Doned Square mineral glass. Can I cut / trim myself?

[Simeon]

I have picked up a small tank shaped Wittnauer watch which surprisingly has a double doned glass crystal. This is significantly scratched up and really needs replacement. Looking around it appears that my only option is a over-size Sternkreuz 'blank' that needs to be cut to shape. A flat mineral glass, I could cut using a standard glass cutter and then file to final size with a diamond file but not confident that I can do this with a double domed glass which would probably lend itself to grinding to size. 

Is this probably best left to a professional or is it something that I could feasibly do (without buying significant, expensive, tools)?

Alternatively, are there any practical ways of polishing a glass crystal? The scratches and dings are quite deep, so it would definitely need some kind of machine polish. 

 

[AndyGSi]

Are you sure it's glass?

Edit

What's the watch details and have you looked for an original replacement?

Edited September 18, 2024 by AndyGSi

[Simeon]

I don't know a reference number for the watch, other than it is a Wittnauer and fitted with a 10S movement.  It has a stainless steel back and no shock proofing, so I am guessing it is not as early as 1940s and probably not later than 1950 something.

Here is the eBay ad from when I bought it.

https://www.ebay.com.au/itm/176554789133

It definitely needs some work - the balance has a broken lower pivot and when I took it out, despite seemingly having a full wind there was no torque on the escape wheel - i flicked the pallet form back and forth but the escape wheel didn't seem to driven by the train. I haven't had time to examine it further than that but it looks like one of the wheels in the train is locked up for some reason or there is no force being applied by the mainspring.

34 minutes ago, AndyGSi said:

Are you sure it's glass?

Edit

What's the watch details and have you looked for an original replacement?

It;s definitely glass. I was expecting acrylic but was surprised to find glass (I did the tap on your tooth test)

[AndyGSi]

What size is the crystal?

[rehajm]

I’ve done it because replacement seemed impractical, with a curved tank glass like yours. I just used the poly watch glass kit and much effort. I suppose it depends on how deep the scratches are and the quality of result you’re looking for…