Thanks, Susan. I was looking for this very file. Finally found it but too late. I'd saved it as a Word file, not in my piano tech stuff. <grin> Avery Todd, RPT Houston > > From: Susan Kline [skline at peak.org] > Sent: Sunday, February 06, 2005 1:50 PM > To: College and University Technicians > Subject: [CAUT] Forefinishing post (was: Key frame placement) > > At 04:06 PM 2/4/2005 -0800, you wrote: > >(Maybe Susan has a copy?) > > Susan JUST HAPPENS to have a copy -- not having a son to "tidy up" my > files, I have been able to go right to it. Of course it helps that this > post dates from 1997, back when I still took the time to sort and organize. > Back then I thought that if my In Box had 300 posts I was way behind. I had > yet to discover that Eudora can handle 5000+ posts in a box and (usually) > not tangle or lose any. Sometimes I wish she WOULD lose some ... > > Best, > Susan > > > ************************************************************************** > In November, 1997, Horace wrote (to Avery): > ************************************************************************** > > NY and Hamburg pianos require very different approaches, depending on the > period of manufacture. > > Some background: > > Prior to W.W.II, both factories manufactured instruments that, while > different in certain ways, were virtually identical in others. So much so > that from the earliest period of the re-establishment of manufacturing in > Hamburg, NY was shipping everything from action parts to completed pianos to > London and Berlin, as well as Hamburg. Yes, parts came this way as well, and > not all models were consistently produced in both plants. > > The destruction of the Hamburg facilities through the firebombing of > Dresden and Hamburg during W.W.II created a real problem. With the end of > the war, NY had its own problems, and insufficient reserves to rebuild in > Germany. Enter Louis Renner, et al. Renner offered to rebuild the facilities > in Hamburg. There was, of course, a catch. The catch was that Steinway would > have to use actions, back actions, hammers, and other parts from Renner. > This began the real divergence between the two branches of the company. The > Renner parts, while generally conforming to NY specifications, actually were > (are) quite different. The reasons do not matter, the matter just is what it > is. The results are the differences of touch and tone which we have come to > expect from the two factories. > > What then, are these differences? > > Let's start with NY. > > The following general procedure was in use up through, roughly, the > 1987-1988 production period. > > First, the location of the keyframe and cheek blocks was set relative to > the arms of the case of the piano. In the earlier days, the keyframe and > keybed were then drilled for tuning pins used as locators. Then the back of > the keybed was planed dead flat. The keyframe was roughly fit to this, (the > forefinisher could only rough-set this because it was usually done without > the keys or the stack) and then the dags were installed. The dags were > located by gluing a piece of 1/8th inch veneer to the back of the keyframe > (or the front of the dag, if the foreman was not looking), and then > inserting the keyframe into the action bay and clamping it in place. The > dags were then glued in place at intervals determined by the location of the > veneer pieces. After the glue had set, the fit of the keyframe was checked > again. (There is a lot of misunderstanding about the purpose of the dags. > They are NOT there just for transportation. They serve the crucial function > {in the NY pianos} of providing stability for the back rail of the action. > Too tight, and the action will not shift reliably. Too loose, and the action > flops around and the touch is not stable.) > > When this is done, the keybed is planed concavely front to back along the > axis of the grain (or perpendicular to the keys, if you prefer). It is > planed such that the depth of the convexity is app. 1/16 inch; and its > deepest point is under the center rail of the keyframe. Then 1/8th to 1/4th > inch of the leading side of the top of the keybed is planed convex by 1/32nd > to 1/16th inch, with the high point at the center of the keybed. The leading > 1/8th to 1/4th inch of the leading edge of the underside of the front rail > is then planed to be a mirror image of the keybed; that is, convex in the > opposite direction by 1/32nd to 1/16th inch. The keyframe is constructed so > that only the end stretchers between the front and back rail are flat. These > are then planed so that they do not touch the keybed, save at the narrow > areas described above. The procedure for locating the cheek blocks has > varied over the years. The most prevalent iteration being to use the > location as set from the arms, and then locate the brass guides relative to > the pins in the keyframe. > > Once that has been done, the keyframe can be inserted and clamped in place > with