Bellfounding

Bellfounding is the specialised craft of casting, metalworking, and tuning large bronze bells in a foundry for use in churches, clock towers, civic buildings, and musical installations such as carillons and chimes. The practice combines metallurgy, acoustics, and traditional craftsmanship to create instruments capable of producing powerful, resonant sound over long distances or precise musical tones within an organised scale. Bellfounding is one of the oldest continuous metalworking traditions in human history and has developed independently in several ancient civilisations.
Large bells are typically manufactured by casting bell metal into carefully designed moulds that determine the bell’s size, profile, and intended musical pitch. After casting, bells undergo a critical tuning process in which metal is shaved from the interior using a vertical lathe. This fine tuning aligns the bell’s partials with the correct harmonic series, producing the distinctive tonal quality associated with high-quality bells.

Definition and Uses

Bellfounding refers specifically to the production of large functional bells rather than small decorative or hand bells. These bells serve a variety of purposes, including:

• Signalling time from clock towers
• Marking religious services and ceremonies
• Announcing civic events, warnings, or celebrations
• Performing structured music in carillons and chime systems

The sound quality of a bell depends on a precise combination of alloy composition, shape, wall thickness, and tuning accuracy. Unlike most musical instruments, bells cannot be tuned by adjustment after manufacture without removing material, making precision in casting and finishing essential.

Origins and Early History

Bellfounding has played an important role throughout the history of ancient civilisations. East Asia produced some of the earliest known bells, many centuries before the European Iron Age. The earliest bells were made of pottery and later developed into cast metal instruments.
Archaeological evidence of bellfounding appears in Neolithic China, where early metal bells have been discovered at the Taosi and Erlitou sites, dating to around 2000 BCE. By the thirteenth century BCE, Chinese founders were casting bells weighing several tonnes, demonstrating advanced knowledge of bronze casting. These early Eastern bells are notable for their great size and ceremonial significance.
After around 1000 CE, iron increasingly replaced bronze for bellmaking in parts of China. The earliest dated iron bell, manufactured in 1079, was discovered in present-day Hubei Province. Despite this shift, bronze remained the preferred material for bells intended to produce refined musical tones.
In Europe, bellfounding developed later, becoming established during the fourth or fifth century CE, closely linked to the spread of Christianity. Bells quickly became integral to Christian worship, regulating daily monastic life and calling communities to prayer.

Development of Bellfounding in Britain

In Britain, early portable bells arrived with Celtic Christianity, and many surviving examples are associated with Scotland, Wales, and Ireland. The growth of Christian monasticism during the early Middle Ages created both the demand for bells and the skilled workforce required to produce them.
Historical sources indicate that large bells were in use in England by at least the seventh century CE. The scholar Bede mentions bells as early as 670 CE, and by the seventh or eighth century their use had become firmly embedded in church services. The tenth century provides the first record of a complete ring of bells, marking a major development in English bell culture.
Monastic chronicles record that Thurcytel, the first Abbot of Crowland, donated a bell named Guthlac to Crowland Abbey. His successor, Egelric the Elder, later cast six additional bells, creating a peal of seven. Other prominent ecclesiastics, including St Dunstan, Archbishop of Canterbury, were skilled metalworkers and active bellcasters. Bells were also cast under the direction of figures such as Æthelwold of Winchester.

Medieval and Commercial Bellfounding

By the later Middle Ages, bellfounding had developed into a commercial trade. Independent founders established permanent foundries in towns such as London, Gloucester, Salisbury, Norwich, Colchester, and Bury St Edmunds. Despite this, many founders remained itinerant, travelling from church to church to cast bells on site.
Archaeological excavations of British churchyards have revealed metallurgical furnaces and casting pits, confirming that bells were often cast within church grounds. Notable examples include Great Tom of Lincoln Cathedral, cast in the Minster yard in 1610, and the great bell of Canterbury Cathedral, cast in the cathedral precinct in 1762. In some cases, bells were cast inside the church building itself.
Early bells frequently suffered from poor tonal quality due to inconsistent alloy composition and limited understanding of acoustic principles. Over time, improvements in bell shape led to better sound. The waist of the bell became shorter, the soundbow more pronounced, and the overall profile refined to encourage a more harmonious distribution of overtones. Although tuning methods were still largely empirical, sets of bells arranged in diatonic scales became common in important parish churches and monasteries.
While bellfounding was predominantly undertaken by men, women also played a role, particularly through inheritance of family businesses. Figures such as Johanna Hill and Johanna Sturdy managed bellfounding enterprises and passed them on to the next generation.

The Low Countries and Scientific Bell Tuning

A major transformation in bellfounding occurred in the Low Countries during the seventeenth century. The brothers François and Pieter Hemony are regarded as the greatest carillon bell founders in the region’s history. Working in collaboration with the musician and acoustician Jacob van Eyck, they developed the carillon into a fully musical instrument.
In 1644, the Hemony brothers cast the first harmonically tuned carillon, applying scientific principles to bell shape and tuning. They were the first Western bellfounders to systematically align bell overtones according to harmonic theory, laying the foundation for modern bellfounding practice.

Materials and Bell Metal

Bells intended for functional sound are usually made from bell metal, a form of bronze alloy. The most widely accepted composition consists of approximately 80 per cent copper and 20 per cent tin, a ratio used for more than 3,000 years due to its excellent acoustic and mechanical properties.
Copper and tin are relatively soft when used individually, but when alloyed they form a harder and more elastic material. This elasticity allows the bell to vibrate efficiently when struck, producing sustained resonance rather than cracking. The alloy is also durable and resistant to corrosion, developing a protective verdigris patina that limits further oxidation.
Excessive tin content, however, makes bronze brittle. Alloys containing more than about 25 per cent tin have low melting points and are prone to cracking. This weakness famously contributed to the failure of the Tsar Bell in Moscow, which cracked in 1737 due to uneven cooling during a fire before it could ever be raised from its casting pit. Recasting old bells was common, as bell metal was extremely valuable, and remnants were often melted down for reuse.
Other materials have occasionally been used for bellmaking, including iron, brass, steel, and glass. Steel bells were produced in nineteenth-century England as a cheaper alternative to bronze, but they proved insufficiently durable and fell out of use by the 1870s. Glass bells, while capable of producing clear tones, were too brittle to withstand repeated striking.
A long-standing tradition holds that gold and silver were added to bell metal to improve tone, as wealthy donors sometimes threw coins into the furnace during casting. However, there is no reliable analytical evidence to support this belief.

Casting and Tuning Techniques

Traditional bellfounding involves constructing a mould composed of a core, a false bell, and an outer casing. Molten metal is poured into the cavity between the core and casing, forming the bell’s final shape. Once cooled, the mould is broken away and the bell cleaned and finished.
Precise tuning is then carried out using a lathe, removing small amounts of metal from specific internal zones. This process adjusts key partial tones, including the hum note, prime, tierce, quint, and nominal, bringing them into harmonic alignment.