English Clocks

Chapter 3

The Early Clockmakers

Craftsmen have constantly developed specialist tools and equipment. A master was paid to introduce his apprentices to the 'secrets' of the trade; innovations were generally closely guarded and few details of how early clocks and watches were made have survived. Horologists of the sixteenth and seventeenth centuries produced intricate and beautiful devices, seemingly with the aid of simple hand tools. Descriptions of the tools and equipment they developed are rare, so we need to treasure what few sources survive to shed even a little light on the work of these early artisans.

Clockmaking Tools

Files and Saws

The steel file was one of the most important tools in clockmaking, as it was in other crafts, such as making locks and weapons. Archaeologists have discovered bronze rasps from ancient Egypt dating from 1400bc, and from the seventh-century bc iron rasps are known to have been used by the Assyrians. Advances in steel making by the Middle Ages resulted in the development of hardened steel files, which were very similar to modern files. File blanks were originally forged, then the teeth were cut into the surface with a chisel. The file was then hardened by heating and quenching the steel.

File maker from the Housebook of Mendel, Nuremberg, 1554.

By the sixteenth century, file-making had reached a high degree of perfection and skilled craftsmen could produce small precision files with teeth numbered in the thousands. The illustration shows a complete workshop with a forge in the background. The file cutter uses an angled hammer to strike a chisel made from high-carbon steel - another hammer can be seen beside the anvil. The file blank, in its soft state, was held on a lead block with a strap, which was tensioned with a lever operated by the artisan's foot. When it was finished, the file was heated to a high temperature in the forge (this is shown in the drawing), then quenched in oil or water to harden the steel.

File cutter's hammer, English, nineteenth century.

File-making became concentrated in several areas, including Nuremberg in Germany, Florence in Italy and Sheffield in England. By the sixteenth century, the Lancashire town of Prescott had also become renowned for the quality of its files. The file cutter's hammer in the illustration is from the nineteenth century, but is identical to those in the sixteenth century; Sheffield makers used it to cut files in exactly the same way as the Nuremberg file maker.

Files from Encyclopédie de Diderot et d'Alembert, 1751.

The Encyclopédie de Diderot et d'Alembert of 1751 is one of the earliest sources of detailed drawings of many tools, including files and a piercing saw (Fig. 1). Tools such as these would still be familiar to artisans today.

Saw maker, sixteenth century.

Saws have an even longer history. Copper saws from as early as 3000bc are known to have been used in ancient Egypt to cut stone using quartz sand as an abrasive. Later, steel saws were made in a similar way to knives, with teeth filed into the edge before hardening. Fine saw blades were developed, probably by clockmakers in the sixteenth century for use in piercing saws to cut out complex shapes from sheet metal, such as crossing-out wheels - cutting out the metal between wheel spokes.

Drills

The earliest type of drill, the bow drill, was well known to the ancient Egyptians and in one form or another, has been used until the present day. The ancient Egyptian bow drill shows the operator spinning the drill bit with a bow, whilst his assistant supports the upper end of the drill with a wooden block.

Ancient Egyptian bow drill.

Drill types from the Encyclopédie de Diderot et d'Alembert.

Various types of hand-operated drills were in use by the sixteenth century. The illustration from the Encyclopédie de Diderot et d'Alembert (Figs 40-42) shows simple bow drills with pulleys attached. The drill bit was held in place with a block placed at A, the bit B was placed on the work and the bow string wound around the pulley. Fig. 43 shows a pump drill still popular with jewellers today; the flywheel B helps with stability.

Turning

Many parts of a clock or watch, such as wheels and pinions, were turned in the same way as furniture makers produced items such as chair legs. Turning was an essential skill to be mastered by an apprentice watch- or clockmaker. The illustration of an eighteenth-century watchmaker shows him using a bow in his left hand to spin a small part between centres. He uses a cutting tool called a graver in his right hand to remove metal.

Eighteenth-century watchmaker.

