Vintage glass metal ring

[arkobugg]

Cheers everybody!

In the lately I have done service on vintage Certina and Omega watches from the 50 and 60 s. And I see that many of this have an metal ring atteched to the glass or crystal. Can somebody tell me the purpose of this? What is it for?

 

Thanks and best...

 

[vinn3]

some times,  that holds the mvt. in the case.

[arkobugg]

Yes I can understand that, but  some I have seen have been on the inside of the glass..

Edited September 8, 2017 by arkobugg

[Chopin]

It's called a tension ring. It's supposed to keep the acrylic crystal "enlarged" so to speak so that it will stay inside the case when it's installed.

Modern watches usually have a gasket instead of the tension ring but back in the days they used that method so that the crystal wouldn't come out with ease after it has been properly installed.

You can find such crystals on cousinsuk for example. Golden for gold or gold plated cases and chrome for the rest (SS, chrome plated, etc.). Omega used quite a lot of these.

Edited September 8, 2017 by Chopin

[rodabod]

Yes, Sternkreuz make the "ATC" type which is standard low-dome. They also do high dome, wide ring (ooh err) and gold ring versions.

[arkobugg]

Thanks a lot for all help , then I understand what this is for...

 

Thanks and have a good day...

 

[Watchfixr]

A word of warning here.

In many Omega crystals the ring was relieved to fit around and center the dial. The outer edge of the ring will be level with the edge of the crystal, but the dial is slightly smaller and fits into the inner relieved area that is recessed. If you press a new crystal with a solid ring all the way home, you will crush the edge of the dial with the tension ring.