BREAKING STRINGS

[Susan Kline]

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