Thanks John, My room temp is 20 degrees. I wondered about the specifics of temperature- certainly the manufacturers could not mean that the fork itself is 20 degrees and not the room? As steel will always be colder than its surroundings- cannot recall the exact science behind the difference in heat conductors. I guess the underarm trick simply adjusts the fork enough to be accurate? I wonder about the fork- I will take mine into a master tech- to do any filing- but this will likely be necessary. Zoe -----Original Message----- From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of John Ross Sent: December 28, 2009 12:12 PM To: pianotech at ptg.org Subject: Re: [pianotech] beginner's calibration question If you are sure that the fork is off, remembering that temperature has an effect on it, some people put it under their arm for a predetermined time before measuring. As a matter of interest, just how accurate should a fork be? +/- what? The fork frequency can be changed with a file. I think I remember correctly, I am sure someone will correct me if I am wrong. :-) Take some off the tips to raise the frequency, and some off the inner part of the leg to raise the frequency. John Ross Windsor, Nova Scotia. ----- Original Message ----- From: "Zoe Sandell" <yiddishtangofever at shaw.ca> To: <pianotech at ptg.org> Sent: Monday, December 28, 2009 4:01 PM Subject: [pianotech] beginner's calibration question Hello, I have just completed calibrating my tuning device with NIST and the Tunelab demo-. When I call back the C5 500Hz marks as in tune- ie squares stay still- but my tuning fork reads flat at A440 How then do I accurately tune the temperament octave to the tuning fork- knowing this discrepancy? Get a new/better tuning fork? Thanks Zoe
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