The ETA 2638 is a reliable automatic watch movement from ETA’s 2600 family, produced in the 1960s-1970s as a predecessor to the modern 2824-2.
Key Specifications
This 11.5 ligne caliber beats at 21,600 vibrations per hour (3 Hz) with a power reserve of about 38 hours and Incabloc shock protection. It features a sweep seconds hand, quickset day/date at 3 o’clock, and a lift angle of 52 degrees. Swiss-made, it supports manual winding alongside automatic operation via a bidirectional rotor.
Historical Context
Introduced during ETA’s expansion of workhorse movements, the 2638 belongs to the 26XX series, sharing traits like the 21,600 bph rate across variants (e.g., 2620 time-only, 2637 date-only). It powered numerous mid-range watches before quartz disruptions, valued today for serviceability and parts availability. Technical manuals reference it alongside base calibers like 2620.
Features and Variants
Complications: Quickset day/date for user-friendly adjustment; no hacking seconds.
Build: 17-25 jewels (depending on configuration), robust for daily wear.
Similarities/Differences: Matches 2632/2639 in auto day/date but in 11.5”’ size; hand-wound siblings like 2618 exist.
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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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