The ETA 2451 is a classic automatic watch movement developed by ETA in the early 1940s, marking a significant step in the evolution of Swiss automatic calibers. It is recognized for its robust construction, bidirectional winding system, and reliability, making it a favorite among vintage watch collectors and restorers.
Key Features
The ETA 2451 features an 11 1/2”’ (25.6mm) diameter and a height of 5.2–5.3mm, making it suitable for a wide range of case sizes.
It operates at a frequency of 18,000 vibrations per hour (A/h), with a typical power reserve of around 42 hours.
The movement is equipped with 21 jewels, though some variants may have 17, 25, or 30 jewels.
It uses a Swiss pallet lever escapement and a Glucydur balance wheel, often protected by Incabloc shock absorbers.
Construction and Operation
The ETA 2451 is known for its flat construction and center seconds display, achieved through a gear train that drives the seconds wheel directly.
The movement employs a yoke winding system, allowing bidirectional winding of the mainspring via a hollow conical axle and pawl changer wheels.
The hands are driven indirectly from the dial side, a design feature that persists in modern ETA movements.
The self-winding module is removable for servicing, and the oscillating weight is axle-beared, winding in both directions.
Historical Significance
Introduced in 1942, the ETA 2451 served as a pilot series for the family 690 through 699, influencing the design of later ETA calibers.
Its production period spanned from the 1940s into the 1970s, making it a staple in many vintage Swiss watches.
Bulletin Points
Automatic movement with bidirectional winding.
Diameter: 25.6mm, Height: 5.2–5.3mm.
Frequency: 18,000 A/h, Power reserve: 42 hours.
Jewels: 17–30 (depending on variant), typically 21.
Swiss pallet lever escapement, Glucydur balance, Incabloc shock protection.
Indirect hand driving, removable self-winding module.
The ETA 2451 remains a benchmark for vintage automatic movements, appreciated for its durability and influence on modern Swiss watchmaking.
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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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