[Watch repair and maintenance]

Q : What is an overhaul?

A. An overhaul (disassembly and cleaning) is a maintenance procedure in which the movement (internal machinery) of a mechanical or quartz watch is disassembled into its individual parts, cleaned, worn parts that are causing malfunctions are replaced, reassembled, lubricated, and finally the accuracy is adjusted.

Q. Why is an overhaul necessary?

A.No matter how expensive or excellent a watch you buy, it is better to have it overhauled in order to use it for a long time. Whether it is mechanical or quartz, there are many small parts, gears and shafts inside. Each of these parts has an important role, and even a small chipped part can cause problems with the running of the watch and even lead to breakdowns. To prevent this, overhauls are necessary.

QWhen is an overhaul required?

A. Overhauls are recommended every 3 to 5 years for mechanical watches, and every 5 to 10 years for quartz watches. The recommended timing is a guideline and varies depending on the manufacturer, model, and usage conditions. Regardless of how long you have used your watch, if you notice any problems such as the time losing or gaining speed, the crown being difficult to wind, or the watch's duration becoming shorter, do not hesitate to have it overhauled.

[Overhaul work flow]

The work flow for an overhaul may vary slightly depending on the function, type, and condition, but we will introduce the general flow.

① Disassembly
When overhauling a watch, the movement is removed. Once removed, the parts are disassembled one by one. At this time, the condition of the parts is inspected. If a malfunction occurs, we will identify the problem area and replace any damaged or deteriorated parts as necessary.

② Cleaning
The disassembled parts are then cleaned. We use a special cleaning machine and a special mixture of chemicals to carry out the cleaning work.

③ Cleaning and polishing the exterior
The exterior (case and bracelet) is cleaned using an ultrasonic cleaner to remove dirt, grime, rust, etc. After that, a process called polishing is carried out to give it a shine, and each part is polished to restore its new shine.

④ Assembly and lubrication
After cleaning, check under a microscope for any worn parts. After that, the movement is assembled while oiling the parts. The parts that need to be oiled vary depending on the model, and it is important not to use too much or too little oil. This is the most careful and precise part of an overhaul, and is a very nerve-wracking job.

⑤ Adjustment
We use precision measuring instruments to adjust the timing of mechanical watches.

⑥ Overhaul completed
Finally, the movement is placed into the case and the dial and hands are attached. We check the operation of the watch to make sure that the hands and date are turned properly, as well as conducting a waterproof test, a running test, and a winding test. We check the movement of the watch for a while, and if there are no abnormalities, the overhaul is complete.

[Movement parts ]

An overhaul (disassembly and cleaning) is the process of disassembling each part one by one . Do you know how many parts are in a mechanical watch? There are roughly 100 parts used in a mechanical watch. There are also many small parts inside the movement. Each one has a name and a role, and is essential for the watch to function properly.

Part Name

The parts of a watch are named according to their shape and function. These names come from a variety of sources, including English or French words that are simply written in katakana. This time, we will explain the names of parts based on an exploded diagram of the movement.

<Hand-wound watch>

Movement (front)

A watch movement has a front and a back. The side with the balance and gear train is called the "front." The back cover side of the watch itself is the "front" of the movement.

① Kohaze

The teeth of the ratchet wheel are blocked to prevent the mainspring from unwinding. Conversely, when the spring is wound, it slides over the teeth. The crackling sound that occurs when winding is the sound of this lock sliding over the teeth of the ratchet wheel.

② Click spring

The hook is designed to always be in contact with the teeth of the ratchet wheel. It is a part that rotates wheels such as ratchet wheels in one direction, preventing them from rewinding.

③ Barrel bridge

This is the bridge that supports the barrel. The winding mechanism is built into the bridge.

④ 2nd wheel ( center wheel )

In the basic gear train of a watch, the barrel is number 1, followed by number 2, number 3, number 4, and so on, in the order in which the gears mesh. This part is called the second wheel because it meshes after the barrel. It is a gear on the same axis as the minute hand, and amplifies the power from the barrel and transmits it to the third wheel. It is located in the center of the movement and rotates once per hour.

⑤ Third wheel

The next gear to mesh with the second wheel is called the third wheel. It is a speed increasing gear that transmits the power from the second wheel to the fourth wheel. It is one of the parts that make up the basic gear train, and is one of the parts that will most likely need to be replaced in an automatic watch that has been used for many years.

⑥ 4th car ( seconds wheel )

This is the gear between the third wheel and the escape wheel. It meshes with the escape wheel. It rotates once every 60 seconds. If the watch is equipped with a small second hand, it is on the same axis as the small second hand.

