CWC W10 crystals

[Bill241]

I’ve just taken delivery of my next project: a 1977 Army issue CWC W10. Like most of these, this is a bit careworn but I’m looking forward to overhauling the ETA 2750, and giving the rather mucky case a thorough clean. It’s a monocoque case design and, from what I’ve seen, unlike similar Seiko and Omega watches, which have movement retaining features incorporated into the case, this relies entirely on the crystal to hold the movement in the case. 

The crystal is a poor fitting replacement and I want to fit something appropriate, with a tension ring. I’d rather not rely on the current crystal as a guide for ordering a new one. Would anyone happen to know which Sternkreuz crystal is appropriate for this model? 

[rehajm]

Sorry there’s no definitive answer - I’d like to know for certain as well…

I’m in the US but another forum mentioned acquiring cwc crystals from Silvermans in UK? 

…and I don’t know if the CWC crystals are similar to the Smiths W10, which has the chrome ring. For the Smiths I ordered the Sternkreuz ATC (size 316) which looks like the proper dome but the tension ring is chrome. I’ve seen a post where for the CWC they reused the original ring, which I see is not chrome and the original may make a difference in securing the front loader…

The ATC are like 9 quid from Cousins, so you could check your measurements and give it a try…

Edited September 28, 2023 by rehajm

[Bill241]

Many thanks. I did ask Silvermans who were most polite but they don’t support these older watches now. They pointed me in the direction of a certain watch repairer but I’m confident I can do it myself. It’s keeping good time but with an amplitude below 200 degrees so a clean, new mainspring and fresh oil should help. 

Here’s a photo of the watch with the incorrect crystal. With the aid of air pressure delivered via syringe, I’ve just popped it off to have a look. There’s no tension ring and my vernier caliper reads 30.5mm, so I’ve ordered a Sternkreuz ATC 305. The chrome ring might stand out but will be a reassuring reminder that the glass and movement won’t fall out any time soon!