THE TUNING OF BELLS

Evening Post, Volume CXVII, Issue 65, 17 March 1934, Page 19

THE TUNING OF BELLS

MOST people are not aware of the 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, tryr to locate the exact note on your piano. It is a difficult thing 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 tne^ 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 m 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. Bell-founders have known.this for a long time, but the difficult task was to db 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. TKfe harmonics -aw"out ot tune, -Tuning is accomplished by placing the bell mouth upwards m a vertical lathe, and witii'delicately-adjusted but poweriul cutting machinery skimming off thin shavings of metal on'the inside of the bell. Just where and how much to take off is the bi» problem. Ihe old-timers worked by crawling inside the bell and chiselling awdy,, each stroke of the hammer causing the bell to ring., sometimes this went on for days and weeks.