⑦ Escape wheel

This is the gear that meshes after the fourth wheel. In general, in a watch movement, this gear is called the escape wheel. Since it meshes with the pallet after the pivot, this gear has a special shape. It transmits the power transmitted through the train wheel to the pallet, and also transmits the speed regulation to the train wheel.

⑧ Incense barrel / first wheel

It houses the mainspring and is the part that powers the watch movement. It is often called the barrel, an abbreviation of wheel. It is a box-shaped gear that houses the mainspring. Its role is to prevent the spring from breaking due to over-winding and damaging other parts. Generally, a "rotating barrel" is used, in which the barrel itself rotates, and in that case the "barrel gear" acts as the "first gear" and transmits power to the second pinion.

⑨ Main plate

This is the base on which all other parts are assembled. The movement is completed when the main body and each part are assembled onto this plate.

⑩ Crown wheel

It transmits the force that winds the winding stem to the ratchet wheel. It is called a crown wheel in contrast to a ratchet wheel. It is one of the parts of the winding mechanism, and its role is to transmit the power transmitted from the crown to the winding wheel and counterwheel to the ratchet wheel.

⑪ Ratchet wheel

Since it winds the barrel axon of the mainspring, its hole is square to prevent slipping. It is called a ratchet wheel after the shape of the hole. It is a gear necessary when winding the mainspring, and the hole of the central gear is square. This allows the gear and shaft to mesh tightly, and it can withstand the strong force used to wind the mainspring.

⑫ Round hole seat

This part is placed between the pinion wheel and the axis of the main plate. It helps the pinion wheel slide and prevents wear on the main plate.

⑬ Earthquake-resistant device (receiving side)

It acts as the sliding part of the balance wheel and protects the balance wheel axis and balance shaft from shocks. There are various types of this type depending on the manufacturer, such as Incabloc and Kifshock.

⑭ Regulator

This hand is used to adjust the speed of the watch by adjusting the distance the hairspring moves (effective length).

⑮ Bearded uke

This fixes the balance spring's stud and adjusts the balance spring's orientation (center of reciprocating motion).

⑯ Gear train bridge /2nd bridge

It mainly mounts the gear train onto the main plate. It is the bridge that holds the gear train in place.

⑰ Balance bridge

This is the bridge in which the balance is installed. The regulator, balance stud, and shock-proof device are also installed in the balance cock. This bridge supports the balance shaft and holds the balance unit.

⑱ Temp ( balance with hairspring )

It includes the balance wheel and hairspring. It moves back and forth to keep the watch moving at a constant speed. It is part of the escapement, which is made up of the balance wheel, balance shaft, and rotor seat. It converts the power transmitted through the wheel train, escape wheel, and anchor into a regular system together with the spring at the center of the balance.

⑲ Ankle support

This is a support for assembling the ankle.

⑳ Earthquake-resistant device (base plate side)

This is an earthquake-resistant device on the base plate side. Its role is the same as that of the earthquake-resistant device on the receiving side.

22. Pallet fork

It transmits power from the escape wheel to the balance, and transmits uniform motion from the balance to the escape wheel. It is a part that composes the escapement between the balance and escape wheel. It has two pawls, and is so named because it is shaped like a ship's anchor. These two pawls advance the escape wheel alternately, adjusting the vibration of the balance. An escapement mechanism that has this anchor is called an anchor escapement, and the plate that supports the axis of the anchor is called an anchor bridge. It is an essential part for regular wheel train motion.

Movement (back)

22. 　Setting lever jumper

The parts around the back are pressed down and assembled into the main plate. This is a part around the winding stem, and is the spring that creates the clicking sensation when the winding stem is pulled.

22. Yoke

When the crown is pulled, the mandarin duck pushes the tsuzumi wheel, engaging it with the small iron wheel, helping to adjust the time. The mandarin duck engages with the tsuzumi wheel, and the bolt is pushed by the mandarin duck pulled by the crown, engaging the tsuzumi wheel and the small iron wheel. The signal is then transmitted from the small iron wheel to the middle wheel, which turns the tsutsu wheel via the day wheel, allowing the time to be adjusted.

㉔ Latch spring

When the crown is in its normal position, press the latch to keep the timing wheel and the locking wheel engaged.

㉕ Minute wheel

It connects the Tsutsukana and the Tsutsu wheel. In order to make the Tsutsu wheel rotate once per hour, the speed of the Tsutsukana is reduced from one rotation per minute. This gear is directly linked to the display parts such as the hour and minute hands.

