Seiko Caliber 8R48 Mechanical Watch User Manual

Introduction to Seiko Caliber 8R48 Mechanical Watches

This document provides comprehensive instructions for the Seiko Caliber 8R48 mechanical watch, which features both automatic and manual winding capabilities. The watch is powered by a mainspring, and its accuracy is measured on a daily basis, differing from quartz watches.

The accuracy of mechanical watches can be influenced by various factors, including wearing conditions, ambient temperature, hand movement, and the tension of the mainspring. Exposure to strong magnetic fields can temporarily affect the watch's performance and may require demagnetization.

Table of Contents

• Characteristics of Mechanical Watches
• Names of Parts
• Usage
• How to Set Time and Date
• How to Use the Chronograph
• How to Read Chronograph Readings
• To Preserve the Quality of Your Watch
• Where to Store Your Watch
• Periodic Checks
• Warranty and Repair Tips
• Troubleshooting
• Accuracy of Mechanical Watches
• Specifications

Characteristics of Mechanical Watches

The watch is powered by a mainspring. If the watch stops, manually wind the mainspring by turning the crown approximately 20 times to start it.

While quartz watch accuracy is measured monthly or yearly, mechanical watch accuracy is indicated by a daily rate (slow or fast). The accuracy of mechanical watches during normal use varies based on usage conditions such as wearing time, ambient temperature, and mainspring tension.

Exposure to strong magnetic fields can temporarily cause watches to run faster or slower. If watch parts become magnetized due to strong magnetic fields, demagnetization is necessary. Please consult the store where the watch was purchased.

Names of Parts

The watch features:

• Hour hand
• Minute hand
• Chronograph second hand
• Chronograph minute sub-dial
• Chronograph hour sub-dial (typically up to 12 hours)
• Small second sub-dial
• Date window
• Crown (ЗАВОДНАЯ ГОЛОВКА)
• Chronograph Pushers:
  • A: Start/Stop Chronograph
  • B: Reset Chronograph

Crown Positions:

• a) Initial position: Manual winding, date setting, time setting.
• b) Pulled out to the first click: Date setting.
• c) Pulled out to the second click: Time setting.

The watch may be equipped with a screw-lock crown for enhanced water resistance. To use it, unscrew the crown by turning it counter-clockwise. After setting, screw the crown back in by turning it clockwise while gently pressing it.

[Note: The appearance of the dial may vary depending on the model.]

Usage

This watch is equipped with both automatic and manual winding functions.

• When worn on the wrist, the mainspring is automatically wound by the movement of your arm.
• If the watch has stopped, it is recommended to wind it manually by turning the crown.

How to Wind Manually

1. Slowly turn the crown clockwise (towards the 12 o'clock position).
2. Continue winding until the mainspring is fully wound. The small second hand will start moving.
3. Set the time and date before wearing the watch on your wrist.

[Note: Turning the crown counter-clockwise (towards the 6 o'clock position) does not wind the mainspring.]

There is no need to stop winding when the mainspring is fully wound; the crown can continue to turn without damaging the watch mechanism. If the watch is fully wound, it will run continuously for approximately 45 hours. Prolonged use of the chronograph may reduce this operating time. If the watch is not fully wound, its accuracy may fluctuate. To ensure accuracy, wear the watch for at least 10 hours a day. If using it as a desk clock, wind it manually every day at the same time. If the watch has stopped and the mainspring is not wound, manual winding may not start the watch instantly. This is because the initial torque from the mainspring is low. The small second hand will begin to move once the torque reaches a certain level after full winding. Gently rocking the watch can help start it faster.

How to Set Time and Date

Before setting the date and time, ensure the watch has sufficient power reserve.

Watches with a date function are designed so that the date changes every 24 hours, typically at midnight. If the AM/PM setting is incorrect, the date may change at 12 PM (noon).

1. Pull the crown out to the first click. (The small second hand will continue to move, maintaining time accuracy).
2. Turn the crown counter-clockwise until the date of the previous day appears. For example, if today is the 6th of the month, set the date to "5" by turning the crown counter-clockwise.
3. Pull the crown out to the second click when the small second hand is at the 12 o'clock position (it will stop). Turn the crown to move the hands until the date changes to the next day, indicating midnight. Set the time accordingly, ensuring it is AM or PM.
4. Return the crown to its initial position simultaneously with a time signal.

⚠️ PRECAUTION: Do not set the date between 8:00 PM (20:00) and 2:00 AM. Doing so may cause the date to change incorrectly, leading to a malfunction.

? TIP: The mechanical watch mechanism differs from a quartz watch mechanism. When setting the time, advance the minute hand slightly past the desired time, then turn it back to the exact minute mark.

Date Correction at Month End

Manual date correction is required at the end of months with fewer than 31 days.

Example: To set the date to the 1st of a month following a 30-day month, if the watch shows "31":

1. Pull the crown out to the first click.
2. Turn the crown to set the date to "1", then return the crown to its initial position.

How to Use the Chronograph

This watch is equipped with a chronograph function that can measure elapsed time up to 12 hours. The term "chronograph" refers to a watch with a function to measure elapsed time in addition to displaying the current time.

• Before using the chronograph, ensure the chronograph second hand is pointing at "0". Press pusher B (Reset) to correct its position if necessary.
• Ensure the mainspring is fully wound before operating the chronograph.

Chronograph Operation:

• Pusher A: Press to start the chronograph. Press again to stop it.
• Pusher B: Press to reset the chronograph hands to their zero positions.

