Bolting bells to headstocks

[Bill Hibbert]

Matthew Higby:

> I was amazed that a small G&J bell that we rehung recently,
> changed in pitch when the bell was bolted to its stock (with
> fibre pad between). The prime rose around 10Hertz!

I have been told by bellfounders that such changes happen on the 
tuning machine when a bell is bolted down to the plate, but primarily 
to the hum. Apparently, if the bell is tuned while bolted down to the 
plate, the tuning goes off when you unbolt it, but is restored when 
the bell is bolted to the headstock.

Bob Perrin and Hervey Bagot did some research on this, the reference 
is Perrin, R., Swallowe, G. M., Charnley, T., Marshall C. "On the 
debossing, Annealing and Mounting of Bells" in Journal of Sound and 
Vibration (1999) 227 (2), pp 409-425.

Bill H