What Is an Automatic Watch?

Tick-tock, tick-tock—every second matters, especially for the intricate machinery that lies within the sleek casing of an automatic watch. Digital watches and smart devices dominate the world today, but the artistry of traditional watchmaking continues to captivate enthusiasts and collectors alike.

But what makes an automatic watch tick? At the heart of every automatic watch is a remarkable movement, a delicate dance of gears, springs, and rotors working in harmony. With a flick of your wrist, you can keep your watch running indefinitely.

Understanding how an automatic watch works unveils a mechanical tapestry that’s often overlooked. Let's get into the inner workings of these exquisite timepieces.

What is an Automatic Watch?

Popularly known as a self-winding watch, an automatic watch is a mechanical watch that uses the natural motion of the wearer’s wrist to keep it running. Unlike quartz watches, which rely on batteries for power, automatic watches harness energy through a small, semicircular weight inside the movement called a rotor. As you move your wrist, the rotor swings, winding the mainspring, the energy source of the watch. This stored energy powers the watch without manual winding as long as it is regularly worn or stored in a watch winder.

What is the difference between Mechanical vs Automatic Watches?

All automatic watches are mechanical, but not all mechanical watches are automatic. The key difference lies in how they are wound and their reliance on the wearer for power.

Mechanical Watches

• Winding Method: Manually wound by turning the crown
• Power Source: Relies solely on a mainspring for energy
• User Interaction: Requires regular winding (daily or every few days) to keep running
• Components: Simpler design, typically with fewer parts than automatic watches
• Timekeeping: Generally, less convenient for daily wear due to the need for manual winding

Automatic Watches

• Winding Method: Self-winding through the movement of the wearer’s wrist
• Power Source: Uses a rotor that winds the mainspring as the watch is worn
• User Interaction: Can remain powered without manual winding if worn regularly
• Components: More complex design with additional parts, including a rotor
• Timekeeping: More convenient for daily wear, as they can be self-sustaining

How Do Automatic Watches Work? 

An automatic watch movement works by converting the energy from the wearer’s motion into power to keep the watch ticking. At its heart is the mainspring, a coiled metal spring that stores and releases energy to drive the watch's hands. 

1. Rotor and Mainspring Interaction: The rotor, a semi-circular weight attached to the movement, swings freely as the wearer moves their wrist. This motion causes the rotor to spin around its pivot, winding the mainspring incrementally with each swing. As the mainspring tightens, it stores energy in the form of potential energy, ready to release it steadily over time.
2. Power Transmission through Gears: The stored energy in the mainspring is transmitted through a series of gears, which help regulate and slow down the release of energy so the watch hands move in precise intervals. These gears include the gear train, escapement, and balance wheel, each with a unique function in controlling the flow of energy. The escapement and balance wheel work together to "tick" the seconds away in a regulated manner, ensuring the hands move consistently.
3. Balance Wheel and Escapement: The escapement releases energy from the mainspring in small, controlled increments. Each “tick” you hear from an automatic watch is the escapement allowing the gear train to move forward by a fraction, creating the iconic smooth sweeping motion. The balance wheel oscillates back and forth, further regulating the release of energy and ensuring accurate timekeeping.

When worn daily, the watch will stay wound due to your movements. 

How Does a Rotor Work?

The rotor’s function is what gives an automatic watch its self-winding capability. It provides a steady flow of energy as long as the watch is worn, eliminating the need for manual winding. Here’s how it works:

1. Swinging with Wrist: As the wearer moves their wrist, gravity causes the rotor to swing around its pivot, moving back and forth or in complete rotations. This motion doesn’t need to be vigorous; even light wrist movements are often enough to set the rotor in motion.
2. Winding the Mainspring: When the rotor moves, it engages a winding mechanism connected to the mainspring (the energy storage coil in a watch). As the rotor swings, it turns a series of small gears that gradually tighten the mainspring, storing potential energy that will be used to drive the watch’s movement. Because the mainspring winds incrementally with each rotor swing, continuous wrist motion means the watch can run without needing manual winding.
3. Automatic Winding Mechanism: Most modern automatic watches feature a unidirectional or bidirectional rotor winding system. In a unidirectional system, the rotor only winds the mainspring in one direction. In a bidirectional system, it can wind in both directions of rotor motion, improving efficiency. Some high-end watches use specialized mechanisms to prevent overwinding, automatically stopping the winding process once the mainspring is fully wound.

