Tommy Black says: > I use C fork 523.3....always. I must be "right on" A440. You must be right on 440 if there is zero stretch in the piano (not on this planet). The tuning fork sets your "zero" point for stretch, and if that zero point is C, the A is going to be sharp. Not by much, though. Personally I think a bigger source of variation is the temperature of the tuning fork. I recently bought a C 523.25 fork, chunky aluminum type, and calibrated it using the Tunelab/NIST procedure that is so easy to do using Tunelab's instructions. I found that the difference between having the fork in the toolbox on a cold day, vs. having it under my waistband for 5 minutes, made a difference of just over 10 cents. There was easily a 50-60 degree F temperature difference between those two readings. My waistband tends to be consistent within a degree, whereas the temperature of the day, the car, the piano room all may vary a lot. This variation would cause far more deviation at A than would the degree of stretch. Spoken without measurements at hand, but someone must have measured the effect of temperature on a tuning fork. Ron? || ||| || ||| || ||| || ||| || ||| || ||| || ||| || ||| jason kanter * piano tuning * piano teaching bellevue, wa * 425 562 4127 * cell 425 831 1561 orcas island * 360 376 2799 || ||| || ||| || ||| || ||| || ||| || ||| || ||| || |||
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