Watch movement simulator

What you are looking at

A mechanical watch is a spring trying to unwind and a mechanism that refuses to let it. The mainspring sits coiled in the barrel, the big toothed drum. It turns the centre wheel, which turns the third wheel, which turns the fourth wheel, and each pair trades force for speed. By the time the power reaches the small steel escape wheel there is very little force left, but it would still spin all the stored energy away in a few seconds if nothing stopped it.

What stops it is the pallet fork, the little anchor-shaped lever with two red stones. One stone or the other is always in the path of a tooth. The fork only moves when the balance wheel swings past and knocks it across, and the balance swings at a rate set by its hairspring and nothing else. So the wheels can only advance when the balance says so. That is the whole idea of a watch, and it is easier to see than to read about. Choose the Escapement view and 1/100 speed.

One tick, in five steps

Press Next beat a few times and follow the text under the picture. This is what happens, in order.

1. Locked. A tooth of the escape wheel is resting against the side of a pallet stone. Every wheel in the watch is standing still. The balance is far out on its swing and touches nothing.
2. Unlocking. The balance comes back through the middle. The ruby pin under it enters the notch in the fork and starts pushing the fork sideways, which slides the stone out from under the tooth. The face of the stone is angled so that this pushes the wheel backwards by a fraction of a degree first. That angle is what holds the fork safely in place between ticks.
3. Impulse. The corner of the tooth reaches the slanted end of the stone. Now the wheel is doing the pushing. The tooth slides down the slope, drives the fork across, and the fork hands that push to the balance through the same ruby pin. This small shove, eight times a second, is the only thing that keeps the balance swinging.
4. Drop. The tooth falls off the end of the stone. For about a degree and a half the escape wheel is free.
5. Lock. Another tooth lands on the second stone, which the fork has just swung into its path. Steel hits ruby. That is the tick you hear, and it is the moment the seconds hand moves.

Then the balance swings out the other way, comes back, and the same thing happens on the other stone. Two beats let one tooth through.

Why the seconds hand gives a watch away

The seconds hand sits on the fourth wheel, so it moves exactly when the escapement lets it. It never glides. It stops and starts, several times a second, and how many times depends on how fast the balance beats. Switch the beat rate above and watch the chart next to the dial: the staircase gets finer or coarser.

This is why the seconds hand is the first thing people look at on a suspect watch. A Rolex Submariner has never been made with a quartz movement, so one that ticks once a second is not a Submariner, and you can stop there. The cheapest fakes still fail this way.

The next tier of copies uses an inexpensive automatic movement that beats at 21,600 inside a watch whose genuine calibre beats at 28,800. The hand sweeps, but in six steps a second where there should be eight. Side by side with the real thing it looks slightly grainy. On its own, most people can't tell.

How to count it yourself

Film the dial with your phone in slow motion. At 240 frames a second the steps are easy to count: play it back, pick a one-second stretch between two markers and count how many times the hand moves. Then check that number against what the genuine calibre for that reference should do. You can also hold the watch to your ear. Eight ticks a second is a quick, even purr, and six is audibly slower. Turn the sound on above and switch between the two to hear the difference.

What this can and can't tell you about a fake

It can rule a watch out. It can't rule one in. That distinction matters more than anything else on this page.

• A sweeping hand proves very little. The better counterfeits use clone movements built to the same layout and the same 28,800 beat rate as the calibre they imitate. The hand moves exactly as it should.
• A ticking hand isn't always wrong. Rolex made the Oysterquartz into the early 2000s. Omega, Cartier, TAG Heuer, Breitling and Grand Seiko all sell genuine quartz watches today. Check what the specific reference is supposed to have inside it.
• Plenty of genuine watches beat slower than 28,800. A real Speedmaster Moonwatch runs at 21,600. So does a real Seiko. Slower is not cheaper, it is a design choice.
• Some genuine hands really do glide. Grand Seiko's Spring Drive has no escapement at all and its hand moves without steps. Bulova's Precisionist quartz moves sixteen times a second.

