By Montredo in Watch 101
May 14, 2019


Here is the thing with watches. They are not designed to be opened regularly. If your watch is still under warranty we recommend not to open the watch by yourself. And why would you? If you have a problem with a new watch, you can always contact an authorized dealer to take care of this matter. Having said that, there are still reasons why you would want to take a look at the movement of a used watch, for example, if you want to check the superficial condition or if the movement is correct for a certain reference or serial number.

Now how are you going to open your watch? First of all, make sure that you have a watch with a screw-down caseback. How can you check this? Look at the back of the watch. If there are small indentations around the reverse of the case, then your watch has a screw-down caseback. If there are no indentations visible you likely have a watch with a snap-off caseback.

Longines Conquest GMT | Ref.: L3.687.4.56.6

So, what do you need to open a screw down case back? Basically, two things: A watch case wrench and a case holder. As you can see the bracelet of the watch has been removed here. It’s not absolutely necessary to remove the bracelet before you open a watch case but it might be easiest way to do it and will help us for illustration purposes.

First, securely place the watch case in the watch case holder and make sure that the watch is held tight and can’t move. If it is not tight enough this may result in stains or even smaller dents. However, this doesn’t mean that you should put as much force on it as you can, as this can also potentially damage the surface of the watch case. As is often the case, it’s all about striking a happy medium.

Now grip the watch holder with your weaker hand and use the other hand to hold the wrench and slowly try to turn it counterclockwise in order to open the watch. Once fully opened, you can now lift off the case back with your hand. While grabbing the disc, make sure that you don’t touch the delicate mechanics of the movement. We recommend keeping the watch in the watch case holder as long as the watch is open. This way, you will not have to fix the case onto the case holder again, once you will close the watch.

When closing the watch, we recommend turning the case back in the opposite direction first to make sure it locks properly into place. Once it’s latched evenly, make sure that you screw the caseback tight enough to ensure that no water or dust can enter. You can apply some force but please be careful not to overdo this, as this could potentially cause damage to the watch. Usually, you will start feeling a stronger resistance once you have reached the seal ring. You can then still continue to screw until you have reached a point when the caseback would not move any further unless you use brute force. This is the case once the metal of the caseback disk touches the watch case. Once this is the case your watch case is fully closed and you can remove the watch from the case holder.

Longines Conquest GMT

Brand: Longines
Reference: L3.687.4.56.6
Case diameter: 41 mm
Case Material: Stainless steel
Glass: Sapphire
Caliber: L704.2
Movement: Automatic