How To Make A (Precise) Watch
Ok, let’s admit it. No one can show you how to make a watch in a single article.
But it is possible to provide the basics of what goes into every ‘wristlet’, as they were known at the turn of the 20th century.
Prior to the 13th century timekeeping was limited to very crude means. Sundials tracked a shadow produced by the motion of the sun.
Water clocks dripped at an approximate rate to fill a container. Marked candles burned down. Sand flowed through an hourglass. All smoothly changing devices.
But beginning in the 13th century, mechanisms were devised to chop the day into regular intervals. By the 16th century, those divisions became small enough and accurate enough for the minute and second to be defined and measured. By the 18th century, all the now-familiar components were in place.
Though pendulums were accurate, they couldn’t be used on ships or carried around. Inventors devised several ingenious methods to work around this limitation, but all perform essentially the same function: to oscillate at a predictable, steady rate (relatively) immune from outside forces.
In a mechanical watch, that oscillation is produced by the action of a set of gear wheels, ending in a mechanism called the escapement. That device causes those gear wheels – powered by a wound spring under tension (the mainspring) – to move a balance wheel in sections of a circle at a prescribed rate.
The gear wheels and escapement produce regular ticking, and move the hands of the watch at the correct rate.
But since wound springs eventually relax, they have to be re-tensioned periodically. Enter self-winding mechanisms.
Early methods arose in the 18th century, but the modern version was patented in 1923 and used in wristwatches as early as 1929. An off-balance weight rotates, winding the spring. A ratchet mechanism prevents it from rotating the wrong way.
Clever as mechanical watches are – and some are amazing, with over 1,700 precise moving parts – they are subject to limitations.
Temperature, shock and manufacturing imprecisions – not to mention the cost and complexity of assembly – kept mechanical watches from being the perfect solution.
Enter electric watches. Hamilton introduced the first in 1957 with the release of its ultra-stylish Ventura. Battery powered, it required no winding. Tuning fork controlled, its 360 cycles per second vibration provided a huge advance in precision.
But it was still largely mechanical. Many moving parts kept it from perfection.
Then came electronic watches. Hamilton produced the Pulsar, the world’s first digital watch. A micro-computer coupled to a quartz oscillator (vibrating at 32,768 Hz) with LEDs for display reduced the moving parts and error almost to zero.
Accuracy was to within a few seconds per month at first, and later improved further still.
In the 1990s came atomic-clock controlled watches. These don’t have atomic clocks inside the case. (Yet!). Instead, they have radio receivers that allow the watch to synchronize with an atomic clock maintained elsewhere. There’s one in Colorado and others around the world.
The ultimate in precision had arrived. Even if a quartz watch drifts off the ‘true’ time by a few seconds in a year, it can be put back on track (usually daily) by receiving that signal.
Now, you can never claim to be late because your watch ran slow.