the cheek blocks, and the forefinisher can work to perfect the mating > of the keyframe and keybed with (hopefully) fine sandpaper. This whole thing > is a part of the overall forefinishing process, which, in Steinway's case, > is a patent process. (Basically, that means that not only can it not be > copied, but they cannot vary from it and still legally use the descriptive > language from the patent documents.) The purpose of this section of the > forefinishing process is to provide the most solid connection of the action > to the balance of the piano possible, so that the pianist may get the > feedback of the vibrations of the piano through the keys. (This speaks > directly to the recent threads on the forum, re: "singing rims" etc.) The > original patent documents describe this feedback quite dramatically and make > interesting reading anyway... > > This process was used from very early on, right up through the use of the > Pratt-Read keys and keyframes, until 1985, when the switch was made to > Renner action parts and Renner and Kluge keys and keyframes. Servicing > keyframes from this period is usually a process of figuring out what was > done during the original manufacture and why it was done. Most often, in my > experience, this has involved some degree of seeing through the mist created > by some well-meaning, but ill-advised colleague. Basically, even if some set > of arbitrary numbers seem to be out of whack, if the original work seems to > have been done a certain way, just follow that. There is usually some (good) > reason that something was done, and most of the time, you just have to redo > your own work when you find out why. > > These pre-1985 keyframes were made of heavy Oak, Walnut and Maple. They > were well seasoned and held regulation well. The Renner/Kluge keyframes are > made of European species, are much lighter and are designed for a different > kind of piano altogether. > > Beginning in 1987-1988, NY began planing the keybeds mostly flat, with > areas of concavity around the maple plugs for the glides. While some > improvements have been made over the earlier keyframes, they are wildly > susceptible to weather changes, as I am sure you have discovered. Further, > their lightness of mass influences not only their ability to hold > regulation, but also their ability to transmit energy. Their planing in the > front rail area is usually limited to the last 4-6" of distance from the > ends of the keyframe, and seems to be further limited to the keybed itself - > there is little, if any, attempt to mirror the work. The result, of course, > is a keyframe which is never quite stable; which brings me to: > > Hamburg keyframes. > > In the period immediately following W.W.II, the Hamburg pianos were, at > first, just put together from whatever could be salvaged from London and > Berlin, as well as Hamburg. There was also, for a time, some bigger pieces > coming from NY. But it was a different world. The influence of Renner can > hardly be overstated. Renner was, and is, the world's largest producer of > piano parts. They make parts to manufacturer's specifications, to be sure; > but, the manufacturers make sure their specifications fit what Renner is set > up to do. No company was/is more in this predicament than Steinway. Has it > been all bad? Definitely not, but it has significantly influenced the course > of the company. So, what about Hamburg? > > What about it, indeed? > > Because things were in turmoil for a while, I will take an arbitrary date > of 1960 for talking about Hamburg keyframes. Yes, it was mostly stable > during the preceding 15 years, but there was variation. Anyway, the post > W.W.II Hamburg piano became a truly European instrument. Nowhere is this > more true than in the concept of the action, and its relation to the rest of > the piano. > > In Hamburg, the keybeds are generally dead flat. None of the planing > described for the NY pianos above. The action frames are what you see on the > post-1985 NY instruments, lightly built and highly susceptible to weather > changes. > > The installation is markedly different as well. All of the fitting is done > to predetermined dimensions. Keyframe, cheek block, dag and action placement > are done independently. At one point (I think it is no longer the case), the > entire action was introduced as a finished unit quite late in the > manufacturing process. The keyframe itself, while arched, is so light that > it depends on the glides for structural support. These actions depend for > their bedding on making things work. The keybed, being flat, does not lend > itself to being replaned. The keyframe, in many of the ones I have seen, is > only planed toward the ends, so that it is a relatively sharp angle. > Smoothing this angle is sometimes all that is needed. > > END > > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech_ptg.org/attachments/20090317/a1cfc253/attachment-0001.html>
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