Open A Watch Case or Back

Need to open a watch case? Need to know how to open the back of a watch to change the battery? Just want to see what’s inside? Opening a watch back is similar across many types of watches. This particular how to is how to open wrist watch. Opening a pocket watch is quite different.

There are two basic types of watch cases, screw back and snap back. There are others, but we are only going to discuss the two most popular types of watch backs. In order to open a watch case with these types of back you will need a watch back removal tool:

Here you can see the blue ball called a Watch Case Opener Friction Ball which is very useful and removes over 50% of the screw back cases I run into. Just to the right of that you see the Jaxa Type Watch Case Back Opener which will take off the other 50% of screw back cases with its bag of interchangeable tips. On the bottom left is what is called a watch case knife and will open the snap back cases.

How to open a screw back watch? Here is a typical screw back case. Note the notches where a tool would fit to remove the case. Other forms of screw back cases look something like a large nut with sides or lands for something like a wrench to grab. We can usually use the same tools for both.

On a screw back case the first tool to open watch case to try is the ball, this is also how to open a watch back without notches. This is not an ordinary ball, the rubber is very grabby and it is soft enough to mash into the back and grip very tightly. Many times this ball can open a watch case without any difficulty, avoiding scratches. Press the ball firmly into the back of the case while supporting the front with your other hand like this:

Case gripping ball used for opening a watch case

Now twist the ball counter clockwise to unscrew the back. If that does not work we need to use the bigger tool. If the ball won’t open a watch case we reach for the watch case wrench which is how to remove watch back with notches if the ball fails. Many of these use removable tips. There are several tips like this:

The first and third tips can be used top open a watch case with notches in the back, the fourth is great for watches with lands or sides. I have never used the second one for anything.

Since this watch has notches and the first point fits in the notches very well we place all three of these tips in the three holders on the tool (each of the tips above come in a set of three). When opening a watch back with this tool make sure by twisting the tool’s handle and the adjustment knob on top that all three tips are securely in place on the back of the watch in the notches like this:

Once you are sure it is grabbing securely hold the watch in a case holder or in your hand, and twist the tool counter clockwise. You can do the same thing on a watch with lands or sides by using the fourth tips shown above and tightening them on the sides. If opening a watch back with this fails seek immediate help and do not try to force it.

If the back spins and will not unscrew it could be a fake screw back case. Some cheaper watches have backs that look like screw backs but really are snap backs, and for that we need a case knife, or a snap back watch case opener. Take the case knife and insert it between the back and the rest of the case near a lug as shown below:

Using a case knife for opening a watch case

Push the blade in towards the center of the watch while twisting the knife away from you pulling the sharper edge of the blade towards you and down. If you look at the case back above you see it has the lands or sides I was talking about earlier, on this watch those are to make it look more expensive than it really is because this is really a snap back case.

I would highly suggest you practice opening a watch back for a while before you do it on a nice watch as it is easy to scratch the heck out of the back with a case knife. One other warning, a case knife is a special made tool, you can not use a standard knife to do its job. If you try, at best you will dull the heck out of your knife, at worst you can stab yourself, break the blade and have it fly into your eye, or worse. Always use the correct tool for the job and practice with it.

The other side of opening a watch back is closing them. Some you can just snap back in by hand with no problem. The real problem comes with tougher ones you may be tempted to use too much force on, even to the point of putting the watch crystal down on a desk or table and putting your body weight into snapping the case back on. This can, and very often does, cause the crystal to crack. To avoid that you need this tool:

This is a small hand watch case press. It comes with an assortment of different sized nylon pieces that can be used to make sure the tool fits the case correctly. Most of the time you just need to make sure that the nylon pieces are large enough to put even pressure on the top and bottom of the watch and you should be fine, like this:

Pressing the back on after opening a watch case

By applying the force evenly you run far less risk of cracking the crystal. If you use a nylon piece that is too small the force will not be applied evenly, if you use one too big, the lugs may get in the way and either snap off or cause the watch to sit unevenly and once again crack the crystal. If your crystal is already cracked even using this tool carefully will likely result in destroying the crystal.

One good point contributed by a reader is that some dies for some watch case presses contain a recess for the crystal so that the pressure is applied to both sides of the case and not the crystal. This is an excellent idea which even though I have not needed so far, I will certainly look into getting some.

So how to close a watch back without a press? You can support the case in such as way that the crystal is facing down and is not taking any force when you push down on the back. Be careful with this however because if the force is applied to the crystal, or the watch slips, it could break the crystal or worse.

If you like working on your watch and need a little inexpensive tool kit, try this tool kit.

Good luck!