[pianotech] making the Gen-u-whine Steinway

[Encore Pianos]

Thanks for your reply, Ed.  My wording was perhaps less exact than I should have been, so I can understand if you took a different meaning than the one I intended when I talked about the way they fit the pinblock to the plate in the case.  

 

What the factory does is this:  The rough cut pinblock is glued to the stretcher (cornice in Steinway terms) before the stretcher is then glued to the 2 sides of the rim.  The keybed is glued in place also.  Then the plate is suspended over the rim and lowered over the pinblock.  A mini Johnny bar on the keybed lifts and lowers the plate flange, rubbing it against the front of the pinblock.  Exit the plate, and the fitter grinds away the high spots of graphite that have marked the pinblock.  Repeat process until a close plate fit is achieved.  Similarly, the top of the pinblock is ground down to mate to the bottom of the plate, using a router set in a “pantograph” (I think that is the term).  This is the way they achieve the top and face fitting of the pinblock to the case.  

 

We have been seeing the inconsistencies that this brings to the manufacturing process.  In a sense, the piano is built around the plate, so the action placement has to accommodate the vagaries of plate location.  

 

As rebuilders, there are a couple of things that we know.  Anyone who has top fit a pinblock knows how warped plates can be – concave, convex, s-curved, you name it.  Sometimes that warpage can be significant.  Similarly, the plate flange and the rough cut pinblock can be quite varied in the amount of wood that must be removed to get a close fit.  

 

So where’s the rub?  The more wood you have to remove to closely fit the pinblock to the bottom of the plate, the lower that plate will sit, since nothing can be done to shim it, the pinblock already being glued to the shelf.  It is not possible to set that plate to a standard height at given measuring points.  Likewise, for the flange fitting of the pinblock.  It’s already glued to the stretcher, so you cannot shim or remove wood to have the plate sit at a standardized location fore and aft.  

 

What do rebuilders do?  Assuming for the sake of simplicity that the old plate is well located and we want to accurately duplicate that position, we do several things.  First, we index the plate location by measurement or jigs to establish where we want to keep it.  Secondly, we start with a rough cut block that is too wide and too long.  Thirdly, we flip the plate over and fit the pinblock to the plate flange by grinding away the high spots, and do similarly to the bottom of the plate with the top of the block.  Then we joint the excess off the back of pinblock until the width is such that the plate will end up in the same position fore and aft.  We cut the ends off to our measurements, so that the side to side position will be retained.  If we want to make changes, we can plane off excess that will lower the plate as desired, and vary the side cuts to shift the block and plate to the bass or treble as needed.  We have a lot of control in achieving an intended result.  And we can glue the pinblock to the stretcher, the shelf, and rim sides, to achieve that “circle of sound” if we want to believe that folderol.  The block’s integration to the case I can accept, and I do a close fitting to achieve that.  The importance of that MAY lie in rigidity of retention, where the plate (in relationship to the rest of the superstructure)  minimally absorbs energy from the strings.  How much it affects that I cannot say.     

 

In contrast, our experience tells us that Steinway plate heights can vary considerably.  Most important, the height of the string plane varies.  Since Steinway does a standard bore on its hammers, then the varying plate heights can compromise the action geometry.  Likewise for the varying fore and aft position of the plate by Steinway’s method.  The factory partially accommodates that by where the action stack sits on the keys, and the capstan location.  And the effect on the action geometry is for better or worse.  And is generally worse since the factory stopped casting its plates. 

 

Most factories have traditionally fit pinblocks in somewhat the manner that rebuilders do.  I’m sure that Steinway has its reasons for doing things the way they do, but I’m not convinced that it is the best way to do it.  

 

Will Truitt

 

 

From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of Ed Foote
Sent: Thursday, May 03, 2012 8:29 AM
To: pianotech at ptg.org
Subject: [pianotech] making the Gen-u-whine Steinway

 

Inre the Steinway build procedures, Will writes:

 

I didn’t say perfect, I said better than what we see today and a better period overall.  And it is a factory nonetheless.  And they have always done some things I have never understood why, such as the way they fit the pinblock to the plate in the case.   And how they fit the action to that.<<

 

 

    The pinblock and stretcher assembly is installed as a structural beam that entrains a "circle of sound".  I was told at the factory, by someone who should know, that for acoustical reasons, the case should wrap 360 degrees around the sound board, but since that isn't possible, the block, stretcher, and bellyrail have to do the work, (with some help from the keybed.  They are part of the continuous containment philosophy. 

   I think the hard acoustical connection between pinblock and case is important to the sound, and since we are resisting the string vibrations in the the vertical as well as horizontal axis, the attachment to the stretcher assists in that. Another reason for them to be as integrated as possible.

 

       Taking that procedure, and throwing in a sand-cast plate, insures that every piano will be a little different.  I imagine that the plate fitting to the block is done this way so that the plate is fitted well on the  top and flange and the block's integration to the case is beyond compromise. 

      At one time, the actions were fitted by people that seemingly understood the whole interplay of caseparts/ratios/strikepoints , but that holistic approach seems to have been regimented out of existence.  

  

 

 Ed Foote RPT

http://www.piano-tuners.org/edfoote/index.html

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