The Eterna Calibre 1435 (often marked as 1435 K) is an elegant, small-diameter manual wind movement designed for vintage ladies’ watches, produced in the early 1960s and prized today for its refined construction and resemblance to the ETA 2412 family.
Why watchmakers value it
This is a compact, high-beat movement (21,600 A/h) that offers excellent timekeeping potential, especially when properly regulated and serviced.
It shares design DNA with ETA 2412, so parts and tools for ETA 2412 are often helpful when working on the 1435, though direct substitution must be verified.
The movement features a Glucydur annular balance, which is stable and corrosion‑resistant, giving it a classic, high‑quality feel under the loupe.
Being manually wound, it has a simple, robust gear train and is generally easier to disassemble and reassemble than automatics, making it a good practice movement for hobbyists.
Practical notes for servicing
The movement uses a yoke winding system; the setting lever spring is typically a 3‑hole type, so spares for ETA 2412‑family movements may fit.
Special attention is needed on the hairspring stud and regulator arm: the stud is movable, and the long regulator arm sits fairly deep, so don’t force it during adjustment.
The escapewheel is jewelled (cap jewel), while the minute train runs in metal bushings, so bushing wear in the motion works should be checked during servicing.
Shock protection is KIF Ultraflex, which is a good, robust system for vintage pieces, but the jewels and pivots still need careful handling.
Technical specifications
Calibre: Eterna 1435 / 1435K
Type: Manual wind, round
Size: 7¾”’ (approx. 17.2 mm diameter)
Thickness: ~2.90 mm
Jewels: 17
Beat rate: 21,600 A/h (6 vibrations per second)
Escapement: Pallet lever
Balance: Glucydur annular balance, clockwise
Hairspring: Moveable stud, regulated by long regulator arm
Power reserve: ~44 hours
Winding system: Yoke winding mechanism
Production period: From around 1961.
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Stem, Crown, Hands & Spares might be available for this movement.
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