Tuning Fork temperature

[Greg Graham]

Matthew, 

You asked why tuning fork temperature is important, and how to calibrate the fork.  

See my message in the archives demonstrating a simple experiment with fork temperature:

https://www.moypiano.com/ptg/pianotech.php/2005-August/177804.html

I did learn how to use the fork and passed my RPT exam.  As it happened, my fork was exactly 440 that day.  The examiners commented on never having seen a fork "stop the lights" like that.  It was more luck than skill to be that precise, but I did calibrate my fork at a PTG regional conference workshop.

Regarding calibration:  Filing the ends of the fork raises the pitch, and filing at the notch lowers pitch.  Go slow, take small bites, and take the same amount off each side.  Use a good Electronic Tuning Device (not a guitar tuner), and allow the fork to return to your desired "calibration temperature" after each filing.  

I prefer to place the fork on the piano plate while getting everything else ready to go.  I always keep my tools with me, so they don't freeze or bake in the car.  The fork and plate will be at room temperature, which may be above or below ideal, thus my comment above about hitting 440 being luck.  

Others prefer to calibrate at armpit body temperature because it is more consistent.  Be aware that the fork temperature will change (slowly) as you use it.  I inserted the handle of mine in a short piece of plastic tubing to insulate it from my hand and/or teeth.  If you use body temperature, the fork will cool in the air as you hold it, so keep tucking it under your arm.  

Just find out what works, then do it that way EVERY TIME.  

Good luck.