How to Safely & Properly Open Your Screw-Back Watch Case

In the world of watchmaking, no niche has emerged far more in recent years than DIY modding.

Today, more and more parts of modern watches can be handled and treated by anyone through thorough guides, necessary tools, and enough patience. From strap changes to dial replacements, the number of different tasks or issues that you can handle is many thanks to the accessibility that manufacturers employ in their pieces.

Among all the different tasks that you can deal with while taking care of your timepiece’s needs, there’s one that may understandably seem quite daunting to deal with: opening a screw-back watch case.

Why you may have to open your screw-back watch case sooner or later

This task typically comes up over time because it’s necessary for carrying out other maintenance-related procedures, such as diagnosing issues on a mechanical piece or swapping out a battery on a quartz.

Although doing this task doesn’t necessarily arise as often as other more straightforward procedures like cleaning or polishing, you’ll still need to open your screw-back watch case up at some point in time eventually. What makes this task understandably intimidating, however, is that it requires finesse and patience because not having one or both can lead to costly mistakes and irreversible damages.

Thankfully, opening up the case of your excellent piece as safely and swiftly as possible is far less complicated than many others expect, ashaving the steps in mind can quickly go a long way!

A step-by-step guide to follow

If you want to open up your screw-back watch case for inspection, battery replacement, or a quick clean, here’s a step-by-step guide you can stick to:

Step #1: Get all the right tools together

Before you even consider opening up your precious timepiece’s case for whatever reason, it’s imperative to have the necessary tools so that you can safely do so. If you find that you’ll be doing this often, then it’s essential to invest in a friction ball, case holder, common shop vice, and case back wrench if you want to get the job done smoothly.

Step #2: Start things off with the friction ball

When you want to open the case, you’ll need to flip your piece over, grip it with one hand, and apply the friction ball against the case back. Now that you’ve gotten everything in place, you can hold the ball, apply some pressure on it, and rotate the friction tool counter-clockwise to get the back to come off quickly.

Step #3: Consider the workspace set-ups and extra elbow grease

If the case is barely giving in, it is recommended that you first set up your workspace and case holder, and apply slightly more elbow grease with a case back wrench.  
Once everything in your workstation is set-up correctly, you’ll need to pin down your watch face-down on the case holder’s nylon pins so that it doesn’t move around. You’ll need to match the grooves on your case with the right chuck and size up the tool to the case’s back to use the case wrench. If there’s a bit of looseness on the device, you’ll need to re-adjust the wrench’s thumbwheel until everything lines up nicely!

Step #4: The opening

Now that your case back wrench is set up, you can open the case back by applying a mild degree of downward pressure with your wrench hand while moving it counter-clockwise. You must exercise a higher degree of care in this step to ensure that you don’t scratch the case back or warp it!

By the time that you’ve finished these steps to open the case up, carry out the steps in reverse, and you’ll end up with a reassembled screw-back timepiece in no time!


Dealing with a screw-back watch case is an essential skill that any collector, hobbyist, or wearer should learn sooner or later. Through the help of this cohesive step-by-step guide, you’ll be able to safely and successfully carry out a case back removal to replace your battery or inspect your watch! We’re the leading supplier of Seiko mod parts in Europe that offers various types to make any model as unique as can be, whether it’s a Tuna, Turtle, Mako, or Sumo. Bring out your creativity and escape ubiquity in the world of Haute Horlogerie by visiting our website and ordering mod parts for your watch today!

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