BREAKING STRINGS

[Jim Coleman, Sr.]

Hi Leslie:

I sure looks like the replacement strings should have had less copper wrap
(ie, smaller diameter). When strings break at the bridge pin, it is most 
likely too high in tension. Newton can give you the specifics if you post
to him the specs.

Jim

On Sat, 20 Feb 1999, Leslie W Bartlett wrote:

> Oops, sorry, this is a Beckendorff piano, upright, about twelve years
> old. Actually not a bad sounding piano. But it's the first wound string,
> and must be replaced with such. It originally broke in the wound section
> from corrosion, perhaps mouse pee.  So, it had a wound string on itat one
> time.
> 
> The string broke at both replacement attempts at the bass top bridge pin.
> 
> lesb
> 
> 
> On Sat, 20 Feb 1999 10:13:47 Susan Kline <skline@proaxis.com> writes:
> >Wow, Les, hot from the press! You don't wait around. You don't say
> >what type of piano this is, or what age. I would guess that it's 
> >a quite old piano, probably of an obscure brand?
> >
> >I once had something similar happen, when replacing bass strings
> >on an old upright, at the top of the section. In the first two
> >or three notes there were several broken strings, including one
> >replacement. I put a new string in, and it felt very tight coming
> >up. I barely got it to pitch. I put another in, and it broke.
> >
> >At the house, I measured the speaking length as well as in the
> >core and wrap diameters, and plugged them into PScale (Tremaine
> >Parson's program) when I got home. The speaking length was too
> >long, and there was no wrapped string size which would yield
> >a safe tension as a percentage of breaking strength. When I 
> >gave up on the wrapped wire, and started trying plain wire,
> >I found a decent set of numbers at size 19. 
> >
> >I went back to the piano, put in the plain wire, even though it
> >was in the bass section, and the notes sounded fine and the strings
> >didn't break. 
> >
> >In this case, the old designers just had guessed wrong.
> >
> >Susan
> >
> >-------------------------------------------------------------
> >At 12:36 PM 2/20/99 EST, you wrote:
> >>I am writing this from the home of a customer where I have  
> >encountered a
> >>problem I can't figure out.  She had a broken string, in the winding, 
> >due, I
> >>think, to mouse pee. I ordered two strings, one for the broken one, 
> >and the
> >>other for one which looked like it would break soon.
> >>
> >>The new string broke before I got it to pitch.  I chalked that up to
> >>stupidity.  The second string also broke before I got it up to pitch. 
> > This I
> >>don't credit to stupdity. I cannot find a burr at the pin on the top, 
> >and the
> >>angle of deflection isn't radical. I got it within half a step, then 
> >was very
> >>careful about going toward pitch.  I even lubricated the friction 
> >point,
> >>trying to be over-cautious.
> >>
> >>I measured accurately.  First time I used a snap guage. Today I 
> >remeasured
> >>with a micrometer, and got the same readings.
> >>
> >>Any wisdom????????????   If the reply is posted to the list, I guess 
> >you
> >don't
> >>need my e-mail. It's included in case anyone answers me privately.
> >>
> >>Incidentally, the lady asked me, "By the way do you do plumbing?  We 
> >called
> >>"JM" plumbing and they want $200 to install a garbage 
> >grinder......... "
> >So, I
> >>spent 30 minutes putting the new one, she going after the new tubes 
> >etc. and
> >>made a few extra bucks........
> >>
> >>les bartlett
> >
> >
> 
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