The Whitechapel Bell Foundry, which was established in 1570, is the oldest manufacturing company in the UK, according to the Guinness Book of Records. It deals solely with the production of bells and associated fittings.
Bells from the foundry have been exported all over the world, bearing the company’s distinctive three-bell trademark, used by master founders at Whitechapel since 1583.
The company made the world’s most famous bell – the 13.5-ton Big Ben in 1858 – as well as the Liberty Bell in 1752 and the 9/11 bell in 2001.
Despite its many historical associations, the Whitechapel Bell Foundry is no museum. It is a working factory where traditional craftsmanship and modern technology combine.
PE, making up part of the IMechE Greater London South West Panel tour group, was shown around the foundry by the managing director Alan Hughes, whose family has been casting bells in east London since 1884.
The basic principles of casting bells have not changed. Molten metal is poured into a bell-shaped space within a mould. The process begins with the making of the cope, or outer mould. The moulding loam – a mixture of sand, clay, manure and goat hair – is applied by hand inside a bell-shaped iron flask and is smoothed to an exact profile using a strickle or moulding gauge.
The inner mould, known as the core, is built on a flat iron bedplate and is made of loam formed over a hollow brick foundation, and shaped using the same moulding gauge.
When it is almost finished, a craftsman impresses any inscription or decorative marks required on the bell.
The moulds are thoroughly dried in an oven, then later coated in graphite to give a smooth finish. The two halves of the mould are then firmly clamped together and closed down, leaving a space between them which corresponds to the precise shape, size and thickness of the bell to be cast.
Bell metal is an alloy consisting of 77% copper and 23% tin. The metal is melted in one of two furnaces. When it is ready the metal is run off into a ladle, skimmed to remove impurities, and then poured into the mould. When the metal has cooled, the cope is lifted off to separate the mould. The bell is removed, breaking away the loam, and it is leaned ready for testing, drilling and tuning.
A bell produces 40 discernible harmonic tones, which blend to give its tone. Modern bell-founders have realised that by bringing the five most prominent partial tones accurately into tune, the tone of a bell can be greatly improved. A bell is tuned by cutting metal from the inner surface on a lathe, and by measuring the frequencies. Restoration work often includes the retuning of old bells.
Once a bell has been tuned it is ready for hanging. Whitechapel offers a range of ringing fittings and bell frames. Traditional skills in fashioning wrought iron, timber, cast-iron and steel components allow the company to restore and repair existing installations.
The tours, on Saturdays, must be booked in advance.
For more details, see: www.whitechapelbellfoundry.co.uk
Five things to see
1. Bell founding: See and hear how bells are manufactured using the company’s two furnaces and drying oven. The process has changed little over the centuries.
2. Tuning area: The bells revolve around a movable cutting tool which is operated from above. The foundry’s restoration work frequently includes the retuning of old bells.
3. Historic bells: Walking around the foundry you can see many historic bells in various states of repair. Many are adorned with inscriptions about why they were made.
4. Hand bells: The foundry has made hand bells since at least the middle of the 18th century. Visitors can see a small tuning lathe of this date, the oldest machine in the foundry.
5. Mind your head: The premises are Grade II listed, so cannot be altered. Therefore, the front-age, the low ceilings and wonky wooden floors remain unchanged.