Skip to content
The Encyclopedia of Horology

Movement record · Switzerland

Unitas 6498

Partially verified

Large three-quarter-plate pocket-watch ébauche

Technical specifications

Diameter
16 1/2 lignes (approx. 36.6 mm)
Height
Not recorded in the sources consulted
Jewels
17 (variants differ)
Frequency
18,000 vph (2.5 Hz)
Power reserve
Approx. 45 hours
Winding
Manual, stem wind
Setting
Pendant set
Escapement
Swiss lever
Balance
Monometallic balance with alloy hairspring
Complications
Subsidiary seconds at 9 relative to the crown

Identification features

  • Large bridge layout with subsidiary seconds positioned for a pocket-watch dial
  • Commonly marked with the Unitas or later ETA designation

Known variants

  • 6497 with seconds opposite the crown
  • Later decorated versions for wristwatch use

Servicing notes

Cleaning, lubrication, mainspring and pivot work belong with a qualified watchmaker working from calibre-specific documentation. Conserve original parts: replacing a worn component with a modern substitute changes the object, and refinishing plates or dials destroys evidence.

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

Historical significance

One of the last widely produced large manual pocket-watch ébauches, and the movement that made oversized mechanical wristwatches practical late in the twentieth century.

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. de Carle, D., Watch and Clock Encyclopedia
  2. Period trade material catalogues and calibre reference compilations (edition-dependent)
  3. Published manufacturer technical documentation where available

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