Re action Geometry

[PSLOANE@OCVAXA.CC.OBERLIN.EDU]

------------------ORIGINAL POSTS----------------
At  9:55 AM 7/10/95 -0600, Kenneth Sloane wrote:
Those are great questions Richard. Bring them all to the CAUT Forum where we
>can get into them much more thorougly and with several opinions aired.
>However, just to comment briefly about actions varying. Steinway has for years
>slid their hammer action on the key frame to accomodate strike point, creating
>pianos with different key ratios. My suspicion is that the varying key ratios
>created much less problems in the "good old days" because hammers were
>lighter. Unfortunately, a heavier hammer is not so forgiving to pianos with
>"leverage" problems. However, this is just a beginning to what should be
>discussed.



__________________________


      Our different, and sometimes opposite perspectives on geometry really
are fascinating. Previously I suggested that "some" technicians might use
the high leverage Hamburg shanks because they are more forgiving of other
problems. Now Ken points out that light hammers are more forgiving. In
fairness, I think that perhaps neither is really correct.  Rather, when
heavy or light hammers are correctly mated with the high or low leverage
shanks respectively, it is a wash. I find that switching leverage parts
from low to high with the same hammer will reduce DW about 5 grams.  Or
conversely, if switching parts from high to low leverage on the same hammer
I will need to reduce about .8 to  1.0 grams of hammer weight to achieve
the same touch weight.  None of these variables should be viewed as an
adjustment to compensate for geometry problems, but I'm sure that this is
not what Ken meant to imply.

        I am regretting more and more that I will not be in  Albuquerque
this month. Ken, do these two actions you fitted to the same piano
represent both the low and high leverge styles? That is probably something
you intend to discuss, and it would be very interesting to hear your view.
Hopefully someone will post us a review of the forum. I must admit that I
am still not convinced that there isn't a significant price to pay in
inertia for the higher wattage of heavier hammers, even when the strike
ratio comes out the same, so I look forward to David Stanwood's book
whenever this comes out. Is maximum tonal energy ALWAYS our primary
objective anyway? Have we completely lost touch with our pianistic roots?
When this discussion started some months ago I understood there to be some
agreement that these actions do feel different somehow. Perhaps I
misunderstood, but this question has certainly opened up again with
different views and it should be a lively discussion in Albuquerque.
         What happened to the Yardbird?




Dennis Johnson
St. Olaf College

-------------------MY REPLY------------------

I would characterize the two actions as such:

Old action -- medium leverage
Old action -- medium leverage

I don't have the time right now to get into specifics, but I'm sure the
occasion will present itself in the future for that. I just want to clarify
what I meant about light hammers being more forgiving. The weight of the
hammer plays a big  role in contributing to the inertia of the action. Even
with low leverage, a piano with  light hammers can still have a relatively
light touch. However, a piano with heavy hammers and low leverage, watch out.
Here comes the tendonitis.

L
Ken Sloane, Oberlin Conservatory

new action -- high leverage