The watch precision has developed tremendously in time
Since the establishment of fixed hours, clockmakers have strived to render the watches as precise as they could, through different, ingenious devices.
We know from experience that tests conducted on the oldest surviving mechanical clock in the world, the faceless clock of the Cathedral of Salisbury, dating approximately to 1385, have discovered that the watch precision that this timepiece obtained was remarkable, within two minutes per day.
Such a performance – which was indeed very good for the time – would be replicated by watches only much later, and thanks to lots of development by figures like Galileo and Huygens.
Indeed, around 1650, another scientist called Robert Hooke theorized something that would be important for watchmaking: the theory of harmonic oscillations, which would be important for two key elements of the watch: the mainspring and the balance wheel. And as both of them use a spring in their operation, the smartest of my readers have understood about what we are talking about.
The application of Hooke’s Law
In short, a spring impart to a weight suspended on them a movement that is “harmonic” – it follows a constant sinusoidal oscillation path, if released.
In the ideal condition of no attrition, it would continue to oscillate like this forever.
But even if it doesn’t, if we continue to apply constant force to it making it move in such a way, the oscillation will continue regularly.
And this is the main principle we apply to watches.
The regulatory device of a watch works like this. That is, it is based around a harmonic oscillator of some kind.
The first harmonic oscillators used in watches were the balance springs. They are the tiny spiralling springs that lie on top of balance wheels and make them oscillate back and forth following a harmonic oscillation.
The increase in watch precision: electromechanical watches
In the quest for better precision, watchmakers discovered that a tuning fork emits a fixed vibration that is based on harmonic oscillation as well. The diapason was miniaturized and used as a regulating device in watches such as the Bulova Accutron.
The evolutions of electromechanical watches – which debuted in the 1960s – have brought us the quartz-based system, which works on a different system based on a similar concept.
In a quartz-based watch – the first one was the Seiko Astron, which was launched in 1970, we find an oscillator composed by a quartz crystal that is cut in a small tuning fork shape on a particular crystal plane.
Today, we are exploring other solutions to create a harmonic oscillator. The next frontier in this research will be the use of silicon elements. Several promising calibers have been manufactured, like the Zenith Defy. However, the industry is still using either mechanical-based regulating elements based on balance wheels or quartz-based systems (and their evolutions like the Seiko Kinetic and the Seiko Spring Drive.
How do you regulate these systems?
Obviously, when a watch comes out the factory it is not precise at all. It must be regulated to achieve a good precision. And watchmakers have developed ways to regulate the different movements so they perform at the best of their possibility.
The mechanical watches use an ingenious regulator placed obeve the balance wheel bridge (known as a balance wheel cock) – it is a regulator that can be turned to adjust the dimension of the hairspring. Diffenet dimensions would lend the balance wheel to beat slower or quicker.
While the regular watches had a lever, more precise ones have micrometric adjustments regulated by a screw. Some modern watches use different systems to regulate, such as counterweights placed on the balance wheel itself.
In a quartz-based watch, regulation is not possible. That is, it is already built in.
You can find much more about horology and its fascinating history in The Watch Manual. It is a thorough e-book that explains all the basics about watchmaking and its protagonists.