M&H Screwstringer

[RobertD429@aol.com]

Ever since the Mason and Hamlin screwstringer discussion last month, I've
been thinking about why they died out. In addition, some of my more inventive
clients have asked why the piano doesn't have some sort of a geared tuning
system instead of the more "primitive" tuning pin.

Surely the screwstringer tuning screws, made in quantity, would be no more
expensive to manufacture than the tuning pin/pinblock assembly; perhaps less.
I think their disappearance is not so much an indictment of the clever
screwstringer mechanism as it is a tribute to the simple elegance of the
tuning pin.

Gordon Large mentioned the uneven rendering on a neglected screwstringer
which made tuning difficult and time-consuming. This can also be found on
tuning pin-equipped pianos with high friction or corrosion at the front (or
top in verticals) bearing/counterbearing points. The friction can be reduced
in either system. One could even imagine a modification of the screwstringer
system which would eliminate these points entirely. Since the screw is a
shallow ramp, it would permit (as Jim Harvey says) a very fine adjustment of
the vernier sort.

In neither case, however,  would it be advantageous to reduce friction to
zero. With the tuning pin system, it would be almost impossible to get the
necessary accuracy without friction. In a system with direct suspension of
the strings there would be a practical difficulty of getting unison strings
exactly the same, correct length to maintain control over their
inharmonicity.

In the ideal tuning of a string, everything is in equilibrium; that is, the
tensions on the short segments of wire equal that in the speaking length.
This would be practically impossible, at least with a tuning pin, because it
would require a fineness of rotation so small as to be unattainable. Without
friction, the tiniest difference would equalize immediately. While we could
then easily know when we were wrong, the friction gives us the tiniest bit of
grace -- if the tension on the speaking length is correct, the pitch can
still hold even with a small difference in tension in the front section of
wire.

Of course, tuners whose tunings are the most stable are able to keep this
tension difference to an absolute minimum by "feeling" where the "center" is
between overcoming the friction to the downside and overcoming it to the
upside. This is done with very quick flexing of the pin to the upside and
then to the downside (without rotating  or bending it) and can be done, even
several times, in the blink of an eye. In the screwstringer, while the
initial setting of pitch in the speaking length is easy, the "feel" of when
the tension is right in the short front segment is MUCH slower (and in my
opinion less accurate) than with a tuning pin. That is why it seems more
necessary to get the stability by pounding, which, while it works, is
inefficient.

Bob Davis, RPT