Spring fever (or feverish springs)

[Delwin D Fandrich]

Vince Mrykalo wrote:

> Del, what did you do to the action geometry?
>
> Vince Mrykalo RPT
> ~~~~~~~~~~~~~~~~~~

Well, it was pretty crude in those days.

Generally it was a result of Steinways habit of allowing the action stack to float around
on the keyframe. The front of the keyset is aligned to the front of the piano -- either
the front of the arm or the front of the keybed. The plate does not have a fixed
relationship to the rim and the action -- with its hammers already installed -- is aligned
to the plate. This means that there is no fixed relationship between the capstan line and
the key balance point. The overall action lever ratio was -- perhaps still is? -- a
variable that was compensated for by adding more leads. For a while we were getting M's
and L's with six to eight leads in the front of the keys. There were even two+ leads
through the treble section of a couple of pianos. Usually by remounting the action stack
slightly and plugging and moving the capstans I could come up with a lever ratio that was
more suitable. Generally I tried for a maximum of four to five leads in the low bass. More
than I wanted, but a lot better than the original.

By the way, this whole exercise points out the fallacy of "individually weighing off" keys
for even touch weight. In my view this is a terrible practice. Especially when done by a
factory. Key leading should be done to an engineered standard. If the "touch weight" does
not then meet the factory design standard, the reason why it doesn't meet the standard
should be determined. Usually it will be due to some deviation from the design back down
the line. Either the geometry is off, there is too much friction in the system, or
something. The solution is not to simply add more lead. Or to move the leads around.
Sooner or later the friction problems are going to be discovered and fixed. Then what? If
an extra lead has been added -- or perhaps they have been moved closer to the front of the
key -- to compensate for excessive friction you're now faced with the task of removing the
extra lead and doing something with the hole. Not good. Action geometry is not that
sensitive that factory leading cannot be done to a standard if reasonable checks and
inspections are carried out to insure that the actions are assembled the way they are
supposed to be assembled.

This practice is often highlighted as a "feature" in a manufacturer marketing story as if
it somehow makes the piano "better." When I see it I immediately have to question how much
control that factory has over their action assembly and regulating processes.

-- ddf