[pianotech] String breakage

[Matthew Todd]

I am reading all these comments with great interest, thanks!


TODD PIANO WORKS 
Matthew Todd, Piano Technician 
(979) 248-9578
http://www.toddpianoworks.com

--- On Wed, 3/3/10, David Love <davidlovepianos at comcast.net> wrote:


From: David Love <davidlovepianos at comcast.net>
Subject: Re: [pianotech] String breakage
To: pianotech at ptg.org
Date: Wednesday, March 3, 2010, 3:15 AM








I don’t think the bends weaken the string any significant amount.  Why would it?  Wire bends, it isn’t particularly brittle.  The breaks that occur at the bends are more often due to friction at the bearing points and increases in tension in one segment when the wire doesn’t render through those points easily, not because of the bend itself.  
 
David Love
www.davidlovepianos.com
 

From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of pnotnr at aol.com
Sent: Tuesday, March 02, 2010 6:49 PM
To: joegarrett at earthlink.net; pianotech at ptg.org
Subject: Re: [pianotech] String breakage
 

Thanks, Joe

You're right about the typical breaking %, but my point was just that the bends we put in the wire are weak spots and are closer to the breaking point.  So that even though the Mason & Hamlin 9 foot string AO calculation you mentioned puts it at 75%, the bends in that string must be closer to 100%.

Gordon Large, RPT
Maine

 

 

 

-----Original Message-----
From: Joseph Garrett <joegarrett at earthlink.net>
To: pianotech <pianotech at ptg.org>
Sent: Tue, Mar 2, 2010 5:01 pm
Subject: Re: [pianotech] String breakage


Gordon said: "When a string is at pitch, it's usually around 60% of the tension that would cause it to break."

 

Gordon,

That is a false statement for the most part. Most strings are in the 35% to 55% of breaking strength @ pitch. There are exceptions, but are generally few and far between. Most Yamaha scales are "High Tension Scales", so you will find that string breakage is more common, especially with the U.S. made versions. The example of a 1900 So/so Grand and how far one had to twist the t.pin to get the string(s) to break, was an example of a Medium or Low Tension Scale. 

Just FYI, the thicker the soundboard and the stiffer the soundboard assembly is, the higher tension and the harder the hammer is required to get decent (?) sound production. The best example of a string that WILL break, is the M & H 9footer - A0. That string is at around 75% of breaking strength, at pitch and WILL break. (Soooner than later! <G>)

Regards,

Joe

 

 

Joe Garrett, R.P.T. (Oregon)

Captain, Tool Police

Squares R I

 

 
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