string height

[Delwin D Fandrich]

David,

There are other reasons for this style of capo-'d-astro bar as well as those you
mentioned. It allows the builder better control over the location of the V-bar for one.
This is less of a factor today since V-bars can fairly easily be milled to shape and
position using CNC equipment. In the "good old days" the location of the V-bar could vary
quite a bit as the pattern aged.

I would guess that the piano builder was trying to match the elevation of the front string
termination to the anticipated crown of the soundboard. Or some fraction thereof. It is
also possible that the hitch pin panel is crowned in somewhat the same manner.

A variation of 6.0 mm is a bit much, but I've seen much more. Usually the variation can be
compensated for by simply adjusting the hammer line. Occasionally, when new hammers are
being installed, it is desirable to alter the hammer boring dimension to compensate.

-- ddf

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David W. Pitsch wrote:

> Concerning new grand pianos made in Eastern Europe with a screw on
> D'Capo Bar in the top two treble sections.  I have been taught that the
> reason manufacturers use this type of D'Capo is to get away from the
> problems associated with a plate casting (too thick or too thin, air
> pockets, etc.), and to keep the tolerances as close to blue print as
> possible.
>
> Much to my surprise I found the string heights to taper from 21.4cm to
> 20.8cm at note 88.  This makes for an interesting regulation and
> voicing.  Going on and measuring the string heights in the plain wire
> agraffe section came out at 21.1cm tapering to 21.4cm!
>
> Anyone else seen this much variance in string height?  The hammer boring
> is a consistent 2 1/16" (5.24cm) throughout the plain wire sections.
> These pianos are described as "hand built"!  Contacting the
> manufacturer's technical representative about this problem, the answer
> was rather evasive.