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The Encyclopedia of Horology

Movement record · Germany (Glashütte)

A. Lange & Söhne calibre L921.4

Partially verified

A three-quarter plate movement in German silver with gold chatons, blued screws and hand-engraved balance cock, laid out so that the asymmetric Lange 1 dial has each indication over its own mechanism.

Technical specifications

Diameter
Not recorded in a source consulted here
Height
Not recorded in a source consulted here
Jewels
Not recorded in a source consulted here
Frequency
21,600 vibrations per hour
Power reserve
Approximately 45 hours
Winding
Manual winding
Setting
Crown setting, with the outsize date advanced by a pusher
Escapement
Swiss lever
Balance
Screwed balance with swan-neck fine adjustment
Complications
Outsize date, Power-reserve indication on the Lange 1 family

Identification features

  • Three-quarter German silver plate with hand-engraved balance cock
  • Twin barrels on some variants of the family

Known variants

  • Several numbered variants within the L901 / L921 family

Servicing notes

Factory service only; components are not available to the independent trade.

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

Historical significance

The calibre family with which Lange re-established Glashütte watchmaking after German reunification.

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. Manufacturer descriptions of the Lange 1 calibre family
  2. Variant numbering within the family is reported inconsistently outside factory documentation.

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