27. 　Setting wheel

This gear acts as an intermediate wheel to transmit rotational force from the Tsuzumi wheel to the Hinoura wheel.

22. 　Small railway intermediate car ( intermediate setting wheel )

This gear meshes with the small iron wheel when the crown is pulled out one notch, and transmits rotation to the date indicator fast-forward wheel.

27. 　Mandarin duck ( setting lever )

It engages with the winding core, and when the crown is pulled, the mandarin duck is also pulled, and at the same time the bolt is pushed out. This allows the wheel to move away from the clockwork wheel and move to the small iron wheel, allowing the time to be set. This is a part necessary for setting the time.

22 　Winding stem

This is the axis that is connected to the crown and is used to wind the mainspring and set the time.

21 　Crazy car

This gear is connected to the crown through the winding core and transmits the force that winds the mainspring from the winding core to the crown wheel.

22 　Clutch wheel

This is a drum-shaped gear that switches between turning the winding core and winding the mainspring.

22 　Tutu wheel / hour wheel

This is a gear that rotates once every 12 o'clock and has the hour hand attached to its tip.

22. 　Tsutsukana / Minute wheel

This is the part to which the minute hand is attached.

Automatic Watches

Automatic winding components

① Rotor

Instead of winding the shoes by hand, the movement of your arm moves a rotor that winds the mainspring, a weight that rotates in both directions to store energy.

② Transmission wheel

This gear meshes with the rotor pinion to transmit the winding torque to the automatic winding mechanism.

③ Automatic winding transmission

The automatic winding mechanism is built into the top and bottom and is combined with a rotor via a pairing.

④ Intermediate reduction wheel and pinion

This gear is placed between the transmission wheel and the reduction wheel. The rotation from the transmission wheel is also reduced here.

⑤ Reduction wheel and pinion

This gear reduces the rotational force from the rotor and increases the torque in order to turn the mainspring.

⑥ Transmission intermediate car

This is another gear that receives rotational force from the transmission wheel. It transmits force in the opposite direction to the reduction wheel.

⑦ Switching wheel

Transmission wheelThis gear reverses the rotation received from the intermediate wheel and transmits it to the reduction wheel.

⑧ Automatic winding transmission wheel (lower side)

Together with the upper bridge, this bridge supports the gears of the automatic winding mechanism.

⑨ Train wheel setting lever

This is the lever that stops the watch mechanism when the crown is pulled out.

⑩ Base plate

This is the basic watch mechanism assembled. The automatic winding mechanism will be installed on top of it.

<Quartz watch>

Clocks that run on batteries are called quartz clocks because they use a quartz crystal oscillator as the time source.

① Battery

Quartz watches mainly use button batteries. The type of battery used varies depending on the watch, and if the type is different, the watch may not function properly. Most quartz batteries need to be replaced every two to three years. If a dead battery is left, it can leak or over-discharge, affecting the movement around the battery.

② Quartz crystal unit

This is the heart of a quartz watch. The reference signal generated by the quartz crystal controls the movement of the second and minute hands. The quartz crystal gives quartz watches higher accuracy than mechanical watches.

③ Microchip ( IC circuit)

The battery-powered quartz crystal vibrates, and the IC circuit converts it into an electrical signal once per second. The electrical signal is then transmitted to a step motor, which moves the gears.

④ Step motor

This is a motor that rotates once per second according to an electrical signal. The number of vibrations per second is fixed. When the IC has counted the number of vibrations for one second, it applies voltage to the step motor to advance the second hand by one step.

[For overhauls, come to Comptoine!]

Do you have any of these concerns about your watch?

"My watch has stopped working." "I'm worried about it losing or gaining time." "The crystal has broken." "Water has gotten into the case." "The crown has come off." "I'm worried about scratches on the case or bracelet." "The crown is heavy." "I can't change the date properly." "I'd like to have my watch overhauled, but I don't know where to go." "I'd like to have the watch inspected first." "There's no watch shop nearby." "Do you repair any brand?"

At Comptoine, we can solve all of your watch problems.

Any brand is acceptable. We also handle vintage and antique watches. Our highly trained craftsmen will repair your watch with a customer-first policy. Please contact us even if you have been turned down for a repair at another store. Estimates are free so that you can rest assured.

Please check here for the overhaul price list.

We offer watch repair services at the Yoyogi watch and jewelry boutique "CONTÉVANOU." We look forward to hearing from you.