Egyptian two-man lathe.

This way of turning is simply a precision form of the earliest method of producing cylindrical objects developed over 3,000 years ago. Images have been discovered from ancient Egypt, such as the two-man lathe shown here from the tomb of a priest, c. 300bc. This shows one man spinning the object to be turned between centres with a rope, whilst the other holds the cutting tool.

Pole lathe, 1554.

Various types of lathes were familiar to the ancient Greeks and Romans, and by the Middle Ages pole lathes for turning wood and other materials would have been in regular use. A single operator using a foot treadle attached to a sprung pole could turn out items like chair legs with great rapidity.

Set of turns.

The use of turns to make and finish parts such as wheel arbors and pillars was practised well into the twentieth century - a skilled craftsman could produce work of an incredibly high standard with this simple tool.

CLockmakers in Medieval England

The makers of the early tower clocks for religious houses were probably itinerant craftsmen who set up on site, bringing with them specialist tools and materials. Most monasteries would have had a forge and blacksmiths on hand to provide facilities for fashioning the ironwork of the clock as it was constructed. The accounts of Salisbury Cathedral show that the Bishop of Salisbury, Ralph Erghum, in the mid-1380s invited three clockmakers from Delft, Johannes and William Vrieman and Johannes Lietuijt, to construct the Salisbury clock. In 1386, a house was provided for the clock keeper. The same team was sent to Wells by Bishop Erghum in 1388 to build another clock there; this clock is now in the London Science Museum. It is also believed that designs, or possibly complete clocks, were imported from the Low Countries in the late fifteenth century and a number of these clocks, known as the Dover Castle Group, have survived in the south of England. Many of these early clocks had elaborate astronomical dials.

Wells Cathedral astronomical clock dial.

The Late Fifteenth-Century Cotehele Clock

A peculiarly English style of tower clock appeared in the fifteenth century. Instead of the usual bird-cage construction, like the Salisbury Cathedral clock, the wheels were mounted in a vertical frame, with the escapement and foliot at the bottom. These appear to have been made mostly in the West Country and the Midlands.

Cotehele House, Cornwall.

Plan of Cotehele Chapel.

The chapel of this well-preserved medieval house was remodelled after 1485 when Sir Richard Edgcumbe, a supporter of the new King Henry VII, returned victorious from the Battle of Bosworth Field. At this time, a clock, which rang a bell on the hours, was installed in a cupboard-like alcove in the corner of the chapel.

This remarkable clock is, apart from the Salisbury and Wells Cathedral clocks, the earliest surviving in England and, unlike the other clocks, is in almost entirely original condition. Jonathan Betts (National Trust, Cotehele Journal, Vol. 8) notes that the well-preserved state of the mechanism indicates that it was not run for much more than a century. He ascribes this to the fact that the clock needed daily winding and regular oiling and maintenance to keep it working, so it was probably replaced by more reliable eight-day clocks from the seventeenth century onwards. The clock's location, out of sight behind a heavy door, explains why it appears to have been forgotten until it was rediscovered in 1952. Various restoration projects, notably by Thwaites & Reed in 1962, have restored the timepiece to working order.

Cotehele House clock, late fifteenth century.

The clock is shown here in its alcove, together with a diagram of the main working parts. All of the components are made from iron and a wooden framework supports the assembly. The two stone driving weights hang to the right of the movement and a rod goes upwards through the ceiling to ring the bell on the chapel roof. The going train with just a great wheel and escape wheel is below the striking work, with the foliot hanging suspended below the mechanism rather than the usual arrangement.

The construction of the mechanism is similar to that of the Salisbury Cathedral clock in many ways. The hoops of the wheels are mounted on two crossbars riveted in place. Before the teeth were marked out and filed, the arbor must have been fitted so that the wheel could have been spun in some kind of framework. This would have enabled the rim to be trued up by filing. Note that the wheel teeth are in the ancient triangular form.

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