


Eterna 957S: A Vintage Powerhouse for Enthusiasts
The Eterna Caliber 957S stands as a pinnacle of mid-20th-century Swiss horology, cherished by vintage watch collectors and hobbyist watchmakers for its robust construction and innovative self-winding mechanism. Produced primarily in the 1940s and 1950s, this automatic movement powered iconic Eterna-Matic models, introducing one of the earliest bidirectional rotor systems that revolutionized wristwatch reliability.
Historical Context
Eterna pioneered automatic winding in the 1940s with the “Eterna-Matic” line, where the 957S variant emerged as a refined evolution. Its design emphasized durability for everyday wear, featuring the proprietary ball-bearing rotor mounted on five tiny bearings for smooth, silent operation. Hobbyists value it for straightforward servicing, with parts like balance staffs still available from specialists.
Technical Specifications
Type: Self-winding automatic mechanical movement
Jewels: 18-21 (depending on variant)
Diameter: 11.75 lignes (approximately 26 mm)
Height: Around 4.5-5 mm
Frequency: 18,000 vibrations per hour (vph)
Power reserve: Approximately 40-45 hours
Balance: Glucydur with flat Nivarox hairspring; Eterna-U shock protection
Rotor: Bidirectional, oversized polished design with Eterniflex mainspring
Functions: Hours, minutes, central sweep seconds; no date complication
Finishing: Perlage on plates, clean architecture with minimal 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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