Eterna Caliber 1237: A Vintage Automatic Marvel
Vintage watch enthusiasts and hobbyist watchmakers cherish the Eterna Caliber 1237 for pioneering self-winding innovation in the late 1940s. Launched around 1949 as part of the groundbreaking Eterna-Matic family, this movement brought silent, bi-directional winding via a ball-bearing rotor to men’s watches, revolutionizing reliability and smoothness.
Historical Context
Developed in collaboration with ETA engineer Heinrich Stamm, evolving from smaller ladies’ calibers like 1194/1198.
First full-size automatic with a five-ball-bearing oscillating weight, becoming Eterna’s enduring logo symbol.
Produced until about 1953, when superseded by thinner 1413-series; variants include suffixes T, U, C for rotor and shock upgrades.
Featured direct-driven central seconds, a rarity then, enhancing visual sweep and precision.
Technical Specifications
Size: 10.5 lignes (approx. 23.1 mm diameter).
Height: Approximately 5.2 mm (thicker due to top-mounted winding bridge).
Jewels: 17–21 (base 17; date variants higher).
Frequency: 18,000 A/h (5 Hz), with Glucydur screw balance and Nivarox hairspring.
Power reserve: Around 40–45 hours.
Winding: Bi-directional automatic via Eterniflex mainspring and reverser; manual wind option.
Functions: Hours, minutes, central seconds; date quickset on some (e.g., 1237 with calendar).
Escapement: Lever pallet; Incabloc or Eterna-U shock protection (upgraded post-1949).
Finish: Polished bridges, blued screws; gear train rated highly for durability.
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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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