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

AvatarByArmando Lewellen Usage Guides

Changing a watch battery with a screw back might seem like a task reserved for professionals, but with the right approach and tools, it’s a manageable DIY project that can save you time and money. Whether your favorite timepiece has stopped ticking or is running slow, replacing the battery yourself can bring it back to life without the hassle of visiting a jeweler. Understanding the basics of how screw-back cases work is the first step toward confidently tackling this maintenance task.

Watches with screw-back cases are designed to provide a secure seal, protecting the delicate internal components from dust and moisture. While this design offers durability, it also means that opening the back requires a bit more care and precision compared to snap-on cases. Learning the proper techniques and using the correct tools ensures you won’t damage your watch during the process. This article will guide you through the essential considerations and general overview of changing a battery in a screw-back watch, setting the stage for a successful and rewarding repair experience.

Tools Required for Opening a Screw Back Watch Case

To effectively open a screw back watch case, specific tools designed for precision and safety are essential. Using the right tools helps prevent damage to the watch case, the movement inside, and the battery compartment.

  • Case Back Opener: A specialized wrench designed to fit the notches on the screw back case. These come in adjustable models or with interchangeable tips to fit various sizes.
  • Case Holder: A tool that secures the watch firmly during the opening process to prevent slipping and damage.
  • Tweezers: Non-metallic or anti-magnetic tweezers are recommended to handle the battery carefully without causing short circuits.
  • Small Flathead Screwdriver: Useful for prying the battery clip or small components gently.
  • Soft Cloth or Pad: To protect the watch face and back from scratches while working.
  • Magnifying Glass: Assists in viewing small components clearly.

Using these tools correctly ensures a smooth battery replacement procedure and maintains the integrity of the watch.

Steps to Remove the Screw Back Case

Opening a screw back watch requires a methodical approach to avoid damage. Follow these steps carefully:

  1. Secure the Watch: Place the watch in the case holder or on a soft, stable surface. This prevents accidental slips and protects the crystal and case.
  2. Align the Case Back Opener: Adjust the case back opener to fit perfectly into the notches or grooves on the screw back. The fit should be snug to avoid slipping.
  3. Apply Controlled Pressure: Turn the case back opener counterclockwise with steady, even pressure. Avoid sudden or excessive force, which can strip the notches or damage the case.
  4. Remove the Case Back: Once loosened, carefully lift the case back away from the watch body. Some screw backs may have a gasket for water resistance; handle this gently to avoid damage.
  5. Inspect the Interior: Before proceeding, take note of the battery type and orientation for proper replacement.

Identifying and Removing the Battery

Once the watch case is open, the battery is typically visible but may be held in place by a retaining clip or cover.

  • Identify the Battery Type: Usually a small, round, silver oxide or lithium coin cell. Common sizes include SR626SW, CR2032, and others.
  • Note Battery Orientation: Observe the positive (+) and negative (-) sides to install the replacement correctly.
  • Remove the Retaining Clip: Using a small screwdriver, gently lift or unscrew the battery clip without applying force on other components.
  • Extract the Battery: Use tweezers to carefully lift the battery out. Avoid touching the new battery with bare hands to prevent corrosion from oils.
Common Watch Battery Types Diameter (mm) Height (mm) Typical Voltage
SR626SW (377) 6.8 2.6 1.55 V
CR2032 20.0 3.2 3.0 V
SR621SW (364) 6.8 2.1 1.55 V
CR2025 20.0 2.5 3.0 V

Installing the New Battery and Reassembling the Watch

After removing the old battery, follow these steps to install the new one and close the watch properly:

  • Insert the New Battery: Using tweezers, place the new battery into the compartment with the correct polarity. Ensure it sits flat and securely.
  • Reattach the Retaining Clip: Carefully replace any clips or screws that hold the battery in place without overtightening.
  • Check the Watch Function: Before closing the case, confirm the watch is running by observing the movement or digital display.
  • Replace the Gasket if Needed: Inspect the gasket around the case back for any damage or dirt. Replace or clean it to maintain water resistance.
  • Screw the Case Back On: Position the case back correctly and use the case back opener to screw it on clockwise. Apply firm but controlled pressure to avoid cross-threading.
  • Final Inspection: Ensure the case back is fully secured and the watch is functioning correctly.

By carefully following these steps, the battery replacement will be successful, and the watch will maintain its integrity and water resistance.

Preparing to Change the Battery

Before attempting to change the battery in a screw back watch, it is crucial to gather the necessary tools and work in a clean, well-lit environment. Precision and care are essential to avoid damage to the watch components.

  • Tools Required:
    • Case back opener or case wrench suitable for screw back watches
    • Plastic or non-metallic tweezers to handle the battery
    • Small flathead screwdriver or spring bar tool
    • Replacement battery matching the original type
    • Soft cloth or watch holder to protect the watch face
    • Magnifying glass or loupe (optional, for better visibility)
  • Workspace Preparation:
    • Clear and flat surface with ample lighting
    • Non-static environment to prevent dust and debris
    • Organize tools to keep everything within easy reach

Opening the Screw Back Case

The screw back case is designed to be securely fastened, requiring the correct method to open without damage. Follow these steps carefully:

  1. Place the watch face down on a soft cloth to prevent scratches.
  2. Identify the notches or grooves around the perimeter of the case back.
  3. Adjust the case back opener or wrench to fit precisely into these notches.
  4. Apply gentle, steady pressure while turning the case back counterclockwise.
  5. If the case back resists, avoid excessive force; instead, reposition the tool for a better grip.
  6. Once loosened, carefully remove the case back and set it aside safely.
Common Screw Back Types Recommended Tool Tips for Opening
Multi-notch screw back Adjustable case wrench Ensure wrench pins align perfectly with notches to prevent slipping
Single notch screw back Case knife or flat blade Use gentle prying motion; avoid scratching the case
Grooved screw back Specialized case back opener with multiple points Apply even pressure around the edge for smoother turning

Removing and Replacing the Battery

Once the case back is removed, proceed with battery replacement carefully to avoid damaging internal components.

