Bonus Ep.6 Stem Extensions

In this episode we will cover the replacement of a watch crown.

From time to time, it may be difficult to find the exact crown and stem combination in order to repair a broken watch winder.

This video demonstrates the use of stem extensions in watch repair and the ideal situations which may warrant their use.

We go through all the measurements needed and demonstrate an effective method of installing the stem extension to the crown and stem.

This is a bonus video for those who have completed Level 1 of the watch repair course, but if you are a Patron you can also view this video as one of your perks.

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  • Thanks for that really informative video on stem extensions. I have an almost related question: where a stem has broken off flush in a crown is there any practical way of removing it or is the only way to replace the crown. I have a Perona watch with the original crown with the maker’s mark on it and it would be nice to keep the crown if possible.

    • I have had sucess by using ‘Alum’ solution. I got this from the local chemist (UK). I was wary about asking them for dodgy chemicals, but they were fine about it. It’s a white powder which you add to water and let the crown soak. I can’t remember if it just dissolved the stem, or if I had to get it out with tweezers – I’m sorry, but it was years ago.
      I got the tip from and old book if I remember.
      I know that this is a watch forum and this is my first post. I’m just starting to take a more serious interest in the subject, ut I have ‘dabbled’ in the past. If I’m way off the mark here, please can someone with more knowledge correct me.
      I hope that this works for you.

  • I did not know there were stem extensions.

  • Hi, Mark. It’s always a delight to watch your videos. I’m finishing the basic classes and will continue my learning path with you!
    I have bought a Wyler Incaflex Dynawind wristwatch and was venturing into dismantle it and clean it when I’ve faced a problem, I can’t remove the movement from it’s case because of not being able to disconnect the stem!
    I had to remove the dial/face to have access to the mechanism but there’s no dotted lever to push and it comes out. Also, had to remove the date wheel to look for it and, sure enough, the date jumper spring is now MIA!!! Where do you buy any parts for a watch like this?
    The search and rescue team is still working on finding the damn “U” shaped spring but very discouraged ?
    Anyway, another great video! You’re a godsend hero for the watchmaking community!
    Cheers from Florida USA ??

  • Are stems (almost) always secured into the crown with red Loctite? If so, I’m surprised you just unscrewed the original stem without applyling quite some heat?

  • How are you measuring the male / female threads on these components? Just the diameter? Trial / error with components with known threads? Are there different pitches?

    • A

      With watch stems they are fairly standard. Tap 9 is most common and there will not be different pitches. You will find Tap 7 (mainly found in quartz watches),8 and 10 being somewhat less popular. Tap 12 is sometimes found with older watches.