Omega Seamaster Case, Flexible Ring Question

[systeman]

Hi all,

 

If you've read my other posts you will know I'm new to watch repaires.

 

I've just aquired an Omega Seamaster 166.003 case and seperated it into its component parts to give it an ultrasonic clean.

 

Three parts went into the bath and four came out, the fourth being a flexible metalised ring, it looks like a metalised plastic of some sort. It isn't the case back gasket because I'd already removed it. The only place it fits is the movement clamp groove.

 

What is it for?

 

Photo attached

 

I'm restoring another Seamaster which has the same casing and a 562 cal movement, and there was not a similar ring in that one.

 

[anilv]

Older watches used a lead ring to seal the caseback...but these usually don't come off in one piece.

 

Doesn;t look original.

 

Anil

[systeman]

Older watches used a lead ring to seal the caseback...but these usually don't come off in one piece.

 

Doesn;t look original.

 

Anil

 

This is not a case back seal because of its diameter. Under close inpection it seams to be a two part laminate with some sort of ahesive between the layers.

 

I can see a couple of indents on its inner edge and these seem consistant with the width of movement case clamp ends.

 

I think it was used as a shim and fitted in the same groove as the movement clamps to minimise any up/down and side play play.

 

Actually, I do think it's original.