I recently purchased a nice Seamaster 165.014. As I was disassembling it for cleaning, I noticed that one of the three tiny ball bearings under the bezel was missing. I know that ruby balls are available that serve this function, but they are fairly expensive, and I wasn't even sure the two remaining balls were rubies. I measured the diameter of one as best I could while in place, and purchased some 0.8mm ceramic ball bearings (silicon nitride). Too small. So I next tried some 1mm balls: perfect. The bearings are at (roughly) 1, 5 and 9 o'clock. Here's a shot of the missing 9 bearing:



Here are the tiny balls:



Bearing has been inserted:



I don't know if 1mm is the size of the original bearings, but when pushed it in (a) it didn't come out easily, and (b) it was exactly the right height, as seen here:



Here's a shot from the side after reinstalling the bezel:



And finally one from above:



The bezel was rotating fine with only two bearings, but it's nice to have it complete.

 

Where does one purchase assorted sizes of ceramic ball bearings?

 

I got these on eBay. I could only find one size at a time, not an assortment----but I didn't spend hours looking. Here's what I ended up getting:

ballsPurchases made through these links may earn this site a commission from the eBay Partner Network

 

Wow @wsfarrell looks like surgical job
I have never disassembled any of my watches. I would not dare
Congratulations and thank you for posting this!

 

I am globsmacked!

And tricked by the thread title too!

Ruby balls! I’m going to try to make that my go-to exclamation when the unexpected occurs.

 

And I thought it was gonna be a thread about locker room insecurity...