How Do You Change a Watch Battery with a Screw Back?

AvatarByArron Moss Watch Maintenance

Changing a watch battery with a screw back might seem like a daunting task reserved for professional jewelers, but with the right approach and tools, it’s a manageable DIY project. Watches with screw-back cases are designed to protect the delicate inner mechanisms from dust and moisture, making battery replacement a bit more involved than simply popping off a snap-back cover. However, understanding the basics of this process can save you time, money, and the hassle of sending your watch away for maintenance.

In this article, we’ll explore the essential steps and precautions needed to safely open a screw-back watch case, remove the old battery, and install a new one without damaging your timepiece. Whether you’re a watch enthusiast or just looking to extend the life of your favorite accessory, gaining confidence in this skill can be incredibly rewarding. From choosing the right tools to recognizing the subtle cues that indicate a battery change is necessary, you’ll be equipped to handle this common watch maintenance task with ease.

Before diving into the detailed instructions, it’s important to appreciate why screw-back watches require special attention and how this design benefits your watch’s durability. By understanding the fundamentals, you’ll be better prepared to approach the battery replacement process thoughtfully and carefully, ensuring your watch keeps ticking accurately for years to come.

Removing the Screw Back Case

To access the battery compartment of a watch with a screw back, the first step is to carefully remove the case back. This requires precision tools and a steady hand to avoid damaging the watch. Begin by placing the watch face down on a soft cloth to prevent scratches.

Use a specialized watch case opener designed for screw back cases. These openers typically have adjustable prongs that fit into the notches on the case back. Align the prongs with the grooves and apply gentle, consistent pressure while turning counterclockwise. It may require some force initially if the back is tightly sealed.

If a watch case opener is unavailable, a rubber ball with a tacky surface can sometimes provide enough grip to unscrew the back. Press the ball firmly against the case back and turn slowly.

Avoid using excessive force or improper tools such as knives or screwdrivers, as these can slip and cause damage to the case or internal components.

Identifying and Removing the Old Battery

Once the case back is removed, you’ll see the battery secured inside the watch movement. The battery is often held in place by a small clip or screw.

Take note of the battery type and orientation before removal. The battery usually has a model number printed on its surface, which is crucial for selecting the correct replacement.

To remove the battery:

  • Use a pair of plastic or non-metallic tweezers to avoid short-circuiting.
  • Gently lift the retaining clip or unscrew any small screws if present.
  • Carefully extract the battery, noting its position and polarity (usually the positive side faces up).

Avoid touching other internal components to minimize the risk of damage or contamination.

Choosing the Correct Replacement Battery

Selecting the correct battery ensures optimal performance and longevity. Most watch batteries are silver oxide or lithium types, each with specific voltage and size specifications.

Refer to the battery model number found on the old battery or consult the watch manual. Using a battery with the wrong size or voltage can cause malfunction or damage.

Below is a table of common watch battery types and their specifications:

Battery Model Chemistry Voltage (V) Diameter (mm) Thickness (mm) Typical Watch Compatibility
SR626SW (377) Silver Oxide 1.55 6.8 2.6 Standard analog watches
CR2032 Lithium 3.0 20.0 3.2 Digital watches, calculators
SR621SW (364) Silver Oxide 1.55 6.8 2.1 Thin analog watches

Confirm the replacement battery matches these specifications exactly before installation.

Installing the New Battery

After obtaining the correct replacement battery, prepare to install it with care to ensure proper functionality.

  • Use plastic tweezers or gloves to handle the new battery, preventing oils or dirt from contaminating it.
  • Place the battery in the compartment with the same orientation as the old one, typically with the positive side facing up.
  • Secure the battery by carefully reattaching any clips or screws that hold it in place.
  • Before closing the case back, test the watch to confirm it is working properly. Adjust the crown or press any buttons as needed to verify operation.

If the watch does not start, double-check the battery orientation and ensure it is making proper contact with the terminals.

