Eterna 1429u replacement crystal

[ITProDad]

The Eterna is going well. But I need a replacement lens. However, I don’t know anything about wrist watch crystals. I have thousands of pocket watch crystals but none are domed like the original on the 1429u. It measures 31.5mm in diameter and 4.5mm high. I checked Cousins and could not find one. Any ideas would be appreciated.

 

 

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[jdm]

If isn't cracked just polish it.

[clockboy]

There are several vids on youtube made by Mark on the various styles and how to fit and measure.

[WatchMaker]

In general you'll either be dealing with an acrylic crystal that's got a tension ring ... or not. Yours seems to be the latter case which takes us here: https://www.cousinsuk.com/category/acrylic-round-domed-watch-glasses

I can then tell you that you're after one of the High Dome series crystals i.e. HW or HWS*. These are effectively the same but the latter has a small 'step' around the perimeter. Yours looks like it might be one of these but I can't be totally sure as it could just be reflection in your first pic! Anyway, it's easy enough for you to confirm this with your existing crystal i.e. it will either just come down from the dome in a uniform way (HW) or come down from the dome with a small step (HWS).

After accurately measuring the diameter of your crystal you should then get the size that is 0.1mm larger to ensure that, with a claw fitting tool, you maintain a tight fit crystal-to-case.  You say your crystal is 31.5mm so you'll need the 31.6mm crystal ... so that's either Cousins item HW316 or HWS316 subect to your confirmation of my comments in the last paragraph.

Because these crystals are so inexpensive you'll probably want to go with a new one but @jdm is quite right that polishing can achieve good results and get something with (light) scratches back to looking like new. Polywatch is a good product but some people just use toothpaste!

*Although the Sternkreuz catalogues are available for download (e.g. direct or from a site like Cousins) they're still a bit rubbish for certain specific details measurements. I've double-checked with an HW crystal I have in my spares box to confirm it's 4.5mm high!

 

[ITProDad]

If isn't cracked just polish it.

It is acrylic and it is entirely spider webbed in cracks across the entirety of the lens. I want to replace with glass. So I’ll have to be careful with the measurements, so as not to flex the existing lens while using the caliper.


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[yankeedog]

56 minutes ago, ITProDad said:

 

It is acrylic and it is entirely spider webbed in cracks across the entirety of the lens. I want to replace with glass. So I’ll have to be careful with the measurements, so as not to flex the existing lens while using the caliper.


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Measure  the inside diameter  of the case as well  between  3 and 9,and again  between  12 and 6. It is after all this hole  you need  to fit.

Edited January 15, 2020 by yankeedog

[jdm]

1 hour ago, ITProDad said:

It is acrylic and it is entirely spider webbed in cracks across the entirety of the lens. I want to replace with glass. 

 

Mineral high dome is not very common, but check https://www.aliexpress.com/item/4000590727449.html
Or may os cheaper on Ebay.

[vinn3]

13 hours ago, ITProDad said:

 

The Eterna is going well. But I need a replacement lens. However, I don’t know anything about wrist watch crystals. I have thousands of pocket watch crystals but none are domed like the original on the 1429u. It measures 31.5mm in diameter and 4.5mm high. I checked Cousins and could not find one. Any ideas would be appreciated.

 

 

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    in my experence with pocket watches.  there is - glass flat ( and domed) AND plastic ( acrilic ? )      vin