The Eterna calibre 520 is a superb pre 1950’s movement and their last model featured modern shock protection. This watch is in decent condition, but in need of a service.
The movement is in decent condition. (I have already replaced the barrel bush when I did my last 520).
Here you can see the gear train with the train bridge removed.
The click and click spring is fitted on the underside of the barrel bridge.
Old mainspring.
After cleaning the movement I fit the cap jewels to see that the movement moves freely. I like this version the best as it provides the best shock protection.
Mainspring in the barrel.
Gear train comes back in place.
The crown wheel is fitted underneath it’s own bridge.
The construction of this movement must have been expensive as it has 3 individual bridges and a separate escape wheel cock.
Setting/winding mechanism back in place.
Movement back together and ticking.
Preforming well for a 60+ year old watch!
I suspect the dial was restored a long time ago and still looks very nice.
Someone fitted a tension ring crystal even though the watch should have a normal crystal.
Movement back in the case looking good!
For being a late 1940’s watch it has a rather large case diameter of 34.5mm w/o crown.
Super watch that would go well to most occasions:)
6 Responses to Service Eterna 520U
Hi Mitka,
Great walkthrough! Thank you for sharing. Question, did you have the case replated?
Gary
Hi Garry,
No need as it’s stainless steel. The discolouration on the case was grime that cleaned up:)
Best regards,
Mitka
Hi Mitka,
Great articles on your site. I wish you all the luck now that you are working independently.
One question, how do you know this watch should have a crystal without a tension ring?
Regards
Hi Dušan,
Thanks:)
You can tell by the grove the crystal is fitted in. Tension ringed crystals have straight edges while the normal crystals have a slant grove.
Best regards,
Mitka
Excellent site & information & first class work.
Thanks for the kind words David:)