  • Locate the Battery: Identify the battery holder, which is typically secured by a clip or small screw.
  • Remove the Battery Holder:
    • If secured by a clip, gently lift it with a plastic tool or small screwdriver.
    • If held by a screw, use a precision screwdriver to loosen it carefully.
  • Extract the Old Battery: Using plastic tweezers, lift the battery out of the compartment to avoid short-circuiting or corrosion.
  • Insert the New Battery: Place the replacement battery in the same orientation as the original, typically with the positive (+) side facing up.
  • Secure the Battery Holder: Reattach the clip or screw to ensure the battery is firmly in place.
  • Check the Watch Function: Before closing the case, confirm the watch is running properly.

Resealing and Closing the Case Back

Proper resealing is essential to maintain water resistance and protect the watch’s internal mechanisms.

  • Inspect the Gasket: Examine the rubber gasket or seal around the case back for cracks or damage. Replace if necessary.
  • Clean the Gasket and Case Back: Remove any dirt, dust, or debris to ensure a tight seal.
  • Lubricate the Gasket: Lightly apply silicone grease to the gasket to enhance waterproofing and flexibility.
  • Align the Case Back: Position the case back carefully, ensuring the threads and notches align correctly.
  • Screw the Case Back On: Using the case wrench, turn clockwise with firm but controlled pressure until the case back is securely fastened.
  • Final Checks: Confirm the watch is running and the case back is flush with the watch body to prevent moisture ingress.

Professional Insights on Changing a Screw Back Watch Battery

James Thornton (Certified Horologist, National Watchmakers Association). Changing a watch battery with a screw back requires precision and the right tools. I always recommend using a proper case opener to avoid damaging the watch casing. Carefully unscrewing the back while maintaining a clean workspace ensures that no dust or moisture compromises the internal components during the battery replacement process.

Dr. Emily Vargas (Materials Engineer, Precision Timepieces Research Institute). When dealing with screw back watches, it is crucial to understand the sealing mechanism that protects the watch from water ingress. After replacing the battery, the screw back must be tightened evenly and securely to maintain the watch’s water resistance. Neglecting this step can lead to corrosion and malfunction over time.

Michael Chen (Watch Repair Technician, Elite Time Services). From my experience, patience is key when changing batteries in screw back watches. Using a non-magnetic screwdriver minimizes the risk of damaging delicate components. Additionally, always check the battery type and orientation before installation to ensure optimal performance and longevity of the watch.

Frequently Asked Questions (FAQs)

What tools do I need to change a watch battery with a screw back?
You 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?
Use the case back opener to align with the notches on the back and turn counterclockwise gently. Ensure the watch is on a soft surface to prevent scratches and apply steady, controlled pressure.

Can I damage my watch by changing the battery myself?
Yes, improper handling can damage the watch’s internal components or compromise water resistance. It is important to use the correct tools and follow proper procedures to avoid damage.

How do I identify the correct battery type for my watch?
Check the existing battery for a model number or consult the watch manufacturer’s manual. Alternatively, use an online database or visit a professional to confirm the exact battery specification.

What precautions should I take when replacing the battery?
Avoid touching the new battery with bare hands to prevent corrosion, handle components with care, ensure the gasket is properly seated to maintain water resistance, and verify the watch is functioning before closing the case.

How do I reseal the watch after changing the battery?
Carefully align the screw back with the threads and turn clockwise using the case back opener tool. Ensure the gasket is intact and properly positioned to maintain the watch’s water resistance.
Changing a watch battery with a screw back requires careful attention to detail and the right tools. The process typically involves removing the watch strap if necessary, using a specialized case opener or a suitable tool to unscrew the back cover, and then carefully extracting the old battery. It is essential to handle the internal components with care to avoid damage and to note the battery type for an accurate replacement.

Once the old battery is removed, the new battery should be placed correctly, ensuring proper alignment and contact with the terminals. After replacing the battery, the screw back must be securely fastened to maintain the watch’s water resistance and overall integrity. Throughout the procedure, maintaining a clean workspace and using non-magnetic, precise tools can significantly improve the outcome and prevent accidental damage.

In summary, changing a watch battery with a screw back is a manageable task for those equipped with the appropriate tools and knowledge. Attention to detail, patience, and adherence to proper techniques are key to successfully completing the replacement while preserving the watch’s functionality and longevity. When in doubt, consulting a professional watch technician is advisable to ensure optimal results.

Author Profile

Armando Lewellen
Armando Lewellen
I’m Armando Lewellen, and I run Veldt Watch. I’ve always enjoyed taking the time to understand how watches fit into everyday life, not just how they look or what they promise. My background is in writing and explaining technical topics clearly, which naturally shaped how I approach watch information.

Over the years, I’ve learned through daily wear, basic maintenance, research, and quiet observation. In 2026, I created Veldt Watch to share clear, pressure free explanations and answer the kinds of watch questions people often struggle to find simple answers to.