Eterna Caliber 520U

Brand	Eterna
Caliber Number	520U
Base Caliber	Eterna 520
Movement Type	Manual wind, mechanical
Diameter	12”’ (26.5mm)
Thickness	4mm
Jewels	15
Lift Angle	42 degrees (needs confirmed)
Power Reserve	42 hours
Vibrations Per Hour	18,000 bph
Balance Staff	U620
Hairspring	Flat
Hands	1.38mm / 0.80mm / 0.13mm
Anti-Shock	Eterna-U Device
Features	Hours, minutes, small seconds
Country of Manufacture	Switzerland
Production Years	1940s – 1950s
Known Models	1952 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.

• Eterna official site
• Eterna Wikipedia page

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

Caliber submitted by wahawatches.com