Eterna Caliber 520: A Vintage Gem for Enthusiasts
The Eterna Caliber 520, introduced in the early 20th century, marks Eterna’s pioneering step into gents’ wristwatches. This manual-wind mechanical movement captivated hobbyist watchmakers with its slim profile and innovative hidden ratchet wheel design, blending Swiss precision with elegant simplicity. Vintage collectors prize it for its role in early dress watches, often housed in gold or steel cases from the 1920s-1940s.
Historical Context
Debuted as Eterna’s first wristwatch caliber, transitioning from pocket watches to wearable timepieces.
Featured both old and new mounting threads in later variants, easing retrofits in diverse case designs.
Commonly found in Eterna dress watches, like those in 9K gold Dennison cases with patinated dials.
Technical Specifications
Type: Manual wind, mechanical.
Diameter: 12”’ (26.5 mm).
Thickness: 4.00 mm—exceptionally slim for its era.
Jewels: 15.
Lift Angle: 42 degrees.
Frequency: 18,000 vph (5 Hz).
Power Reserve: Approximately 40-45 hours.
Key Features: Hidden ratchet and crown wheels under the balance cock; swan-neck regulator; blued screws.
Appeal to Hobbyists
Restoration Ease: Compact size suits servicing on workbenches; parts remain available via specialists.
Unique Traits: The concealed winding mechanism reduces dust ingress, ideal for case refurbishments.
Collectibility: Serial numbers aid dating; pairs well with period complications like sub-seconds.
Servicing Tips
Disassemble balance first to access hidden wheels—avoid forcing the mainspring arbor.
Use rodico for cleaning bridges; pegwood for pivots. Regulate to -10/+15 sec/day on timing machines.
Source donor movements for spares, as Eterna 520U variants share components.
For any Watch Spare Parts inquiry, Email us for rate and availability: [email protected]
Watch Parts Enquiry
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Stem, Crown, Hands & Spares might be available for this movement.
Email us for rate and availability: [email protected]
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