M&H Screwstringer

[Mike Cook]

----------
From:       RobertD429@aol.com[SMTP:RobertD429@aol.com]
Sent:       Wednesday, September 27, 1995 7:14 AM
To:   Multiple recipients of list
Subject:    Re: M&H Screwstringer

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.=20

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.=20

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.=20

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

Bob,
I am the newsletter editor for the Indianapolis chapter PTG.
I found your posting intresting. I wonder if you would mind if I were to =
print it in our next newsletter. I think our chapter would enjoy it.

Mike Cook
269 N. Wayne St
Danville, In  46122
E-Mail  A440@iquest.net