Filing as described would lengthen the two tines slightly which should lower the frequency.

On 10/8/2021 8:13 PM, kn7sfz wrote:

On 10/8/2021 6:54 PM, Jim Haynes wrote:

On Fri, 8 Oct 2021, Nick England wrote:

I wonder why 425 Hz tuning forks would have been common? Musical A is 440
and A-flat is 415.3.
Maybe 2125/2975 came first and then 425 tuning forks? Hmmmmmmmmm.
Nick

I remember an article about building yourself a 425 Hz frequency standard,
since so few of us had access to frequency counters in the early RTTY days.  The musical standard then and now was A=440 Hz, but in an earlier
time it had been 435 Hz.  And there was someone who had a supply of 435
Hz tuning forks for sale.

So what we were supposed to do was carefully
use a rattail file at the crotch of the tuning fork and file away just
enough metal to bring it down to 425 Hz.

Would you not have to ADD weight to slow it down?

Just my 2 cents....😉

Richard de kn7sfz


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