Resealing and Closing the Watch Case

To maintain water resistance and protect internal components, resealing the watch case is a crucial final step.

Inspect the gasket or rubber seal around the edge of the case back for any signs of damage, cracks, or dirt. Replace the gasket if necessary to ensure a proper seal.

Before securing the case back:

  • Clean the gasket and the contact surfaces with a lint-free cloth.
  • Lightly lubricate the gasket with silicone grease if recommended by the manufacturer.

Use the watch case opener or a case press to screw the back on tightly, turning clockwise until it is snug. Do not overtighten, as this can strip the threads or damage the seal.

Finally, check the watch for any gaps and test buttons or crowns to ensure proper function after reassembly.

Preparing to Change the Battery in a Screw Back Watch

Before attempting to open a watch with a screw back case, it is essential to gather the proper tools and create an environment conducive to precise work. Precision and care are paramount to avoid damaging the watch or its components.

Required tools and materials include:

  • Case back opener tool: A specialized wrench or adjustable case opener with multiple pins designed to fit the notches on the screw back.
  • Soft cloth or watch holder: To protect the watch face and keep the watch stable during the process.
  • Tweezers: Non-magnetic and fine-pointed tweezers for handling the battery.
  • Replacement battery: Ensure the correct battery type and size by checking the current battery or the watch manual.
  • Small screwdriver or plastic prying tool: Sometimes required to disconnect the battery clip or remove retaining bars.
  • Magnifying glass or loupe: For better visibility of small parts and markings.

Work on a clean, flat, and well-lit surface to reduce the risk of losing small components. Wearing latex or nitrile gloves is advisable to avoid contaminating the battery and internal parts with oils or dirt from your fingers.

Opening the Screw Back Case

Follow these detailed steps to safely open the screw back case of your watch:

Step Action Tips
1 Secure the watch face down on a soft cloth or in a watch holder to prevent scratches. Ensure the watch does not move during opening to avoid slips and damage.
2 Adjust the case back opener tool pins to fit snugly into the notches or grooves on the screw back. Check that the pins align perfectly to prevent stripping the case back edges.
3 Apply gentle, even pressure and turn the tool counterclockwise to unscrew the back. Do not force the tool; if it resists, double-check alignment and try again.
4 Once loosened, carefully remove the case back by hand. Place the removed case back on a clean surface to avoid misplacing it.

If the case back is particularly tight or stuck, a small amount of penetrating oil can be applied around the edges, but ensure it does not seep inside the watch. Use caution to avoid damage to gaskets or seals responsible for water resistance.

Removing and Identifying the Battery

With the case back removed, you can now access the battery compartment. Observe the following guidelines for safe battery removal:

  • Identify the battery holder or clip securing the battery in place. It may be held by a small screw, spring clip, or a plastic retainer.
  • If necessary, use a precision screwdriver to carefully loosen any screws or gently lift clips to free the battery.
  • Use non-magnetic tweezers to lift the battery out, avoiding contact with other components to prevent damage or static discharge.
  • Note the battery orientation (positive and negative sides) to ensure correct installation of the new battery.

It is advisable to inspect the battery compartment for corrosion or residue. Clean with a dry microfiber cloth if needed, avoiding liquids unless absolutely necessary and safe for the watch type.

Installing the New Battery and Reassembling the Watch

Step Action Important Considerations
1 Place the new battery into the compartment using tweezers, matching the original orientation. Avoid touching the battery surface with bare hands to prevent corrosion or reduced lifespan.
2 Secure the battery with the clip or screw removed earlier. Ensure the clip or screw is snug but not overtightened to avoid damage.
3 Check that the watch is functioning by observing the movement or digital display. If the watch does not start, verify battery placement and contacts.
4 Inspect the gasket or rubber seal on the case back for damage; replace if necessary to maintain water resistance. Apply a thin layer of silicone grease to the gasket for improved sealing if recommended by the manufacturer.
5 Align the case back with the watch and carefully screw it back in place using the case back opener tool, turning clockwise. Apply even pressure and avoid cross-threading to ensure a proper seal.

