What Do All Those Cogs Do?

What Do All Those Cogs Do?

By Gordon Fraser

08 Jul , 2020  

2 comment

What do all those cogs do? It’s a common question, especially with the Coniston, from customers who are seeing a mechanical movement for the first time.

We designed the Coniston to make the case-back as impressive as it could be, with a carefully chosen crystal for its magnification properties, and a construction that promotes the movement visually from the case. We think it worked out beautifully and the Coniston caseback is a design we’re very proud of. But, what do all those cogs do?


A mechanical movement is an incredible feat of engineering. To simplify things, as illustrated below, we’ve shown a linear version of everything that’s inside your standard 3-hander mechanical movement, like the Coniston, Haskell and Morar. The Lomond and other movements with “complications”, as they’re coined, have a few more moving parts to control these additional functions, but we'll be concentrating on the standard 3-hander movement for this piece. 


So let’s start with the power, the main source of what makes a watch tick. The power for a mechanical watch is stored inside what’s called the mainspring barrel. This is a capsule inside which rests a length of spring steel… Born in the USA! No, spring steel, which is called the mainspring. This is wound around a central core which, when coiled tightly, provides the potential energy to power your watch. But what happens when you release that potential energy and convert it to kinetic energy? Without anything to stop the mainspring barrel from spinning, it would whizz around uncoiling itself within a few seconds and come to a stop - not very useful for telling the time. So what the other wheels attached to the mainspring do is regulate the release of the mainspring’s energy, with a very strict set of parameters and calculations to allow it to keep time accurately as the energy is released.

So, as you see, the mainspring barrel has the 2nd wheel meshing with a pinion on its underside. The 2nd wheel in turn has the 3rd wheel meshing with it, and so on. Every wheel has a set ratio to allow each wheel to turn at a specific rate. The 2nd wheel has some other wheels attached above it, which allows us, through the use of a few more wheels and pinions, to attach the hour and minute hands centrally on the watch dial. As the mainspring unwinds, and with it the turning of each of these subsidiary wheels, we can see visually the hands rotating and thus know what the time is. Very nice! But, how do we make sure that these wheels are all turning at a rate that matches up with the internationally recognised standard of time!?


At the bottom of the illustration you’ll see the balance wheel - this is the most visually striking component of a watch movement - for when the watch is operating, it is bouncing back and forth very fast. It looks spectacular, and is the area of the movement that regulates the release of the mainspring’s energy. It does this using a palette fork and escape wheel, or together what’s called the “escapement”. The palette fork is swung back and forth by a small peg on the underside of the balance wheel, which in turn meshes either of the palette fork’s two jewels (the small pink blocks) with the escape wheel’s teeth. As the palette fork swings, the jewels hit one of the escape wheel’s teeth, moving each wheel in turn all the way back to the mainspring barrel. Each swing of the palette fork is incredibly small, but when you consider that the palette fork swings back and forth eight times a second, this tiny rotational movement soon adds up. This interface between palette fork jewels and the escape wheel teeth is what gives us the beautiful beating noise we so love about mechanical watches.

What do all those cogs do? A linear version of everything that’s inside your standard 3-hander mechanical movement, like the Coniston, Haskell and Morar.

What do all those cogs do? A linear version of everything that’s inside your standard 3-hander mechanical movement, like the Coniston, Haskell and Morar.

So, as you see, the mainspring barrel has the 2nd wheel meshing with a pinion on its underside. The 2nd wheel in turn has the 3rd wheel meshing with it, and so on. Every wheel has a set ratio to allow each wheel to turn at a specific rate. The 2nd wheel has some other wheels attached above it, which allows us, through the use of a few more wheels and pinions, to attach the hour and minute hands centrally on the watch dial. As the mainspring unwinds, and with it the turning of each of these subsidiary wheels, we can see visually the hands rotating and thus know what the time is. Very nice! But, how do we make sure that these wheels are all turning at a rate that matches up with the internationally recognised standard of time!?


At the bottom of the illustration you’ll see the balance wheel - this is the most visually striking component of a watch movement - for when the watch is operating, it is bouncing back and forth very fast. It looks spectacular, and is the area of the movement that regulates the release of the mainspring’s energy. It does this using a palette fork and escape wheel, or together what’s called the “escapement”. The palette fork is swung back and forth by a small peg on the underside of the balance wheel, which in turn meshes either of the palette fork’s two jewels (the small pink blocks) with the escape wheel’s teeth. As the palette fork swings, the jewels hit one of the escape wheel’s teeth, moving each wheel in turn all the way back to the mainspring barrel. Each swing of the palette fork is incredibly small, but when you consider that the palette fork swings back and forth eight times a second, this tiny rotational movement soon adds up. This interface between palette fork jewels and the escape wheel teeth is what gives us the beautiful beating noise we so love about mechanical watches.

The stunning Miyota 8N33 which powers our Coniston collection, which was selected not only for its reliability but also its delicate and eye-catching decorations.

The final part of the watch movement is the powering up of the mainspring barrel’s energy, and that is where you come in. By rotation of the crown, which in turn, through the keyless works, turns the mainspring barrel, you impart your energy into the watch allowing it to burst into life and show you the time of day. How absolutely wonderful is that?


If you would like to see this in action, and to enjoy my dulcet tones, please take a look at the video below - we recorded this a few months ago for another journal entry, but it's very relevant here too and illustrates how a movement functions. 



2 comments

Phillip Allenby-Carr

Very interesting and an easy(ish) insight into the internal workings of what is a lovely movement. Well put, so that, even an old and cantankerous, as I am, can get his head around it. My 70th is in a few months so I now khow what to request from the clan as my desired gift. Many thanks and keep up the good work. Regards.

Ken Morris

Special day today…meeting Daughter, son in law and grandson for the first time since February at the zoo and I’m going to give my ‘Speed Edition’ it’s first public outing !
Special watch for a Special day.
Keep up the good work guys.

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