Clockmakers were pioneer builders of accurate mechanisms: the weight-driven clock was one of the first complex mechanisms that humans ever built. In 1381 Giovanni De Dondi built a clock that used some mechanisms like sun-and-planet gearing that were not to be used by mechanical engineers for another four centuries.
Many early clocks were used in churches. Being large, they were often built by skilled blacksmiths, using iron rather than brass. Rivets or wedges were used to hold them together and fixing holes would be punched, not drilled out. Few specialised tools were needed.
The ‘scaling down’ of clock mechanisms continued until the seventeenth century. Clockmakers' techniques, driven by wealthy customers’ demands for ever-smaller and more accurate timepieces, became far more advanced than for other technologies.
One of the simplest clockmaker’s tools was the ‘turns’ – a miniature lathe that could be held in a bench vice and turned by hand to precisely make tiny shafts and spindles for gear wheels.
More complicated were the wheel-cutting engines for producing the gear wheels that clocks required. Juanelo Torriano of Cremona completed a clock for Charles V of Spain in 1543 that needed 1800 gear wheels – a means of producing gear wheels accurately in large numbers was thus essential.
Fusée engines made the smaller spring-driven clock practicable, making the ‘fusée’ that, with its tapered shape, compensated for the progressive weakening of a coiled spring as it unwound. This helped ensure that the clock kept time.
Until the late eighteenth century there was no comparison between the clockmaker’s fine brass tools and the rough, mostly wooden, equipment of the millwright or engineer. It remained impossible to ‘scale up’ clockmakers' tools into industrial tools of equivalent accuracy. Clockmakers’ close guardianship of their techniques made it difficult for their ideas to be adopted elsewhere.
By 1775, with industry expanding, engineers were beginning to respond to the call for large, accurate machine tools: Britain stood on the brink of an engineering revolution.