[CAUT] Wire Stretch, was Hardness of termination vs string breakage

[Jeff Tanner]

Ron Nossaman wrote:
>>  I'm still of the opinion that
>> most of the pitch drop we see in new pianos and rebuilds the
>> first year is from the cap crushing at the notch edge, perhaps
>> some from pinblock compression at the flange, and very little
>> of it from string stretching.

On Apr 18, 2007, at 9:41 PM, Fred Sturm wrote:

> My own take is that most of the pitch drop comes from the string  
> conforming
> to the angles it is forced to go around. Creating positive bends  
> (pressing
> against the string with a sliding motion) at each of those points  
> hastens
> pitch stability considerably, in my experience. Most new pianos  
> don't get
> that treatment, and so you find that high treble notes will go 100  
> cents
> flat through vigorous pounding.

The last few days has me thinking about these statements.  I realize  
what I am about to throw into question is not about new wire, but I  
am curious just the same.

If plain wire does not stretch as much as we traditionally give it  
credit, how would one explain the great difference in pitch change  
from wrapped wire to plain wire as changes in humidity affect tension  
change?  Not just crossing from bass into low tenor, but it is just  
as much present when the first few strings of the low tenor are wrapped.


Jeff


Jeff Tanner, RPT
University of South Carolina



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