[pianotech] pitch and temperature

[Ron Nossaman]

On 1/9/2011 8:57 PM, Gene Nelson wrote:
> Thanks everyone,
> I was trying to come up with a chapter technical on the subject.
> Possibly an approach from co-efficient of expansion for steel piano
> wire, isolating for the one thing that moves the fastest and possibly
> the most? The math is beyond me.

The math is pretty simple, and I'm math deaf. The expansion coefficient 
of music wire and gray iron are pretty close. The difference is in the 
cross section of the parts. It takes little time for a temperature 
change to migrate through 0.040" diameter wire compared to 0.5" iron. 
That's it.


> My challenge was a couple years ago in the winter, a loaner sat on the
> moving van in freezing weather overnight, brought on stage indoors in a
> warm theater and I had about an hour to work with it.
> Gene

There's the problem. The strings changed fairly quickly, maybe up to 
half way through the tuning, where the plate caught up about four hours 
later. This is an impossible situation, and any tech who hopes to 
anticipate the changes and accommodate them to all come together in a 
good tuning at a specific time is eligible for a really good land deal I 
have available in Florida.
Ron N