Tuning For Pitch

[Greg Graham]

Philip Jamison wrote: 

"How much does a robust A440 tuning fork vary in pitch
with temperature?"  See answer below.

I would ask: How much does a robust piano vary in
pitch with temperature? More than the fork, from what
has been reported on this list.

I've read you should place the fork on the piano's
plate while you get your other tools ready.  The piano
and fork will be at the same temperature.  If that
happens to be 95 degrees or 55 degrees, both will be
"off" in the same direction.  The question is, how
much different?  

I have a very common blued steel John Walker fork
which I calibrated to A440 at 75 degrees F.  When
placed under my arm for a few minutes (85 degrees?
90?) it reads 1.39 cents flat. After 5 minutes in the
kitchen fridge (35 degrees?) it was 2.87 cents sharp. 
Five minutes on a table (75 degrees), it still felt
cold on my neck, but was just about back at 440, only
0.14 cents sharp.

I also have a slightly shorter, slightly stockier
chrome plated steel fork with a round ball on the
handle which is labled only "Germany" and "440".  I
don't remember where it came from.  It is also set at
440 at 75 degrees, but the "armpit-ch" on this one is
1.52 cents flat.  Five minutes in the fridge, it was
1.58 cents sharp.  

Know thy fork.  

Now, if I could just learn how to use the darned
things to actually tune a piano, I'd pass the last of
my RPT exams!  (as long as I don't have to tune in a
refrigerator or in August) 

Greg Graham
Brodheadsville, PA

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