hitch pin glitch

[David Love]

About 65% of BP is usually the limit up there.  That puts your upper end not
greater than 54 mm or so (depending on whose formula you are using).  A
combination of too long speaking length plus a worn or sharp capo bar might
contribute to the net effect.  

 

David Love
davidlovepianos at comcast.net
www.davidlovepianos.com 

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Tom Sivak
Sent: Sunday, October 22, 2006 9:21 AM
To: Pianotech List
Subject: Re: hitch pin glitch

 

Joe,

 

What should the string length be?  

 

Are you suggesting the string length is too long, resulting in having to put
excess tension on the wire to get it up to pitch?  

This is only the second time I've tuned the piano.  I certainly didn't have
any trouble the first time, nor did the previous tuner, evidently.  I know
that the owner has kept the piano serviced regularly since purchasing it new
in 2002.

 

If it were a string length problem, why would it surface only now?

 

Tom Sivak

Chicago


Joe And Penny Goss <imatunr at srvinet.com> wrote:

Hi Tom,

I can't see how anything at the hitch would cause the string to tear at the
capo bar.

Measure the string length.

Joe Goss RPT
Mother Goose Tools
imatunr at srvinet.com
www.mothergoosetools.com <http://www.mothergoosetools.com/> 

----- Original Message ----- 

From: Tom Sivak <mailto:tvaktvak at sbcglobal.net>  

To: pianotech <mailto:pianotech at ptg.org>  

Sent: Sunday, October 22, 2006 7:21 AM

Subject: hitch pin glitch

 

List

I was tuning a 4 year old S&S Model S yesterday.  The piano was slightly low
in pitch, but not significantly, having been tuned only 6 months ago.  By
me.  

The string at C8 broke at the capo bar.  I was shocked.  I mean, this is a
practically new piano and it wasn't very flat.  

 

 I went to the car and got my string kit and replaced the string, spanning
the B7/C8 unison.  I started pulling the string up to pitch, going back and
forth between B and C, and finally got B7 in tune and went to C8, pulling it
up.  

 

I found B7 had slipped, alot, and pulled it back up, and found C8 had
slipped, alot, and pulled it up and back and forth and back and forth.

 

Something was wrong.  I continued to try to get the new string up to pitch.

 

Finally, the new string broke at the same place, right under the capo bar.
It was then that I noticed the plate hitch pin.  It was bent at a forward
angle, leaning towards the keys, unlike all the other hitch pins (with a few
notable exceptions, actually), which were all leaning back away from the
keys at about the 2 o'clock angle.  This hitch pin was at an 11 o'clock
angle.  I decided not to try to install another string with the hitch pin
looking like this.

 

I called the local Steinway dealer to initiate a warranty repair on this.
(I've never replaced a hitch pin, wouldn't know where to start)

 

My question is this: both strings broke.  It seems that the faulty hitch pin
must have had some play in this, but I can't see how, really.  How could the
hitch pin's angle cause the strings to break?

 

If I assume the hitch pin was in its proper position when I started to tune
the unisons (which I don't know, since I didn't look at it until after the
second string broke) and then bent forward as additional tension was added
by me pulling them up to pitch, I can understand why the strings kept
falling flat, since the length of the string, from tuning pin to hitch pin
was getting smaller.  But why didn't the string hold when pulled up to its
proper tension?  The string didn't slip off the hitch pin, it broke at the
capo when it almost got up to pitch.  

 

Could it be that the string started to move slightly upward on the hitch
pin, by virtue of the hitch pin's angle allowing it to do so?  If that were
true, then the string wouldn't render properly at the bridge, because of the
upward pressure against the angle of the bridge pin?  I'm really trying to
imagine how the hitch pin might have had a play in this.

I guess it's possible that the strings breaking were unrelated to the hitch
pin situation, but then why would the new string break?  Seems that it had
to have something to do with it.

 

Any ideas?

I don't think I will be involved in the replacement of this hitch pin, but I
am curious as to how it is done, and if it can be done in the customer's
home.  After finding the problem on B7/C8, I looked at all the other hitch
pins and found two others that are standing more vertically than all their
compatriots, as if they were on their way to moving completely forward like
the problem hitch pin did.  I could see the metal on the plate looked
'bunched up' on the front side as if the forward movement of the hitch pin
caused the plate metal to deform, slightly, upward, on each of the hitch
pins that were not at the same angle as the others.

 

Any comments?

 

Thanks,

Tom Sivak

Chicago

 

 

 

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