The chronograph second hand completes a full revolution in 30 minutes. Pay attention to the position of the chronograph hour hand for accurate readings of the chronograph minute hand.

How to Read Chronograph Readings

The chronograph minute hand completes a full circle in 30 minutes. Observe the position of the chronograph hour hand for correct interpretation of the chronograph minute hand's reading.

Reading Minutes (0 to 29 minutes): When the chronograph minute hand is before the short marker (0.5-hour indicator), read the number of minutes indicated directly.

Reading Minutes (30 to 59 minutes): When the chronograph minute hand is after the short marker (0.5-hour indicator), add 30 minutes to the number of minutes indicated by the chronograph minute hand.

Reading Hours: The chronograph hour hand indicates the elapsed hours.

Example:

• Time displayed: 10 hours, 8 minutes, and 42 seconds.
• Chronograph time displayed: 6 hours, 20 minutes, and 10 seconds. (Minute hand is before the 0.5-hour marker, hour hand is at 6).

Example 2:

• Chronograph time displayed: 6 hours, 50 minutes, and 10 seconds. (Minute hand is after the 0.5-hour marker, hour hand is at 6. Add 30 minutes to the minute reading: 20 + 30 = 50).

[Note: Repeated starting and stopping of the chronograph can be done by pressing pusher A. The example readings show 6 hours 20 minutes 10 seconds and 6 hours 50 minutes 10 seconds.]

To Preserve the Quality of Your Watch

Care for Your Watch

The watch case and strap are in constant contact with your skin. Keep them clean to ensure longevity and prevent skin irritation.

• After removing the watch, wipe off any moisture, sweat, or dirt with a soft, dry cloth. This helps preserve the case, strap, and clasp.

Leather Strap

Gently wipe off moisture from the leather strap using a soft, dry cloth. Avoid rubbing the leather, as this may cause damage or color loss.

Metal Bracelet

To maintain the cleanliness of the bracelet, use a soft toothbrush dipped in clean water or mild soapy water. Be careful not to let water come into contact with the watch case.

⚠️ PRECAUTION: SKIN RASH AND ALLERGIC REACTION

• Adjust the strap so that there is a slight gap between it and your wrist to allow for ventilation.
• Some individuals may experience skin irritation or allergic reactions from prolonged contact with the watch.
• Possible causes for dermatitis include:
  • Allergic reactions to metals or leather materials.
  • Accumulated rust, dirt, or sweat on the watch or strap.
• If you experience any allergic symptoms or skin irritation, discontinue wearing the watch immediately and consult a doctor.

Caution When Wearing Your Watch

• Be cautious when holding infants or small children while wearing the watch, as they may get scratched or develop an allergic reaction from direct contact with the watch.
• Avoid impacts, drops, or scratches against hard surfaces, and refrain from strenuous sports activities that could cause temporary malfunctions in your watch.
• There is a risk of injury when wearing a watch on your wrist, especially if you fall or collide with other people or objects.

Where to Store Your Watch

• Avoid long-term storage of the watch at temperatures below 5°C (41°F) or above 35°C (95°F).
• Do not leave the watch in places exposed to strong magnetic fields (e.g., near televisions, loudspeakers, or magnetic bracelets) or sources of static electricity.
• Do not leave the watch in places with strong vibrations.
• Do not leave the watch in dusty environments.
• Do not expose the watch to chemicals or gases (e.g., organic solvents like benzine and thinner, nail polish remover, cosmetic sprays, detergents, glue, mercury, or iodine-based antiseptics).
• Avoid direct contact with hot water.

Periodic Checks

This watch is a precision instrument with many moving parts lubricated with special oil. If the lubrication becomes insufficient or parts wear out, the watch may show incorrect time or stop. Therefore, periodic checks are necessary.

Warranty and Repair Tips

For repairs or checks, please contact the store where the watch was purchased or a SEIKO SERVICE CENTER.

Please present the warranty certificate when seeking service within the warranty period. The warranty terms are detailed in the warranty certificate; please read it carefully and keep it.

Troubleshooting

[Note: For any other problems, please contact the store where the watch was purchased.]

Accuracy of Mechanical Watches

The accuracy of mechanical watches is indicated by daily rates, typically measured over a week.

The accuracy of mechanical watches may not align with the specified range due to variations caused by usage conditions, such as the duration the watch is worn on the wrist, hand movements, and the degree of mainspring winding.

The main components of mechanical watches are made of metals that expand or contract with temperature changes, affecting accuracy. Mechanical watches tend to run slower in high temperatures and faster in low temperatures.

To achieve optimal accuracy, it is crucial to regularly supply energy to the balance wheel, which controls the speed of the gear train. The driving force of the mainspring, which powers the mechanical watch, is not constant; it varies with the degree of winding. A lower mainspring tension results in less driving force.

Relatively consistent accuracy can be achieved by frequently wearing watches with automatic winding or by fully winding manual-winding watches daily at the same time.

Exposure to strong external magnetic fields can cause mechanical watches to temporarily run slower or faster. Watch parts may become magnetized depending on the strength of the magnetic field. In such cases, consult the store where the watch was purchased, as the watch may require servicing, including demagnetization.

Specifications

[Note: The accuracy indicated above is set at the factory. According to the characteristics of mechanical watches, actual accuracy may fall outside the indicated range depending on usage conditions such as wearing time, temperature, hand movement, mainspring tension, etc.]