Eterna 1158 Calibre: A Vintage Automatic Gem
The Eterna 1158, produced from 1945 to around 1948, represents a pinnacle of post-war Swiss innovation for vintage watch enthusiasts and hobbyist watchmakers. This bumper automatic movement, often denoted as 1158H, features Eterna’s pioneering half-rotor design—a hallmark of the brand’s 1940s engineering prowess. Its robust construction and distinctive Spider bumper system make it a sought-after piece for restoration projects.
Historical Context
Launched immediately after World War II, the 1158 bridged Eterna’s wartime manual calibers (like 1077) and postwar automatics.
Part of Eterna’s bumper family, it utilized a semi-circular rotor that swung freely until halted by a spring-loaded bumper, ensuring efficient winding without overstress.
Commonly found in 36-38mm steel or gold-filled cases, it powered elegant dress watches prized for their slim profile and reliable performance.
Technical Specifications
Type: Automatic with bumper self-winding (manual wind capability).
Size: 11.5 lignes (approx. 25.6mm diameter); height around 5.5-6mm.
Jewels: 17-19 jewels, including cap jewels for key pivots.
Frequency: 18,000 vph (5 Hz), providing smooth seconds hand motion.
Power Reserve: Approximately 40-42 hours when fully wound.
Functions: Hours, minutes, central seconds; no date complication.
Rotor: Iconic “Spider” half-rotor with ball-bearing pivot for reduced friction.
Bumper System: Dual-arm bumper with shock-resistant mounts to prevent overwind damage.
Finish: Signed bridges with Geneva stripes; adjustable regulator for fine timing.
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Watch Parts Enquiry
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Stem, Crown, Hands & Spares might be available for this movement.
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