I think D.L. Bullock would be interested in a book called "Piano
Rebuilder's Handbook of Treble String Tensions and Other Characteristics."
It is complied by James H. Donelson and is probably still available.
In this book is a computer-generated listing of all sizes and lengths
of treble string used in a piano. Of particular interest is the wide
range of tensions found on piano strings for any given diameter, as
well as the "inharmonicity" content of the 2nd partial of these wide
ranges of combinations. Also given in the list is the string's percent
of tensile strength used. That is all you need. Study that, and it
should answer all the questions regarding the possibility of
"overstretching." For instance, a 13" long wire of .0380 diameter and
134 pounds tensions plays about 523 Hz. The same wire size, but 39.37"
long, strung with 249.54 pounds plays at 220 Hz. That still is only
62% of its tensile strength, well within the limits of its modulus.
But, do these facts mean anything to most tuners? I don't really know.
Young's modulus resides within and is determined by the tensile
strength, or the string's elastic recovery, which, as we said, is a
constant. It's just like a spring, which is not yet overstretched;
overstretch a spring and when it returns it is elongated. The same
happens to piano wire. I used the word "extrude." That is a
legitimate term also. So when a tuner tunes piano wire 20 cents sharp,
it is far from exceeding the tensile strength of any string in the
piano. 20% of the frequency is not 20% more tension. Most pianos are
strung to approximately 25% to 50% of their strings tensile strength.
The longer the string for any given diameter, the less inharmonicity it
will contain at the given frequency it is tuned to. I don't intend to
go deeper than this; look it up if interested. "False beats" are not
caused by "hard places in the wire," or overstretched strings.
Over-stretching is only done very occasionally by accident by
experienced rebuilders, and never on purpose! But overstretching a
string at the moment it is overstretched will cause it to break,
usually at a sharp bend or point of contact; it will not "tire" the
string so that 50 years later it breaks. "Rotten" string (as some call
it) is caused by either faulty pickling in the process of making it,
or a temperature excursion during the annealing process. It is nothing
that the tuner has done to the string himself. It often has to do with
the surface of the string becoming granular with age. But even bad
wire will not itself create false beats, even though a restringing may
solve the problem. Many other changes must be made at the same time.
Regarding the number of tunings to a new piano, they vary. A new
piano requires multiple tunings, but I've not heard they require six.
It doesn't matter anyway; it's entirely a moot point. Remember that
new wood is still moving and shrinking and compressing, and the joints
are settling, and moisture is redistributing. It's like a new violin
and its many new startup problems.
We here are not speaking of new pianos, but 70- to 90-year-old pianos.
That's a different ball park. Also remember that, today, some new
pianos never do settle down because of time-saving techniques used to
cure the wood faster. Just as homes today creak and groan with the
seasons, old wood didn't used to do that when it was racked and then
framed and seasoned for five years outdoors. It is due in part to
quick seasoning techniques, and possibly in part to the fact that Sitka
spruce of northern forests may not be used any longer in all but Yamaha
piano soundboards and companies able to buy from them. By now, the
old soundboard wood stored for so long by so many piano companies has
probably been used up or is almost, and I understand that different
species of spruce are being added to the mix now. These are not as
strong, and the boards have to be made thicker to withstand the same
downpressure. Those pianos then which use the same thickness, not
accounting for the different grades of material, will compress greatly
in the center in the instruments having a little more downbearing (and
it doesn't take very much of that to make a huge difference) and not
hold a good tune for perhaps years later.
I would forget worrying about what happens to strings when they are
overstretched, unless you are new to the business and might likely
break strings accidentally, and concentrate of other things, like D.L
iterated in his list of things to do when a piano is strung. Those are
all good and necessary techniques. Stick by the basic principles and
don't imagine things that aren't really happening anyway. Let the
molecules in the wire do their thing, because they do stick to the
principles. The fears that D.L. has about overstretching strings is
very common, and those fears are not easily removed.
When I mentioned the story about Dr. Hickman's experience with an
electric drill and he was corrected by an experienced technician to
"always use a hurdy-gurdy hand drill because an electric drill would
ruin the tone," do we think that all of Dr. Hickman's equations and
logic would have made one centimeter's difference in that fellow's
opinion? No. That's what opinions are good for. They anchor us
firmly against the forces of scientific proof and all physical facts
to the contrary. We therefore stand uncorrected and unmoved. As
an interesting aside, Robbie Rhodes then told the same story on a
modern-day Boesendorfer factory technician having said the same thing.
It doesn't matter who says it, including piano manufacturers! Just
remember, if Kimball used to make pianos, that proves there are lots
of differing opinions out there, and all opinions masquerade as facts.
The facts are the physical principles, and few people like them very
much. But then, that happens to be a fact, too.