[pianotech] key leveling with a curve

Horace Greeley hgreeley at sonic.net
Fri Oct 15 01:47:26 MDT 2010


Hi, Dave,

At 11:30 PM 10/14/2010, you wrote:
>Sorry Al, neither argument seems logical, at least not at 2:00 AM.
>First, the idea that crowning the key level accurately anticipate 
>the settling of the keys is absurd.  Is that for a piano that;s 
>played heavily, lightly, or not at all?  And how much settling would 
>be taking place with half-rounds, vs. felt punchings?  David Love 
>pointed out the dilemma faced once any settling HAS occurred: do we 
>recrown? in which case we obviate the premise that we're doing it to 
>end up with a level keyboard. or do we pull out front punchings to 
>restore aftertouch.

Let's put this aside for the moment.

>As for any keybed radius... what are we talking about?  the entire 
>bed or the front rail?  Clearly the concept of creating opposing 
>curves to establish positive interface between the front rail and 
>the keybed  would apply to just that location: the front rail.  But 
>that's not where we establish key level.  The balance rail interface 
>doesn't depend upon flection to achieve positive connection.

There is so much confusion and misinformation about this that it is 
really frightening.

In a traditionally forefinished NY S&S (specifically, one in which 
the work has been properly done), there are multiple curved and 
planar surfaces.  That is, some are supposed to be dead flat (for 
example, the bottom of the trailing/back edge of the back rail of the 
keyframe and the area of the keybed on which it rests).  Others are 
supposed to have opposing convex radii (created by whatever means, 
but equal and opposing).  Still others are supposed to have opposing 
concave radii (again, created by whatever means, but nominally equal 
and opposing).  If you remember how Chris Robinson used to talk about 
pairs of opposing involuted curves in the action, you get a similar picture.

A part of the issue (and, not a small one) is that, as with so many 
other things in piano manufacture, things have changed a very great 
deal over time.  This is precisely why, at least as to NY S&S 
instruments, one size simply does not fit all when it comes to making 
things work.  While it is absolutely true that those who do 
substantive rebuilding have an opportunity to make some changes, even 
during that process, there are limitations unless one is willing to 
do things like completely replacing the keybed, change the frazing on 
the top of the inner rim, etc, etc, etc.  There are, as is often 
demonstrated on this list, a number of people who can and do do this 
kind of work.  Putting aside for a moment the whole range of 
discussions which then arise around whether or not something is 
"better" or is "still" a Yamawaisteinchickwinbechendorfer after such 
redesigning and rebuilding has taken place; most technicians simply 
do not have the time (even if they have the skill set) to do that 
kind of thing; and, even if they do, do their customers want or need 
that kind of work and can they pay for it?  Not everyone who owns 
tools falls into that rarified category; and, even if they do, are 
their customers willing to eviscerate the resale value of their instruments?

Believe it or not, this really is not off-point.  Without regard to 
how well or how poorly the forefinishing process is carried out on 
any specific instrument, it is a per-instance piece of custom 
work.  It simply is not going to be identical at all times and in all 
places.  Our job is to take each instrument as we find it; and, 
taking into account the overall situation of the piano, it's uses, 
owners, their budget, our skills, etc, etc, etc, come up with a plan 
to establish and maintain that individual instrument in the best 
condition in which it can reasonably be maintained.  Or, put another 
way, are we technicians, or are we new parts installers.

>The argument...she maka no sense!  but gets a lotta mileage.

With respect, the argument makes perfect and demonstrable sense.

The problem is that the whole forefinishing process has not been 
somehow actually publicly demonstrated with either sufficient 
competency or frequency for enough people to really be able to grasp 
what is going on during the process so that they have a better 
knowledge of how things (should) fit and why, and can better diagnose 
and treat issues as they arise.  Everything runs from deck height, as 
measure from the top of the keybed to the underside of the string at 
note 62.  To the extent that measurement is incorrect, everything 
else in the entire forefinishing process is compromised (beyond the 
state of compromise required for things to work even when that 
measurement is spot on).  This has been discussed at great length 
here a number of times before, so I'm sure there are a number of 
entries in the archives.

The importance of this latter is painfully obvious the minute one 
sits down to a "remanufactured" (e.g., "Heritage") instrument, and 
discovers that the damper system cannot be regulated because the 
blocks have been mislocated; and they have been mislocated because, 
in the installation of the new S&S/Kluge keyframe/etc, no attention 
was paid to actually fitting the new action to the existing keybed, 
let alone working at the same time to modify the existing keybed to 
mate properly with the new keyframe....etc, etc, etc.

Anyway...always more food for thought.

Best.

Horace
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