S&S "S" Treble wire

[Mike and Jane Spalding]

Paul,

I have heard about this problem from other techs.  Apparently it is in the design of the S, and varies from piano to piano only in the amount of inconsistency in Steinway's manufaturing process.  2 3/8 is more common than 2 1/2, allowing a little more time delay before the strings break.  Almost any other piano will be in the range of 1.95 to 2.05 at C88.  That extra 1/2" of string length increases the tensile stress in the wire from a tolerable 185,000psi to an intolerable 285,000psi.

Changing wire diameters will have negligible effect on the breakage.   At the same pitch, the larger wire will be at a higher tension, which offsets its higher strength, i.e. inernal stress will be within a couple percent of being the same.  If you were rebuilding the piano, you might shorten the speaking length enough to get into a safe stress range, by moving the plate towards the back, and moving the front bridge pins closer to the front of the bridge.  The only other possibility I can think of is to find a wire made from higher than normal strength steel, but I have no idea if such a wire is available.

Mike Spalding RPT


----- Original Message ----- 
From: Paul McCloud <pmc333@earthlink.net>
To: <pianotech@ptg.org>
Sent: Tuesday, October 22, 2002 1:31 AM
Subject: S&S "S" Treble wire


Dear Friends:

            I am having a dilemma with a Steinway S in the highest 2
treble strings.  I can't seem to get them to pitch without breaking.
I've tried using emery cloth to smooth out the V bar.  No luck.  I've
lost count of how many times I've tried different strings.  I'm
beginning to suspect the length of the strings in the speaking area is
too long.  I've measured the bridge pin to V bar on the B7note to be
very near 2 ½ ".  Is this usual?  Other Steinways have lengths of 2 ¼"
or less for the same note.  In our store, we have just this one "S".
It's about 15 years old.  Would it be advisable to go to a 12 ½ gauge
string instead of the 13 which is labeled on the plate?  It seems that
the breaking strength of the wire is too close to the tension necessary
to get the note to pitch.  Help!

            Thanks 

            Paul McCloud

            San Diego