has been done adequately using a well made block, nor is this difficult to achieve. Yet, by your own commentary, you indicate that something so important and central to the instrument, tuning stability, is allowed to be dependent upon something so ephemeral as the quality of the wood in the bushing. This seems entirely a manifestation of poor judgement to me. Furthermore, it is not dependent merely on the quality of the wood of the bushing but also upon the type, number and placement of pinblock screws, the characteristics of the alloy used in the metal of both screws and tuning pins, the ability of the plate to stay fixed to the rim, and, no doubt, other factors. Also, it renders the entire system much more sensitive, in my opinion, to moisture fluctuations. Admittedly, as you are lucky enough to have had an experience of, some of their pianos will retain an acceptable level of stability, although I would say it takes an exceptional tuner to produce a really great level of stability on such pianos. In my opinion, while one owner may indeed have a piano capable of a reasonable level of stability, other owners may not be so lucky, and another instrument may be seriously deficient in this regard. Further, on most of these pianos, those of Kawai, Yamaha, and of several companies, the block usually contacts the flange to some degree or another, which I think, complicates matters substantially and markedly increases the possiblity of problems. Where this happens, I have actually tracked changes in the fitting over time as the block, apparently, moves, as you say, by pivoting on the bushings or expands and contracts with the moisture content and thus changes the contacting areas. Obviously, an intricate interaction must occur between the moving or expanding of the block, the tension in the strings and the amount of compression in the bushings, wedged as they are, between the side of the hole and the tuning pin. How this aspect of the method could be said to be advisable, or, even, merely acceptable, as regards stability, is a mystery to me. Plainly, such a method, that is relying upon the load being transmitted to the plate by the bushing, and, at the same time, allowing the block to fit the flange through a portion of its length, must demonstrate the drawbacks of either approach and be especially sensitive to moisture cycling, loose plate bolts and pinblock screws, in particular, possibly, thermal expansion, the dreaded compression set so feared here, and possibly, even more readily expose poor or merely adequate hammer technique on the part of the tuner. I think such a method should not be accepted - why rely on a system that can, and, in my opinion, does, go wrong in so many ways when the readily available alternative lacks these vulnerabilities. Most of the pianos that I have repaired, possibly all, have been in this category. Yet, most of the pianos one sees using this method have just such a combination of effects, which is ill-advised, in my opinion. I, too, have never seen a Kawai with the kind of failed pinblock referred to in the earlier post and was surprised to see such commentary, as I believe their blocks themselves are quite adequate. Yet, a negative impression exists, among some technicians as regard this company and I think the instability of their blocks, to whatever degree it does exist, which as I say may be variable, is partly responsible for this impression. The use of this approach suggests to me that the engineers have not properly considered feedback from the field. They certainly have had it from me in times past. Perhaps they come from the same school of thought that designed the Japanese carriers at Midway. > Many technicians in the US have a very hard time picturing this, > because we were all brought up in the Steinway style of construction, > where the pin does not touch the plate (or should not, I guess), so > the plate is being pulled towards the flange and down. In Kawai > pianos (as well as Yamaha), the pinblock is being pushed back. > > Those who tune a lot of Kawai and Yamaha pianos will tell you that > they are as stable as any - as long as the bushings were made with > good wood. I have tuned a very lot of them and would disagree with this. > I have heard about 1 piano made in the 70s where the grade of the wood > in the bushings apparently wasn't hard enough, and the pinblock > moved. But again - I have only heard of this once, and although there > are undoubtedly others, condemning the brand because of the method of > construction reflects a lack of understanding. > > I do think that your not realizing why the pinblocks have not been fit > has made you feel like the company just didn't know any better - which > is a natural conclusion giving the usual technician training. I am > guilty of making the same mistake in the past, and when I first talked > to one of the (very well educated and experienced) Kawai engineers in > Japan about it, the concept was explained fully. I was duly corrected > and told him so - but I told him they should still fit the pinblocks > just to keep the technicians happy :-) Perhaps they should try it to keep the customers happy. (Sorry this was a low blow but I couldn't resist it.). > A few years back Kawai America had a strung plate out of a Kawai grand > piano with pinblock attached (the piano had been dropped from the back > of a moving truck, so we were taking it apart). We