The Eterna 1031: A Pillar of 1950s Precision
Vintage watch lovers cherish the Eterna 1031 for its role in powering iconic mid-century timepieces from brands like Eterna, Rotary, and Nivada. Introduced around 1955, this manual-wind calibre embodies post-war Swiss innovation—slender, reliable, and beautifully finished. Hobbyists admire its accessibility for servicing, with parts still available through specialists. At just 11.75 lignes (26mm diameter), it fits elegantly into dress watches and chronometers, delivering smooth sweeping seconds and impressive power reserve.
What sets the 1031 apart? Its ball-bearing mainspring barrel reduces friction for superior longevity, a signature Eterna feature predating modern anti-shock systems. Disassemblers revel in the direct-impulse escapement, which minimizes energy loss for accuracy within chronometer-grade specs (+/- 10 seconds/day when regulated). The glucydur balance wheel resists temperature swings, ideal for vintage restorations where stability matters.
Technical Specifications
Type: Manual wind, 17 jewels
Dimensions: 26mm diameter, 4.5mm height
Frequency: 18,000 vph (2.5 Hz)
Power Reserve: ~45 hours
Escapement: Direct impulse with Glucydur balance
Shock Protection: Incabloc (on later variants)
Adjustments: 3 positions (dial up/down, crown)
Finishing: Blued screws, Geneva stripes on bridges
Beat Rate: 10 beats per second
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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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