Moment of Inertia of grand action parts.

[Richard Brekne]

Hmm... 

I dont really see why some useful and easy to implement method should be
too awfully difficult to work out John, tho to be sure it depends on
just what you are trying to do. That said there have been quite a few
points drawn out that allow themselves to be rather easily quantified or
measured. When thats doable, arranging these same on a scale gives a
reference from which purposeful planning can be drawn. 

That is essentially what Stanwoods system did. His so called equation of
Balance is simply a set of measurable parameters that fit into an
equation. Quantities such as Strike Weight and Front Weight have been
scaled on graphical charts in reference to that same equation. It all
adds up to a set of guidelines about static balance weight where a few
cause/effect relationships are clearly shown. There is little or nothing
in his formula per se that points to what SHOULD be. That depends
largely on what one is after to begin with. It DOES show you how to get
there once you've decided. Unfortunantly, it leaves out relevant
information and guidlines as to the subject of action inertia,
compliance, and other relavant overall ratios.

In anycase, I would not be a bit suprised to see a <<next step>> system
appear in the not to distant future.

Cheers
RicB



John Hartman wrote:
> 
> Richard Brekne wrote:
> 
> >
> > One of the things we are going to end up needing is a very clear and
> > simple way of measuring action MOI, comparing to a reference base ala
> > Stanwoods Smart Chart... or something in the same spirit, and choose
> > what hammer weights, ratio, and key leading will give us the particular
> > performance characteristics we are after at any given time.
> 
> Well Richard,
> 
> That would be nice but I don't think any simple process will come out of
> this adventure. I think getting the action reasonably accurate in terms
> of static balance is useful. It helps to make the action feel even at
> soft levels of play. Once the action is played with more force many more
> variables come into play and things become rather messy. To get the
> action to play from note to note perfectly evenly at loader levels we
> need to control things like the differences in key stiffness. Looking at
> the difference between the naturals and sharps I don't think that is
> going to be practical. I think the benefit to learning this stuff is in
> guidance with the relative importance of some of the thinks we do to
> actions. It will help to tell us what to pay attention to and what to
> leave alone.
> 
> John Hartman RPT
> 
> John Hartman Pianos
[link redacted at request of site owner - Jul 25, 2015]
> Rebuilding Steinway and Mason & Hamlin
> Grand Pianos Since 1979
> 
> Piano Technicians Journal
> Journal Illustrator/Contributing Editor
[link redacted at request of site owner - Jul 25, 2015]
> 
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