Selecting The Right Crystal

[harrison72]

Hello all,

over the past 3 years, with Mark's videos as inspiration I have managed to save several watches from the bedroom drawer to being worn by their owners. Nearly all have benefitted  by fitting a new crystal. No problem  with a named watch  ( like say a Tissot Seastar 7) but not so easy for a 1900's pocket watch, or an obsolete watch with no spares support. Since this is a topic which concerns nearly all of us, is their a guide to crystal selection particularly detailing the type of edge required to fit the bezel/case/tension ring and the use or not of cement to secure the crystal, the choice between acrylic or glass, hi/low dome, thickness  etc?

[BeyondWorld]

Normally I do all my watch glass replacement by guess work, I don't know of any guides that can help.

 

Armoured glasses belong in waterproof watches.

 

Low dome go in most vintage watches (If possible I normally always go low dome unless I don't have the correct size)

 

Extra think high dome armoured glasses go in super compressor divers watches - These are extremely rare, I only have a couple and don't like to waste them. I've been looking for a year a 340 sized one to fit in my first model iwc aquatimer. I managed to make one for my longines nautilus divers that looked just like the original, but I consider that to be pure luck. The inner rotating bezel doesn't work without this special glass.

 

High dome are only used if hands touch the glass.

 

Flanged glasses go in military watches where you unscrew an inner glass ring.

 

Rolex glasses are specially sized, they have a thin edge where they pop between the case and bezel.

 

And glass glass go in early trench watches or pocket watches, the cases have a tiny lip where you pressure fit them in.

 

I think cement should only be used for rectangular watch glasses, or other unusual shapes.

 

- That's my view on all watch glasses

Edited February 23, 2016 by BeyondWorld

[bobm12]

 

I think cement should only be used for rectangular watch glasses, or other unusual shapes.

...and some fancy/inexpensive/fashion watches even round ones.  :)

 

Great post BeyondWorld!

 

Cheers,

 

Bob

[harrison72]

thanks for the info BeyondWorld. Any similar tips from anyone welcome, we might end up with a practical guide.

I'm still a bit baffled by the choice, looking at the Sternkreuz range, they do at least 16 series of types often with multiple choices in each type. The specials (ie Rolex)  are less trouble as they are self selecting.  A typical 60's swiss watch with a  recessed bezel into which the glass fits do you use a "snap in "acrylic, or mineral glass? Do you measure the watch recess diameter and add some amount to the glass to make it stay in place? if so how much excess? Is it the same for acrylic and mineral glass?

I made an error recently ordering a glass for a pocket watch, 0.2mm over size, spent about an hour carefully reducing it to fit ,then found the outer case wouldn't close because the glass was too high!