So treat the seconds hand as one check among several, and the easiest one to do without opening the watch. The dial printing, the engravings, the weight and the movement itself all say more. If you have photos of a watch and want a second opinion on those details, the scanner on our front page goes through them and tells you what it can and can't see. For anything expensive, an in-person inspection by a watchmaker who opens the case is still the only real answer.

The quartz side

Switch to Quartz and almost everything you just learned disappears. There is no mainspring, no escapement and no balance. A battery makes a sliver of quartz, cut in the shape of a tuning fork, vibrate 32,768 times a second. That number is two multiplied by itself fifteen times, which is not a coincidence: a chip halves the frequency fifteen times and ends up with exactly one pulse a second.

Each pulse goes through a coil and magnetises an iron frame for a few thousandths of a second. In a hole in that frame sits a magnet about a millimetre across. It flips half a turn, three small wheels gear that down, and the seconds hand jumps one mark. Then nothing moves for the rest of the second. Slow it down and you can see the magnet overshoot and wobble before it settles, which is the tiny shiver you sometimes notice in a quartz seconds hand.

A quartz watch could move its hand eight times a second. It steps once because that uses the least energy, and because a balance wheel is the only reason a mechanical watch needs to move in small steps in the first place.

What is real here and what is simplified

We would rather tell you than have a watchmaker point it out.

• Real: the escapement geometry. The escape wheel is driven forward constantly and is stopped only by contact between its teeth and the two pallet stones. The locking, the small recoil, the impulse and the drop are worked out from the shapes thousands of times per simulated second. Nothing about the tick is drawn by hand.
• Real: the numbers. Tooth counts, gear ratios, beat rates, steps per second and step sizes are exact, and the fourth wheel turns once a minute at every beat rate.
• Simplified: the balance. It follows an ideal swing at the chosen frequency. A real balance is nudged slightly off its rhythm by every impulse, which is what watchmakers spend their careers correcting.
• Simplified: the layout. The model uses a 20-tooth escape wheel at every beat rate and changes one gear pair to get the speed right. Real calibres vary. The parts are also drawn larger and further apart than they would be, and the bridges that hold everything in place are left out so you can see.
• Simplified: the sound. It is generated from the simulated impacts, not recorded from a watch.

Questions people ask

Does a smooth, sweeping seconds hand mean a watch is real?

No. It only tells you the movement is mechanical, and counterfeiters have used mechanical movements for decades. The better copies run at the correct beat rate too. The hand can rule a watch out, when a model that only exists as a mechanical watch ticks once a second or steps more coarsely than it should. It can't confirm anything.

How many times per second does a Rolex seconds hand move?

Eight, on almost every modern Rolex, because the calibres beat at 28,800 vibrations per hour. Each step is three quarters of a degree. The Land-Dweller beats at 36,000 and moves ten times a second. The discontinued Oysterquartz is a genuine Rolex that ticks once a second.

Why does a mechanical watch tick?

Each tick is a small collision. The balance knocks the fork aside, a tooth slides off one stone, the wheel jumps forward and the next tooth lands on the other stone. That landing is the loud part. You can hear all three sounds separately if you turn the sound on and slow the simulator down.

What is the difference between 21,600 and 28,800 vph?

It is the number of times the balance swings in an hour. At 21,600 the seconds hand moves six times a second, one degree at a time. At 28,800 it moves eight times a second, three quarters of a degree at a time. The faster rate shrugs off knocks a little better. The slower one is gentler on the parts and on the power reserve.

Why does a quartz watch tick only once a second?

To make the battery last. The crystal already keeps time thousands of times more finely than the hand shows. Moving the hand more often would cost energy and gain nothing.

What do the timing machine controls do?

The mainspring slider changes how far the balance swings, which is what watchmakers call amplitude. The regulator makes the watch run fast or slow, and you will see the line of dots tilt. Moving the impulse jewel off centre makes the tick and the tock uneven, which splits the trace into two lines. A real timing machine reads all three from sound alone.

Keep reading

• How a mechanical watch actually works, the long version in words
• Beat rate converter, for turning vph into hertz and ticks per second
• How to read a timegrapher
• Automatic vs quartz, if you are choosing between them
• The superclone arms race, on why the easy tells keep disappearing
• Rolex Submariner authentication guide