loosened the plate > screws, and sure enough the pinblock swung back, away from the flange > just as the engineer said it would. I don't know why it would take an engineer to expect this would be likely to happen. But, one may need an engineer to consider all the other effects of this motion, the forces that produce it and moment associated with it. The proper design, should one be committed to such a system, would be to cast a flange in the plate at the front of the block and plate, thereby trapping the block and stabilizing its motion. Obviously, the factory believes it has a system that works and that this motion is constrained but, as you can see, I must, from experience, disagree. This motion, not competely constrained at times, as I believe it is, although the factory will, no doubt, claim it isn't and that this has been thoroughly analyzed, which it hasn't, contributes to string breakage along with tuning instability, particularly around the fourth octave and upwards as it has, I believe, the effect of forcing upwards the webbing area of the plate, this being also another source of the instability sometimes evident. I believe that the combination of this backwards force and the moment it exerts against the plate, when combined with loose plate bolts, which, of course, should be prevented by proper maintainence but so often are not, account, to some degree, for the frequently found string breakage on such instruments. Usually, the pianos I have repaired with these problems have exhibited string breakage which, in general, ceases upon the repair. The hammers are normally, voiced some too and this may, of course, reduce the subsequent tendancy to breakage, although, this corrective normally has already been tried before the repairs described above have been made and found inadequate. . > > >> > > snip > I don't think that the objections you've received here on the list are > because you are sharing your experiences about problems with > particular pianos, but that you are condemning a brand in general > because of those experiences. You need to realize that all of us tune > these pianos regularly, and saying that Kawai pinblocks will generally > go bad in 10 years is telling hundreds of technicians something that > they know from experiences is not true - our collective experience > does not support your statement, so some have been kind enough (from > Kawai's perspective) to say so. I agree one hundred percent that these blocks do not go bad as described, but there may well be, as I said above, a level of frustration encountered by tuners with these instruments, particularly in certain environments. > > Thanks for giving this issue a little re-consideration, Ron. I hope > that you get the chance to rebuild some more Kawai grands that don't > give you such a negative impression. > > By the way, for those who are wondering, if you do replace the > pinblock in a Kawai, then I recommend that you go ahead and fit the > block to the flange, because duplicating the hard bushing / drilling > procedure used in the factory is not easy. The replacement bushings > are generally pretty soft, and most rebuilders' shop procedures make > pinblock-to-flange fitting a standard operation anyway. > > A last comment to all posters of this list, if I may. One of the > problems with any of us posting strong negative comments on this list, > whether about people or about piano brands, is that these comments are > very commonly reprinted and mis-used. It is very easy for a competing > dealer to pull a message like Ron's from the archives, print it out, > and make photo copies to show all of their customers as to why they > should never buy a Kawai piano. Once a critical comment is written, > whether it is accurate of not, whether opinion or fact, it becomes a > permanently archived nasty tool which can be used against the target > of the criticism. I am sure that negative posts like Ron's are very > rarely done with intentional malice in mind - but they are still used > in very malicious ways, being posted as "a fact from the PTG piano > technician's list." I have no doubt that Ron's post will be returned > to us at Kawai many times by Kawai dealers who get a copy from a > customer, who was given it by a competitor talking down Kawai. It > happens every time a post like that is written. This is why > manufacturers cringe at these kinds of public posts - no matter how > they were intended, they are almost always misused later, and it > really is quite painful. Personally, I believe Kawai, in the Shingeru particularly, and the RX line to a lesser degree, builds a very high quality instrument and has a commendable forward looking attitude, - the ABS parts, which I think are progess for the industry, for example, demonstrate this. To my ear, the Shigeru is the greatest piano ever built in Asia and, truly, an artistic instrument of the first order. Nevertheless, as I see it, where they use the method described above to fit their blocks, a better approach could easily be had, and would, of course, be much more desirable from my perspective even though I have made some good money repairing such problems. Regards, Robin Hufford RPT > > Don Mannino RPT > Kawai America Thought Police :-) > > > > _______________________________________________ > pianotech list info: https://www.moypiano.com/resources/#archives >
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