[pianotech] Tuning the duplex sections

[John Delacour]

At 20:25 -0800 12/03/2011, Delwin D Fandrich wrote:


>Another important factor which is, if I recall correctly, mentioned in the
>old patents is the benefit to the tone and longevity of the string from
>changing the wire movement at the capo from a bending action to a pivoting
>action.  When the duplex length is short or the angle very steep, the wire
>is effectively locked down against the capo.  When the angle is lower and
>the length is longer, the wire can rock or pivot slightly on the capo,
>reducing stress on the wire.

In the very old days English and German pianos, at least, had a 
sloping wrestplank.  The angle of the slope was 8° and so the string 
did not bite into the bearing cloth but went straight from the pin to 
the agraffe at that angle, the bearing cloth serving as hardly more 
than a damper.  I haven't measured exactly the angle on the fine old 
Blüthner uprights with no pressure bar but it looks very similar. 
Nick G. was talking of 15° and 18°.  What would be the need of such 
steep angles?

JD