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Everything You Need To Know - Regulators Part V

Everything You Need To Know Regulators Part V

Go from rookie to expert with our essential geek guide to the heart of a watch mechanism

You’ve made it this far in our little online course on horological regulators, and you’ll be pleased to know that the rest of the course is much easier than what we covered before. It’s the dessert in a particularly complex multi-course dinner. And just like dessert, you’re allowed to take your time with it, and you should even have a little break, just to digest the heavy bits of the meal that came before. And when I say digest, I mean it’s probably a good idea to read through the previous chapters once again, to make sure you’ve managed to get everything well internalised.

Recap time! Do we know what a regulating organ is? Yes! Do we know that it consists of an oscillator and escapement? Yes! Do we know that a wristwatch oscillator is, in the vast majority of cases, a hairspring and balance wheel? Do we know how the balance works? Do we know what the escapement does and how it’s done? Yes, yes and yes! Positive affirmation is important, you guys.

So how does all this relate to what we see on the dial of a watch? The hands turning around and pointing to numbers and telling us how much time has passed in a day; how does that result from the balance swinging back and forth and the pallet fork being bashed left and right?


Escape wheel © Montres Breguet

It all comes down to the escape wheel. Now, we haven’t stated this explicitly, but if you’ve properly digested the previous lessons, you’ll know that each oscillation of the balance requires two impulses from the pallet fork, one in each direction. A 4Hz balance oscillates four times per second and those four oscillations require eight impulses. Each impulse is basically energy escaping from the mainspring, and visually we can see when this happens, because the pallet fork pivots and the escape wheel rotates a small bit. 

This means that in a 4Hz balance, the escape wheel takes eight small rotational steps per second. In fact, every single wheel from mainspring barrel to escape wheel makes the same eight tiny steps per second. It’s just easier to see in the escape wheel, because it has a higher rotational speed than the others and therefore it rotates over a larger angle per step than the other wheels. 

Can you tell where this is going? The escape wheel is connected to another wheel that makes the seconds hand go round, moving with the same number of steps per second. In a 4Hz watch, the seconds hand takes eight tiny steps to move from one second marker to another. In a 3Hz watch, the seconds hand takes six steps to move from one second marker to another. 

You can see why people use the seconds hand as a quick litmus test of whether a watch has a mechanical or quartz movement. In a quartz watch, the seconds indication (if there is one) moves in distinct jumps from one second to the next. In a mechanical watch, the seconds indication (if there is one) moves in this multi-step motion from one second to the next. (That is, unless they’re fitted with a dead seconds mechanism, but we don’t have to talk about that right now.)

In terms of timing precision, what does this tell us? It means that the smallest unit of time measurable by any mechanical watch is an inverse function of its frequency. A watch that beats at a higher frequency is capable of measuring smaller fractions of time. A 3Hz watch has a seconds hand that moves six times a second, right? So each time it moves, that’s one-sixth of a second. A 4Hz watch has a seconds hand that moves eight times a second and therefore it can indicate eighths of a second. 


Chronomaster Sport © Zenith

The Zenith El Primero movement beats at 5Hz, which is why it’s able to accurately indicate tenths of a second. This is emphasised in their chronograph watches with their Striking 10th chronograph seconds display — a seconds hand that goes around the dial once every 10 seconds instead of once per minute. You can see the chronograph seconds hand making a total of 100 jumps in each rotation. 

If you’re stressing out about internalising all this stuff, not to mention the previous chapters, don’t worry. You don’t have to. You don’t even have to want to. At the very least though, you can learn how to identify the regulating organ in any watch movement just by looking at it. It’s pretty easy. Sometimes it’s visible from the dial-side of the watch; mostly you can see it through the transparent caseback. It’s almost always the fastest moving thing in a watch movement (assuming the watch is actually running), and the back-and-forth rotation of the balance is a dead giveaway. 


Incabloc anti-shock device © Incabloc

Because of how important and delicate the balance is — remember, it’s the thing that allows your watch to actually keep time — it’s protected by a shock-proofing system, which is visually very distinctive. This is another tip-off that will let you identify a regulating organ, especially if your watch has more than one of them. That’s right. A very small handful of watches, such as the TAG Heuer Mikro series of chronographs, the Zenith Defy 21 and the Vacheron Constantin Traditionnelle Twin Beat Perpetual Calendar, actually have two regulating organs. 


Traditionnelle Twin Beat Perpetual Calendar © Vacheron Constantin

With the TAG Heuer and Zenith watches, one of those regulating organs functions as the “default” one, with the second regulating organ only being activated when the chronograph is started. In the Vacheron Constantin, you can switch the watch between using either regulating organ, so you’ll only see one of them in action at any given moment. This is why I said the regulating organ is almost always the fastest moving thing in a watch movement. Not always, but almost. Because sometimes you can get a regulating organ that’s not moving at all, even if the watch is running. 

Excited to find out more about the most important part of a watch movement? I’m going to assume you said yes, because the next part of the syllabus is about hairsprings. To be absolutely precise, the next part of the syllabus is more than you ever wanted to know about hairsprings. You’re gonna love it.


This article series is dedicated to Dr Rebecca Struthers, who kindly offered her expert comments on the text. Dr Struthers is the co-founder of Struthers Watchmakers and the first British watchmaker to receive a PhD in horology. 

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