Striking Point

[Delwin D Fandrich]

Jerry Hunt wrote:

> . . . . Reblitz
> (which I refer to religiously) recommends striking distance of 1/7 of
> speaking length. However, I measured speaking length of C88, calculated
> 1/7th and compared to the old hammer , and it is considerably off. Way
> more than the slight difference in the new flanges, but looks reasonable
> compared to what I am used to seeing on verticles; i.e. around 1/8"
> below the v-bar.

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Reblitz is off on this one.  For decades the myth of the 1/7th strike line has
been floating around.  I've never encountered a piano that actually had the
hammers striking the strings 1/7th of the distance from the front termination.
There might be some early instruments in which this was the case, but Stephen
Birkett would have to comment on that.

Typically the nominal hammer strike point in the "modern" piano falls within a
range from about 1:7.75 to 1:8.25.  Occasionally this will go up to as high as
1:8.5 on a very small piano.  This ratio will more-or-less hold through about
the middle of the scale.  From there through the high treble it will shorten
until it reaches approximately 1:12 to 1:16 at C-88.  These numbers are not
locked in cast iron.  This theoretical strike point often varies quite a bit
within the piano, especially across the bass/tenor break and through that part
of the grand plate that uses a cast-in v-bar underneath the capo d' astro bar.

Through the high treble it becomes very difficult to pre-set this with any
degree of accuracy -- it's a lot easier to do on paper than it is in the piano
-- hence the adjustable keyframe pin plate in the treble keyblock.

In your old upright the strike point at C-88 will probably end up being about
3.5 mm (0.14") from the V-bar.  At least that would be a good place to start.
You can usually fine-tune this by raising or lowering the action slightly.

-- ddf