How Long Do Automatic Watches Last Without Winding?

Automatic watches typically last between 40 and 72 hours without winding; it all depends on the watch’s power reserve capacity. The power reserve is the amount of energy stored in the mainspring when fully wound, which determines how long the watch will run after being removed from the wrist.

• Standard Power Reserves: Most automatic watches are designed to last around 40 to 48 hours without additional winding. This means that if you wear the watch daily, it will stay wound. If you remove it on a Friday night, it will likely need rewinding by Sunday evening or Monday morning.
• Extended Power Reserves: Higher-end automatic watches or modern calibers often have extended power reserves, lasting up to 72 hours or even more. Some advanced models boast power reserves of 5 to 10 days, allowing them to run significantly longer without winding.

Factors That Affect Power Reserve

Several factors affect the power reserve of an automatic watch. Here are some of the main elements that impact how long an automatic watch movement can run on a full wind:

1. Mainspring Capacity: The length and flexibility of the mainspring directly impact the power reserve. Longer mainsprings can hold more energy, so watches with longer mainsprings generally offer extended power reserves. Luxury or high-performance watches, which sometimes have larger cases, can accommodate larger mainsprings for reserves of up to 5 days or more.
2. Efficiency of the Rotor Mechanism: The rotor is what converts wrist motion into energy A more efficient rotor design such as a bidirectional rotor can wind the watch more effectively than a unidirectional one. This results in a fuller wind even with minimal wrist movement. Higher efficiency leads to a more consistent power reserve.
3. Frequency of the Movement (Beat Rate): The rate at which the balance wheel oscillates, measured in vibrations per hour (vph), can influence energy consumption. Movements with a higher beat rate (e.g., 28,800 vph) are generally more accurate but consume energy faster. Watches with a lower beat rate (e.g., 18,000 vph) can run longer on the same amount of energy.
4. Condition and Maintenance of the Movement: Like any mechanical device, automatic watches require regular servicing. Worn or dried-out lubricants increase friction and resistance, causing the watch to draw more energy and reducing its effective power reserve. Regular maintenance ensures all parts are operating smoothly, preserving energy efficiency.
5. Complications and Added Features: Additional functions such as chronographs, GMTs, or perpetual calendars use extra gears and mechanisms that consume additional power. Watches with multiple complications tend to have shorter power reserves since more components draw from the same mainspring energy.
6. Temperature and Environmental Conditions: Extreme temperatures, especially very cold ones, can affect the flexibility of the mainspring and the viscosity of the lubricants, reducing the watch’s efficiency. When the watch is in ideal environmental conditions, its power reserve remains closer to its rated maximum.

Can You Overwind an Automatic Watch?

No, you cannot overwind an automatic watch. Automatic watches are designed with mechanisms that prevent overwinding even if they’re worn constantly or placed in a watch winder.

1. Built-In Slip Clutch: Inside the barrel that houses the mainspring, there is a slip clutch or bridle. Once the mainspring is fully wound, the slip clutch allows the spring to slip, preventing further tension from building. This prevents damaging the mainspring by ensuring that excess energy doesn’t keep winding it beyond its capacity.
2. Automatic Rotor System: The rotor, which powers the winding system, won’t continuously tighten the mainspring once it’s fully wound. Instead, it will keep moving but won’t increase tension in the mainspring. This makes automatic watches self-regulating, allowing them to remain fully wound without risking harm to the movement.
3. Watch Winders: If a watch is kept on a winder, the same slip-clutch mechanism protects the mainspring from overwinding. The winder mimics wrist motion, and the watch will wind only to the point of full capacity, with the clutch stopping additional winding.

For manual-wind mechanical watches, overwinding is possible due to the absence of a slip clutch, so users must take care when winding. With automatics, however, you’re safe from overwinding. As long as it’s regularly worn or on a watch winder, it will stay fully powered without risk of damage.

