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The Encyclopedia of Horology

Movement record · Switzerland

ETA 2824-2

Verified

A compact automatic calibre with a ball-bearing-mounted rotor and reversing wheels, supplied in several finishing grades from Standard to Chronometer and used by a very large number of brands.

Technical specifications

Diameter
Approx. 25.6 mm (11½ lignes)
Height
Approx. 4.6 mm
Jewels
25
Frequency
28,800 vph (4 Hz)
Power reserve
Approx. 38 hours in standard specification
Winding
Automatic, bidirectional, with hand winding
Setting
Pull-out crown with quickset date
Escapement
Swiss lever
Balance
Glucydur-type balance with Nivarox hairspring, specification varying by grade
Complications
Date, Centre seconds with hacking

Identification features

  • 2824-2 marking on the automatic bridge or rotor on unmodified examples
  • Rotor and reversing-wheel layout familiar from countless brand-modified versions

Known variants

  • Standard, Elaboré, Top and Chronometer grades
  • Brand-specific modified versions with altered rotors and regulation

Servicing notes

Very well documented with excellent parts supply, which is a substantial part of its appeal; grade differences affect regulation expectations, not basic servicing.

General guidance only. Antique movements should be serviced by a qualified watchmaker.

Historical significance

The workhorse automatic calibre of the post-quartz mechanical revival and the usual benchmark against which other modern automatics are judged.

Diagram

top plate or bridgespillar platebalance and cockwheel train between the plates
Schematic: plate and bridge layout. An outline schematic drawn to show the arrangement of the parts discussed here. It is not a dimensioned working drawing and does not depict a particular maker's calibre.

Sources & references

  1. ETA technical communication for calibre 2824-2
  2. Power-reserve and rate figures differ slightly between grades and revisions.

Where sources disagree, the disagreement is stated rather than resolved silently.