Қоңырлар құю және реттеу өнері

Practice of casting and tuning bells

Bellfounding is the casting and tuning of large bronze bells in a foundry for use such as in churches, clock towers and public buildings, either to signify the time or an event, or as a musical carillon or chime. Large bells are made by casting bell metal in moulds designed for their intended musical pitches. Further fine tuning is then performed using a lathe to shave metal from the bell to produce a distinctive bell tone by sounding the correct musical harmonics. Bellfounding in East Asia dates from about 2000 BCE Archaeological evidence of bellfounding appears in Neolithic China. The earliest metal bells, with one found in the Taosi site, and four in the Erlitou site, are dated to about 2000 BCE. By the 13th century BCE, bells weighing over were being cast in China. After 1000 CE, iron became the most commonly used metal for bells instead of bronze. The earliest dated iron bell was manufactured in 1079 , found in Hubei Province.

Portable bells came to Britain with the spread of Celtic Christianity, and most of those still remaining share an association with Scotland, Wales and Ireland. Bellfounding in Britain was due to monasticism which provided demand and expertise in the early medieval period. Large bells in England are mentioned by Bede as early as 670 CE and by the seventh or eighth century the use of bells had become incorporated into church services. Nearly 200 years later, in the tenth century is the first record of a complete peal of bells. The chronologies of the abbot Ingulf suggest that Thurcytel, the first Abbot of Crowland, presented the Abbey with a bell named Guthlac, after which his successor, Egelric the Elder cast an additional six bells—two large, two of medium size and two small—to complete a peal of seven. The same period saw other ecclesiastics involved in the founding of bells. St. Dunstan, "The Chief of Monks", was an expert worker in metals and known bell caster. Two bells were cast under his direction at Abingdon which also held two others cast by St. Ethelwold. Methods of moulding by lost wax casting were described by the thirteenth century Benedictine monk Walter de Odyngton of Evesham Abbey. Bellfounding as a commercial trade followed later. Independent craftsmen set up permanent foundries in towns, such as London, Gloucester, Salisbury, Bury St Edmunds, Norwich, and Colchester. Bell metal of these ratios has been used for more than 3,000 years and is known for its resonance and "attractive sound". Tin and copper are relatively soft metals that will deform on striking. By alloying, a harder and more rigid metal is created but also one with more elasticity than the use of one alone. This allows for a better resonance and causes the bell to "vibrate like a spring when struck", a necessary quality as the clapper may strike at speeds of up to 600 miles per hour. The forces holding the tin and copper together cause vibrations rather than cracks when the bell is struck which creates a resonant tone. This metal combination also results in a tough, long wearing material that is resistant to oxidation and subject only to an initial surface weathering. Verdigris forms a protective patina on the surface of the bell which coats it against further oxidation. The clapper or tongue is manufactured in a similar process as the bell. Special care is given to cast the clapper at the proper weight, as a clapper that is too light will not bring out the true tones of the bell and a heavy clapper might cause the bell to crack.