The bell casting is then taken to the tuning shop where it is placed, mouth upwards, on a large vertical lathe which has a revolving turntable. The bell is struck with special mallets to vibrate the metal in the areas which produce the main harmonics. After assessment by the Bell Master, the Bell Tuner removes small chips of metal uniformly from the inside of the bell until the vibrations of each of the main harmonics reach the correct frequency.

Bells in the Making
John Taylor Bellfounders