Tuning old Chickerings

Jim Coleman, Sr. pianotoo@IMAP2.ASU.EDU
Thu, 13 Jun 1996 17:34:27 -0700 (MST)

Dear Vince and Dan

I agree with Vince.  I've been a jerk or a jerk tuner for many years.
I have had minimal breakage, but less since I began being a jerk
tuner.  Here is my reasoning:

After doing many tests in the lab while I worked at the CG Conn Co. in
the research and design division,  we learned that just before a string
breaks, it begins to "neck down".  This takes a finite amount of time as
tension remains constant.  When a string breaks as we are tuning, it most
often breaks at the point where it begins its coil around the tuning pin.
Since the most common cause of breakage is that the string is stuck at
the V-bar and the segment of wire from there to the tuning pin is at a
much higher tension than it is in the speaking length, the string breaks
where the greatest stress is located.  That place is most often at the
tuning pin.  Strings break at the V-bar or the bridge pin only when there
has been some previous weakening there caused by extremely heavy playing.
On rare occasions a string may break at a bass hitch pin or at the front
end of the loop where there is greater stress

As one uses the smooth pull tuning method, there is more time in which
the string sustains the greater stress at the tuning pin.

Forty years ago I was restringing a large Steinway A which has 10 strings
in the tenor section.  These strings were made by a company which did
not have the Steinway specs.  As I began pulling.a string up, the tone
was rich and bright.  By the time I got it up to about a quarter step
flat, the tone began to go dull.  As I continued to pull it up, it just
stayed there, and when I left it alone, it finally necked down so much
that it broke.  I repeated this on several strings (you show me something
5 times and I will get it right off) until I realized that my strings had
too much copper and not enough core diameter.  I got Steinway to airmail
me a set which arrived the next day.  We were only one day late on
delivery the next week.  I put this story in here to show that I really
do know what necking down is like.

In the Conn lab we had a setup where a tension gauge was attached to the
loop end and the other end passed over a bridge and then 90 degrees down
over a ball bearing pulley where a weight was attached.  We would add
weights until we could see and hear the yield point, after which the wire
would begin to neck down and eventually break at the weight clamp.

On very old pianos like Chickering, Emerson, Ivers & Pond, and tall Knabes
which are all high tension scales, you will find more breakage.  Sometimes
there is corrosion at the point where the string begins its coil around
the tuning pins.  If this corrosion is hard enough it can cause a sharper
bend in the wire as the pin turns.  In this situation it is wise to knock
the pin back before pulling (oops, jerking) the pin up.  I tune from a
2:00 o'clock position to a 3:00 o'clock position on vertical pianos if
possible.  This decreases breakage as follows:  As the pin is turning, it
is also dipping down.  As it springs back up, it then raises the pitch.
Two different things happen in rapid succession - turning first, then
lifting.  When one uses the smooth pull method on a vertical piano, the
pulling up of tension and the turning of the pin happen at the same time,
plus it it necessary to raise the pitch above where you want it in the
end.  Also, the extra tension is applied over a longer time segment, thus
increasing the possibility of breakage.  The jerk method at 2:00 o'clock
position requires less over pulling (jerking) of the pitch, hence less
time at an extreme tension and consequently less breakage.  Try it, you'll
like it.

Jim Coleman, Sr.

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