Action Geometry

[Vince Mrykalo]

> Date:          Thu, 22 Jun 1995 19:10:13 -0600 (MDT)
> From:          David Porritt <dporritt@sun.cis.smu.edu>
> Subject:       Re: Action Geometry
> To:            Multiple recipients of list <pianotech@byu.edu>
> Reply-to:      pianotech@byu.edu

> > 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
>
Concept two is not correct.  That line should not be broken by the
knuckle/jack contact point, but only approached, and at let-off be
very close to, but not above, the line.

---
Vince Mrykalo  rpt

Wish to be considered to know nothing: and if you shall
seem to some to be a person of importance, distrust yourself-
Epictetus