> On an older piano the strings are pretty much stretched so the
> only reason for the piano going flat is plate compression and
> case deformation.
I would like to clarify this statement. I was referring to the
piano going flat during a pitch raising, not the loss of tension over
a period of time.
Pulling the pitch radically sharp would cause string leveling problems
once the tension is lowered. Raising the pitch enough to deform the
string has no benefit at all.
On the subject of wheels, those are thought to put too much downwards
force on the string and crush the bridge surface. Rubbing the wire on
the back scale and speaking length with a hammer shank or something
similar is preferred.
Once a newly strung piano is at tension and tuned for about a week,
removing the natural curve from the wire at the bearing points will
improve the tuning stability. It will also improve the tone by better
defining the termination. Start at the hitch pin and squeeze the
wires, then tap the wire at the rear duplex (wooden dowel or brass
punch). then remove the curve at the bridge pins.
To improve the termination at the agraffes and v-bars, I use a lever
which has a spinet caster mounted. The wheel rolls on the wire. Lift
the section in front of the v-bar first, then the speaking length.
Then tap the wire both sides of the counter bearing bars. This
procedure usually drops the tension by a quarter tone or more. Pitch
raise and tune. The piano will stay in tune longer (for new strings)
and sound better. Doing this procedure on older pianos improves the
tone. String leveling and fitting to the hammers is next.
So I would say that it takes about six passes to get a newly strung
piano up to pitch with a stable tuning.
Jon Page, piano technician
Harwich Port, Cape Cod, Mass.