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The Encyclopedia of Horology

Movement record · United States

Hamilton 992B

Verified

Three-quarter plate nickel movement with damascened finish, motor barrel and micrometric regulator; designed specifically to satisfy railway time-service requirements.

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Technical specifications

Diameter
16 size (approx. 43.1 mm)
Height
Approx. 5.8 mm
Jewels
21
Frequency
18,000 vph (2.5 Hz)
Power reserve
Approx. 40 hours
Winding
Stem wind (pendant set variants exist)
Setting
Lever set
Escapement
Swiss lever, exposed pallets
Balance
Elinvar Extra hairspring with monometallic balance
Complications
Subsidiary seconds

Identification features

  • '992B' grade marking on the barrel bridge with 'Railway Special' on many examples
  • Elinvar Extra marking on the balance cock area
  • Lever set visible after removing the bezel
  • Damaskeened nickel plates marked 992B with 'Railway Special'
  • Lever-set: the bezel must be removed and a lever pulled to set the hands
  • Montgomery-style dials common, with every minute numbered

Known variants

  • Early 992B with ionic dial
  • Late production with melamine dial
  • 992 (earlier, 1903–1940)
  • 992E (elinvar hairspring, made in the 1940s)
  • 4992B (24-hour military derivative)

Servicing notes

Parts availability is good relative to other American grades. The motor barrel requires correct disassembly; do not force the arbor.

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

Historical significance

Hamilton's best-known railroad-grade pocket movement: 16-size, 21 jewels, lever-set, adjusted to temperature and five positions; made from 1940 to about 1969 and widely accepted under US railroad time-service rules.

Photographs

Hamilton 992B, identified in the source as a 1944 example — exposed 21-jewel movement before workshop servicing
Hamilton 992B, identified in the source as a 1944 example — exposed 21-jewel movement before workshop servicing — HandyDan / Vintage Hamilton Watch Restoration (Hamilton Chronicles), Copyright workshop photograph — rights pending; reduced-size JPEG copy, permission not established. Hamilton Chronicles — exact 992B restoration record
Dial and exterior case of a Hamilton 992B railroad pocket watch
Dial and exterior case of a Hamilton 992B railroad pocket watch — Jack Stephens / Watchfinder & Co., Rights pending — permission not yet requested. Web page (watchfinder.com)
Hamilton 992B railroad pocket watch dial and case exterior
Hamilton 992B railroad pocket watch dial and case exterior — Jack Stephens / Watchfinder & Co., Rights pending — permission not yet requested. Web page (watchfinder.com)
Hamilton 992B railroad pocket watch movement
Hamilton 992B railroad pocket watch movement — Jack Stephens / Watchfinder & Co., Rights pending — permission not yet requested. Web page (watchfinder.com)
Hamilton 992B railroad pocket watch exterior with Ferguson-style dial
Hamilton 992B railroad pocket watch exterior with Ferguson-style dial — Jack Stephens, Rights pending — permission not yet requested. Web page (watchfinder.com)

Photographs are illustrative examples of the type, not necessarily the exact object described. Verify details against the source file page.

Sources & references

  1. Hamilton Watch Company service literature
  2. NAWCC Bulletin

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