Can You Name Some Popular Brands and Models of Luxury Automatic Watches? 

Here’s a list of some popular luxury brands and their standout automatic models:

1. Rolex

• Submariner: A favorite due to its robust and classic design, the Submariner is a legendary diving watch and an enduring favorite.
• Daytona: This automatic chronograph is associated with motor racing and its high-performance movement.
• Datejust: A versatile and elegant model that suits both formal and casual wear, with Rolex’s signature date feature

2. Omega

• Seamaster Diver 300M: Known as James Bond’s watch of choice, it combines functionality and a sporty look with Omega’s Co-Axial escapement.
• Speedmaster Professional: The iconic “Moonwatch,” one of the most historic chronographs, is powered by Omega’s automatic movements in some variations.
• Constellation: This refined watch series is known for its precision with a Co-Axial automatic movement.

3. Patek Philippe

• Nautilus: With a distinct porthole-inspired design, the Nautilus has become one of the most sought-after luxury sports watches.
• Aquanaut: The Aquanaut is a more contemporary design with a rubber strap and a robust automatic movement.
• Calatrava: A symbol of classic elegance, the Calatrava’s minimalist design makes it an iconic dress watch.

4. Audemars Piguet

• Royal Oak: With its iconic octagonal bezel and “Tapisserie” dial, the Royal Oak is a groundbreaking luxury sports watch with an automatic movement.
• Royal Oak Offshore: A bold, larger version of the Royal Oak with a sportier look, this model is available in various chronograph and automatic versions.

5. Jaeger-LeCoultre

• Reverso: Featuring a unique reversible case, the Reverso is a classic Art Deco-inspired watch with some models featuring automatic movements.
• Master Ultra Thin: Elegant and sleek, this model features Jaeger-LeCoultre’s finely crafted automatic movements and appeals to fans of dress watches.
• Polaris: This versatile sports watch is inspired by the classic Memovox with modern automatic movements and a sporty aesthetic.

6. Tag Heuer

• Carrera: A racing-inspired chronograph with a sleek, automatic movement, this watch is cherished by motorsports fans.
• Monaco: With its square case and association with Steve McQueen, this timepiece is a distinctive, stylish chronograph with an automatic movement.
• Aquaracer: A robust diving watch with automatic movement, the Aquaracer is durable and waterproof.

7. IWC (International Watch Company)

• Portugieser Automatic: This timepiece has a nice blend of classic and modern, with a clean design and a powerful automatic movement.
• Pilot’s Watch: Inspired by aviation, it features a robust automatic movement and legible design.
• Ingenieur: Originally designed as an anti-magnetic watch, it has evolved into a versatile, sport-luxury timepiece.

When Should You Manually Wind Your Automatic Watch?

Manually winding an automatic watch is beneficial in a few situations:

1. After a period of inactivity: If an automatic watch hasn’t been worn for a few days, the power reserve will eventually deplete, and the watch will stop. Giving it a few manual winds (typically 20 to 40 turns) will bring it back to full power and start it running smoothly. 
2. For a Quick Power Boost: Even if the watch is running, it might be close to the end of its power reserve. A quick manual wind can give the mainspring a boost, ensuring that the watch doesn’t run out of energy prematurely. 
3. When Using a Watch with Complications: For watches with additional complications, keeping the mainspring fully wound is essential for maintaining accurate function. Manual winding ensures that all complications have the power they need to operate accurately, especially if you haven’t been as active or if the watch has been sitting in one place.
4. To Ensure Consistent Timekeeping: When an automatic watch is close to the end of its power reserve, it might lose a bit of accuracy. Manually winding it occasionally can help keep it fully wound, which makes timekeeping more accurate. This can be especially helpful if the watch has a high beat rate, which consumes power faster.

How to Wind an Automatic Watch Properly? 

To properly wind an automatic watch, follow these steps to ensure it’s done correctly and avoid unnecessary wear:

1. Take the watch off your wrist: Winding while on your wrist can put stress on the winding stem and crown as it requires you to hold the watch at an angle.

