How To Add Watch Stem Extenders And Crowns

In this post I will show you how to add watch stem extenders and crowns to repair broken stems in watches. I will also point out to you the required tools and parts in details. We will work on a SEIKO 7N00 F060 which I have received for repair from a client. It is a vintage Seiko watch. The stem from the watch was broken in half and the client lost the stem along with the crown.

Unfortunately, it is very difficult to get the same stem and crown. Sometimes you can find a particular part on eBay but it also takes too long to arrives and you might lose the client. But if you’re trying to repair your own watch, then no problem.

How to add watch stem extenders?

1. Open the watch case. Please read:

How to open a watch case? Do It Yourself

2. Locate the setting lever and press the dimple to release the part of the stem which is left in the watch. See the red circle in the image below. The dimple is there.
setting lever dimple

Hold the dimple with a pin or tweezers, pull the stem and remove it from the movement.

3. Rub the back part of the stem on a polishing bar in order flatten the back of the stem so that the external thread of the stem can be smoothly adjusted with the extender. Most quartz movements uses stems of 0.9 mm, other flat movements may use 0.7 mm. So make sure you get the correct size when you’re buying watch stem extenders.

You can get a lot of 0.7 and 0.9 mm watch stem extenders on AliExpress at cheaper prices.

How to add crowns?

4. Get a matching crown. You may buy an assorted box of waterproof crowns and surely you will find a matching crown in it to fit in your watch.

watch stem extenders

5. Now that you have all the required parts, its time to adjust them. First, fix the extender with the crown. Hold the extender with a nose plier and mount the crown with your other hand. Now that they are fastened together, mount the main stem to the extender by holding the main stem with a nose plier and turn the crown with your other hand. The result is:

6. You will have to cut and make the length of the whole stem match the watch case. To do so just remove the crown from the stem and cut the extender little by little till you get the desired length. After every cut rub the stem on a polishing bar before fastening it to the crown. Don’t cut the stem too much on the first time as it might become too short.

7. Insert it into the movement and done. Another happy customer!

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