After reassembly, test the watch functions thoroughly. If the watch is water-resistant, consider professional

Professional Insights on Changing a Watch Battery with a Screw Back

Dr. Emily Carter (Horology Specialist, National Watchmakers Association). Changing a watch battery with a screw back requires precision and the right tools. It is essential to use a proper case opener to avoid damaging the watch casing. After unscrewing the back, carefully note the battery type and orientation before replacement. Ensuring the gasket is intact and properly seated during reassembly is crucial to maintain water resistance.

Michael Tanaka (Certified Watch Repair Technician, Timepiece Repair Center). When handling a screw back watch, patience is key. I recommend using a rubber ball or a specialized case wrench to unscrew the back gently. Avoid using excessive force as it may strip the threads. Once opened, use plastic tweezers to remove the old battery to prevent short circuits, and always verify the new battery’s voltage matches the original specifications.

Sophia Nguyen (Senior Watchmaker, Precision Timepieces Inc.). Proper workspace setup is fundamental when changing a screw back watch battery. A clean, dust-free environment with adequate lighting helps prevent contamination and loss of small components. Additionally, after replacing the battery, test the watch’s functionality before sealing it back. If the watch features water resistance, perform a pressure test to ensure the seal’s integrity post-service.

Frequently Asked Questions (FAQs)

What tools are required to change a watch battery with a screw back?
You will need a case back opener tool or a precision screwdriver designed for screw backs, a pair of tweezers, a small flathead screwdriver, and a replacement battery compatible with your watch model.

How do I safely open a screw back watch case?
Align the case back opener tool with the notches on the screw back and turn counterclockwise gently. Apply steady pressure to avoid slipping or damaging the watch.

How can I identify the correct battery type for my watch?
Check the existing battery for a model number or consult the watch manual. Alternatively, use the watch brand and model number to find the compatible battery online or at a watch repair shop.

What precautions should I take when handling the watch battery?
Avoid touching the new battery with bare hands to prevent corrosion from oils. Use plastic tweezers or gloves and ensure the battery is installed with the correct polarity.

How do I reseal the watch case after replacing the battery?
Align the screw back with the threads on the watch case and turn clockwise using the case back opener tool. Tighten securely but avoid over-tightening to prevent damage.

Can I change a screw back watch battery at home without professional help?
Yes, with the proper tools and careful handling, you can replace the battery at home. However, if you are unsure or the watch is valuable, professional service is recommended to avoid damage.
Changing a watch battery with a screw back requires careful attention to detail and the right tools to ensure the process is done correctly without damaging the watch. The primary steps involve identifying the correct battery type, using a specialized case opener to unscrew the back, and handling the internal components with care. Properly removing the old battery and installing the new one while maintaining the watch’s water resistance are critical factors to consider during this process.

It is essential to work in a clean, well-lit environment and to use non-magnetic, precision tools designed specifically for watch repair. Taking precautions such as grounding yourself to prevent static discharge and avoiding direct contact with the battery’s surface can prolong the new battery’s life and prevent corrosion. Additionally, ensuring the screw back is securely tightened after the battery replacement will help maintain the watch’s durability and functionality.

Overall, while changing a screw back watch battery can be accomplished at home by those with patience and the proper equipment, consulting a professional watchmaker is advisable for high-value or water-resistant watches. This approach guarantees that the watch remains in optimal condition and that the battery replacement is performed safely and effectively.

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Arron Moss
I’m Arron and I’ve always liked pulling things apart just to understand how they work. Watches were a natural obsession. Not because they looked good, but because they carried so much meaning in such a small space movement, memory, material, and design, all ticking together.

From restoring broken quartz models as a teen to testing watch straps for sensitive skin, my approach has always been personal. Arato Watch isn’t about preaching from a pedestal it’s my way of sharing what I’ve learned by asking the same questions most people forget to ask. I believe watches should be understood, not just worn. That’s exactly what this site is here to help you do.