2. Unscrew the crown: Some automatic watches, especially water-resistant models, have a screw-down crown. Gently unscrew it counterclockwise until it pops out to the winding position. If your watch doesn’t have a screw-down crown, you can move to the next step.

3. Wind the watch clockwise:  Rotate the crown clockwise (away from you) in small, gentle turns. Typically, 20 to 40 turns should be enough to fully wind the mainspring. You don’t need to worry about overwinding an automatic watch, as it has a built-in mechanism to prevent this.

Unless it's specified by the manufacturer, avoid winding counterclockwise as it doesn’t add power and may not be beneficial for the movement.

4. Check for resistance: As you approach a full wind, you’ll start to feel slight resistance in the crown. Most automatics have a slipping clutch that prevents overwinding, so don’t worry if you feel it slipping—this is normal and protects the mainspring from damage.

5. Push or screw the crown back in: Once you’re done winding, push the crown back to its original position. For watches with a screw-down crown, gently press and turn the crown clockwise to secure it back in place, ensuring it’s properly sealed.

While it’s okay to manually wind an automatic watch now and then, avoid doing it excessively as frequent winding can cause unnecessary wear on the winding mechanism. A gentle wind when the watch has stopped or needs a power boost is generally all that’s needed to keep it performing well.

How Do You Maintain Your Automatic Watch?

Maintaining an automatic watch ensures its longevity, accuracy, and reliable performance. 

1. Regular Wear and Winding

• Wear it often: Wearing your automatic watch regularly keeps the movement and lubricants active. The natural motion of your wrist keeps the mainspring wound, helping the watch stay powered and running smoothly.
• Manually wind: If you don’t wear your watch daily, consider manually winding it every few days to maintain the power reserve and avoid stopping. Avoid winding excessively; 20 to 40 turns every few days should be enough.

2. Clean the Watch Regularly

• Wipe the case and bracelet: Use a soft, lint-free cloth to remove dirt, sweat, and oils that can accumulate on the case and bracelet. For metal bracelets, a soft toothbrush and mild soap can help remove grime. Avoid water for leather straps as it can degrade the material.
• Use a damp cloth: If the watch is water-resistant, you can gently clean it with a slightly damp cloth. Avoid submerging the watch in water unless the manufacturer specifies that it’s safe for swimming.

3. Keep It Away from Magnets

• Avoid strong magnetic fields: Magnets from electronics, speakers, and some household items can affect the movement’s accuracy by disrupting the balance wheel and escapement. Automatic watches are generally designed to resist everyday exposure but try to avoid strong sources of magnetism when possible.

4. Avoid Extreme Conditions

• Temperature: Avoid extreme heat or cold as this can affect the lubricants in the movement, causing them to thicken or thin out and potentially affecting timekeeping.
• Shocks and impacts: While most automatic watches are durable, they are still mechanical and can be damaged by strong shocks. Try to avoid activities like heavy sports or using machinery while wearing your watch.

5. Store It Safely

• Use a watch box: Store your automatic watch in a cool, dry place, ideally in a watch box or case to protect it from dust, light, and moisture.
• Watch winder: If you have a watch collection, a watch winder can keep your automatic watches running even when not in use. This helps prevent the lubricants from thickening and keeps the movement in good working condition.

6. Service Regularly

• Scheduled servicing: Automatic watches generally need servicing every 3 to 5 years. During servicing, a watchmaker will clean, lubricate, and adjust the movement, replacing any worn parts. This regular maintenance keeps the watch’s movement running smoothly and maintains accuracy.
• Inspect the seals: If your watch is water-resistant, have the seals and gaskets checked during service to maintain water resistance, especially if the watch is exposed to moisture or submerged regularly.

Conclusion

Automatic watches are timepieces that speak volumes of both artistry and precision engineering. The intricate workings of an automatic watch movement are themselves signatures of excellent craftsmanship that pays homage to the age-old tradition of watchmaking. With each gentle movement of the wrist, the rotor spins, harnessing energy that transforms everyday wrist motion into the rhythm of timekeeping.