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The Encyclopedia of Horology

Research tool

Serial Number Research Centre

This tool never guesses a date for a number you type in. Instead, pick a manufacturer and a number type below to get the documented research route for that maker: where the number lives, what it can genuinely tell you, which published sources or archive services to consult, and how confident that kind of estimate is allowed to be.

Important limitation

What this tool will not do

There is no field here to type in a number and receive a manufacturing date. Publicly circulated serial charts are frequently incomplete, community-reconstructed, or (for some makers) not officially endorsed at all. Entering a number and being told a confident date would misrepresent the actual state of the evidence. Instead, use the selectors below to see how that maker's numbers should be researched, then consult the cited sources or official archive service yourself.

Step 1 & 2

Choose a manufacturer and a number type

Research route

American Waltham Watch Company — Serial number

Dating confidence for this maker:Partially verified

General guidance for this number type

A maker-assigned sequential (or, in some modern cases, randomised) identifier, most often stamped on the movement but occasionally elsewhere depending on the manufacturer.

Typically found: Commonly the movement top plate; on some makes, the case back or rehaut instead.

Research note: A serial number is only as useful as the documented table behind it. Confirm which component actually carries the number before consulting any dating table, since 'serial number' is used loosely in the trade for movement, case, or (rarely) dial numbers alike.

American Waltham Watch Company — what is actually documented

Archive / published sources
The NAWCC and several independent enthusiast sites publish serial-number-to-year tables compiled from factory production records; the Pocket Watch Database (pocketwatchdatabase.com) is a commonly cited public lookup, though it is a community-maintained resource, not a facsimile of a Waltham factory ledger.
What the numbers mean
Waltham movement serial numbers are generally sequential across the company's production and can be mapped to an approximate year of manufacture using published tables.
Movement vs. case numbers
The serial number on the movement (usually on the top plate) is the only number with a documented dating table. Case numbers are a separate, case-manufacturer-specific sequence (Waltham used both in-house and outside casemakers) and do not date the movement.
Dating confidence
Estimated, not exact: published tables typically give a year in which a batch of serial numbers was assigned, not the day a specific watch was cased and sold, which could be considerably later.

Do not conclude

  • Do not assume the case and movement are original to each other just because both are old — verify hallmark/case-number consistency separately.
  • Do not treat the serial-derived year as a sale date or an assembly date; it is a manufacturing-batch estimate.
  • Do not assume a 'grade' name printed on the movement is a precise indicator of specification without checking it against the corresponding published grade table.

Record status

Manufacturer
American Waltham Watch Company
Number type selected
Serial number
Confidence classification
Partially verified

Sources & references

  1. NAWCC published serial number resources
  2. Community-maintained Waltham serial lookup tables (treat as a starting point, not an authoritative primary record)

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

Confidence classification

How confidence labels are used throughout this archive

Verified

Obtained directly from a manufacturer's own archive service or an unambiguous primary record for that specific object.

Estimated / partially verified

Derived from published tables reconstructed from surviving or partial records; useful for an approximate era, not a precise date.

Community-contributed

Compiled by collectors and enthusiast communities from observed examples, not from a released factory ledger; treat as a starting point only.