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Does high frequency provide greater shock resistance?
The greater stability of a higher frequency movement is often attributed to a sportier, shock-resistant quality in a watch. This is because the higher frequency movement will do a somewhat better job of dealing with the distorting effect of gravity pulling on the balance from different angles or when it endures a sudden shock.
Think of two cars driving over the same pothole, one travels at 30 kilometers an hour and the other at 80 kilometers an hour. Both cars experience a shock, however the car traveling slower experiences the disturbance for a longer period of time.
In a similar way, the higher the frequency of a movement the more quickly it can recover from shock.
While the precision of a higher frequency movement is less affected by shock than a lower frequency movement, there are three important caveats. First, as with accuracy, an increase in balance frequency is only one of several tools that a watchmaker can employ in an attempt to create a shock-resistant watch.
The Incabloc system, which is found on many modern mechanical movements, the pare-chute system (invented by Abraham-Louis Breguet in 1790), and other proprietary shock absorbers placed on the balance bridge or wider movement will most significantly contribute to the shock resistant qualities of the watch.
Secondly, the primary goal for shock resistance is to avoid damage to parts. When a momentary shock disrupts a handful of vibrations it will not put a perceivable dent in your watch’s accuracy, but a snapped balance staff certainly will!
Thirdly, another method of resisting shock in the movement is to increase the moment of inertia. As we have just discussed, this can be achieved by increasing the weight and/or size of the balance wheel, which consequently lowers the frequency of the movement.
There does not exist any meaningful objective data using a large enough sample size on the actual timekeeping impact of a shock or a series of shocks inflicted upon a range of movements with frequencies between 2.5 and 5 Hz. However, we are certainly talking about imperceivable differences not worth losing sleep over; differences that better serve the marketing of a watch than the wearing of one.
This is why you still see manufactures such as Audemars Piguet using the 3 Hz Caliber 3120 in its Royal Oak Offshore Diver watches. Yes, it beats at 3 Hz, but it has a double balance bridge, shock absorber on the pivot stone, and its variable inertia blocks allow the watchmaker to adjust the watch to a high level of accuracy. So dive away!
For those occasionally needing to handle a pneumatic drill or ride a bike down a mountain, it’s best to keep a cheap quartz watch in your collection.
Does higher frequency mean a more accurate chronograph?
This is where things get really interesting and more objectively clear.
When it comes to recording lapses of time, if your goal is to record at the most granular interval possible, then high frequency absolutely does mean a more accurate chronograph. Consider two one-meter rulers: one has 100 cm markings, the other has 1,000 mm markings.
They both measure a meter with equal accuracy and they both measure to the nearest centimeter with equal accuracy, but only one is capable of measuring to the nearest millimeter. This logic also applies to the movement frequency: any mechanical chronograph can be geared to measure to the nearest hour, minute, and second. But when it comes to measuring the space between seconds, increased balance frequency is king.
A 4 Hz balance with Swiss lever escapement vibrates eight times per second. With each vibration, the escape wheel unlocks so that it can deliver an impulse to the balance. In doing so, it graduates one tooth further along its rotation. This means that in any given second, the 4 Hz-tuned escape wheel allows the gear train to progress by 8 increments. Similarly, a 5 Hz movement creates ten vibrations per second, allowing the gear train to progress by ten increments each second.
A foudroyante second hand, which indicates fractions of a second, can therefore display one-eighth of a second or one-tenth of a second with a 4 and 5 Hz movement respectively. The foudroyante hand displaying one-sixth of a second on the Jaeger-LeCoultre Duomètre à Chronographe, for example, indicates that its Caliber 380 has a frequency of 3 Hz.
Likewise, the Zenith El Primero Striking Tenth with its special chronograph hand displaying one-tenth of a second is clearly powered by the famous El Primero 5 Hz frequency.
Alternatively, a watchmaker can use regular chronograph gearing and simply add the applicable graduations in between the second markers for the chronograph hand. This works for lower frequencies too. Take the A. Lange & Söhne Datograph Up/Down, which has five intermediate markers between every second marker allowing the wearer to take a reading to the nearest fifth of a second – not bad for 2.5 Hz.
It might surprise you, but there exist some beautiful high-end chronographs on the market that use similar graduations but with 3 or 4 Hz movements; consequently the frequency does not map to the markings, which should instead be providing readings to one-sixth or one-eighth of a second.
The higher you go in terms of frequency, the greater the granularity, but also the more challenges that need to be overcome. Take power, for instance, which in many cases is in higher demand with higher frequency balances.
This is why you will often see independent balance wheels and escapements set aside for the running of a high-precision chronograph, while a more traditional set is used for the timekeeping gear train as evidenced by the TAG Heuer Mikro range of chronographs and the Breguet Reference 7077 (see Breguet La Tradition 7077 Independent Chronograph: Twins Or Not?).
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