Wittnauer crystal and gasket question

[Mike78]

A friend asked me to replace the crystal and clean up his Wittnauer watch.  I've done this on another watch of his and I guess he liked the result.  After removing the crystal. I found a rubber gasket below it.  

I wasn't expecting this and am now trying to understand where exactly the gasket is supposed to sit.  In the second picture you can see the gasket is sitting on the dial itself.  It appears the crystal is going to 

sit on the part I highlighted in red.  After reinstalling the crystal and taking a closer look, the crystal doesn't even contact the gasket leaving me a bit confused.  Any ideas how the gasket and crystal are supposed

sit?

 

Appreciated the help

[Jon]

It appears that the gasket has shrunk over the considerable amount of time it has been there. There would be no point in a gasket sitting on the dial and the crystal making no contact with it. I imagine that the gasket was under the crystal, but when you removed the crystal the gasket malformed into the shape and size you have now.

On a watch this age there is little chance of water tightness so a gasket under the crystal is of little use, so when replacing the crystal I wouldn't bother placing a gasket in there first and just fit the crystal as it is. You may find though that without the gasket the crystal sits too low and the second hand catches the underside of the crystal. In that case the gasket is needed for the correct height of the crystal off the dial.

I had this case on a job last week where the hands caught the underside of the crystal, so I made a stainless steel packing ring for the crystal to sit on out of an old tension ring you find in armoured crystals and it lifted the crystal away from the dial about 0.5 mm. Much better looking and blends in nicely rather than seeing a thin black gasket that might be seen.

[Mike78]

That makes sense.  I thought it was odd that the gasket was sitting on the dial itself.  I don't have the means of making a metal ring so I will try with gasket.  At least this way I can order the correct diameter gasket.  Appreciate the input Jon.