TUNING OF BELLS

Lake Wakatip Mail, Issue 4156, 1 May 1934, Page 2

TUNING OF BELLS

NUMBER OF TONES Most people are not aware of tlie fact that a bell .yields five distinct tones audible to the ordinary ear, and seven, ten, or even thirteen tones recognised by the trained ear. When next you hear a bell ringing try to locate the exact note on .your piano. It is a difficult tiling to do at first, because one hears not a single note, but a chord of five notes. The most prominent is the strike-note, as it is called. Likewise one hears the hum-note, which is an octave lower, the octave above the strike note, the minor third, and the major fifth. These five notes must be in absolutely perfect pitch if a bell is to be in proper tune with itself. In fine tuning, even more harmonics must be brought into correct tune. Bellfounders have known this for a long time, but the difficult task was to do it properly. Small bells are especially hard to tune, and that is why the average small chapel bell or school bell sounds like a fire wagon approaching. The harmonics are out of tune. Tuning is accomplished by placing the bell mouth upwards in a vertical lathe, and with delicately-adjusted but powerful cutting machinery skimming off thin shavings of metal on the inside of the bell. Just where and how much to take off is the big problem. The old-timers worked by crawling inside the bell and chiselling away, each stroke of the hammer causing the bell to ring. Sometimes this went on for days and weeks.