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Eterna Caliber 520u

Eterna Caliber 520U

Eterna Caliber 520u

BrandEterna
Caliber Number520U
Base Caliber
Eterna 520
Movement TypeManual wind, mechanical
Diameter12”’ (26.5mm)
Thickness4mm
Jewels15
Lift Angle42 degrees (needs confirmed)
Power Reserve42 hours
Vibrations Per Hour18,000 bph
Balance StaffU620
HairspringFlat
Hands1.38mm / 0.80mm / 0.13mm
Anti-ShockEterna-U Device
FeaturesHours, minutes, small seconds
Country of ManufactureSwitzerland
Production Years1940s – 1950s
Known Models1952 Eterna dress watch

The Eterna caliber 520U is a vintage mechanical movement based on the Eterna caliber 520. These calibers were produced in the 1940s and 1950s.

Anti-Shock

The 520U movement seen here is equipped with an in-house anti-shock device called Eterna-U.

Other Variations

There are a few variations of the 520 movement with a letter designation based on the type of anti-shock device used. The ones we know about are:

  • 520 – the base caliber (4mm height)
  • 520H – Eterna-H shock absorber
  • 520L – Eterna-L shock absorber
  • 520S – central sweeping seconds (4.95mm height)
  • 500U – shown here

If you know more about these variations of the caliber 520, or know of some not listed, please leave the information in the comments.

The movement pictured above was found in a vintage Eterna dress watch here.

https://www.youtube.com/watch?v=IKHPZq4zuL0

About Eterna

Eterna was founded in 1856 in Grenchen, a municipality of Solothurn, Switzerland. Despite many people thinking that Eterna is part of the Swatch Group, the watch brand is owned by a Hong Kong watch conglomerate known as Citychamp Watch & Jewelry Group. ETA, the movement branch of Eterna that was established in 1932, became part of the Swatch Group and still produce movements that we know today. Eterna also still produces movements and modules for modern timepieces.

Please share your experiences and thoughts about the Eterna caliber 520U in the comments section below…

Caliber submitted by wahawatches.com

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Service: Eterna Dress Watch with In-house 520U Movement - WahaWatches
• 1 year ago

[…] movement is the Eterna 520U with 15 jewels and a hidden ratchet wheel and crown wheel. It’s Eterna’s first caliber […]

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What Watch to Wear to a Job Interview - WahaWatches
• 11 months ago

[…] presumably the most versatile watch that I own. A 1952 Eterna ref. 106BDT, with Eterna’s in-house calibre 520U inside. It’s understated, but neither not enough nor too much. Just a simple watch in excellent […]