Action Geometry

Kam544@aol.com Kam544@aol.com
Thu, 22 Jun 1995 14:16:46 -0400


Back on Tuesday I (Keith A. McGavern) asked:
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"Will someone please re-educate me as to the method of placing a string or
thread from the hammer flange center to some other action part to determine
appropiate alignments?"
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Since that time I have received basically two concepts:

Concept 1) If a straight line were drawn between the wippen flange center pin
and the bottom of the key at the balance point, the place where the capstan
and wippen heel cushion contact each other will pass through that straight
line.

Concept 2) If a straight line were drawn between the wippen flange center pin
and the hammer flange center pin, the place where the knuckle and the jack
tip contact each other will pass through that straight line.

Five pianos were used to test these concepts:
Baldwin Concert Grand, #91497, 1941
Steinway Grand D, #400653, 1967
Steinway Grand D, #382123, 1963
Steinway Grand M, #379569, 1962
Yamaha Grand C3, #F5333137, 1994

Concept 1) works proves true.
Concept 2) does not prove true.

Concerning Concept 2): Of the five pianos Yamaha was closest, Baldwin next,
then Steinway (not even close).  Can someone shed some light on Number 2)
please?

Keith A. McGavern, RPT
Oklahoma Chapter



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