Grand action geometry

[stanwood]

>In manufacturing, we can reconsider the position of the balance rail, and
>thereby the key ratio.  In the field, this is pretty much out of your
>control, unless you wish to plug and re-bore the balance pin mortises.  It
>is conceivable that field tech's could plug and re-bore the capstan

Dear Frank,

Some comments...

The piano action is a lever that throws a weight.  To define the basic
nature of the forces required to play a piano action you need to define the
weight of the hammer and how fast it moves in response to the key.

I move capstan lines whenever the leverage is not what I want it to be.
(Assuming action spread is correct and the capstan/wippen contact is on a
line between the wip center and the key balance point).  Aproximately 80% of
my rebuilds require moving the capstans in order to offer my clients uniform
leverage standards.

The way I determine leverage is by association with weight ratios that can
be measured using touchweight analysis techniques.  Specifically, knowing
the ratio of hammer weight to its upward effect at the key gives you an
indication of action leverage.  The higher the ratio, the lower the leverage
and vice versa.

I will repost "Strike Weight/Ratio" for those new to the list that missed.
I can't repeat it too many times.

David C. Stanwood