Optimizing repetition

[Jon Page]

At 11:00 AM 4/15/97 -0500, you wrote:
>That is, the jack at rest is a lttle more away from the
>player than we normally think it should be.  The variation is not so
>much that the jack doesn't perform as normal and it will pass all the
>above tests.  Assume all else is equal and the jack will be moving the
>exact same distance as it would with the normal adjustment specs.  But
>after it is tripped, it winds up a little closer to the knucle than
>normal and is just a little more ready for the next repetition.  I am
>not trying to change the standard specifications for regulation with
>this tip.  It just works well when preparing a grand action for someone
>who likes super fast repetition.
>Joel Rappaport

Joel,
I don't see how moving the jack back will bring it closer to the
knuckle when tripped. It will just drag it thru more distance; and
places it in contact with the letoff button sooner causing resistance
sooner in the key stroke increasing the letoff 'window'.
Once the jack is tripped and the hammer checked in, the only
influence on the relative postion of the jack to knuckle is
key ratio (given a set key dip, letoff, hammer length/height and
knuckle radius).
The further back the placement of the capstan, the further the jack
is from knuckle at key stroke end.  Some pianos have the jack burying
into the stop felt at the end of the repetition lever. By moving the capstan
(and sometimes the whippen cushion) forwards, the travel of the whippen
is decreased (also lightens the touch), therefore the jack is in closer
proximity
to the knuckle at the end of key dip.

I have seen the jack being thrust so far as to hit the hammer flange. Also
being wedged between the letoff button and the stop felt, it has restricted
the key from going to the bottom of the key dip.




Jon Page
Harwich Port, Cape Cod, Mass. (jpage@capecod.net)
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