Dating waltham movements
The serial number will pinpoint the year of manufacture but not the exact date.Additionally, Waltham identified each pocket watch’s model name on the movement."The serial number is on the movement not the case".
Not all vintage watches can be dated using the serial number.Some American watch brands did not use a consistent series of serial numbers, but most of the big manufacturers did.Most vintage Swiss pocket watches did NOT have serial numbers and can't be dated by this method.The American Waltham Watch Company can trace its roots to 1849.Each timepiece has been engraved with a serial number since 1852, starting with number 50.
These are generally the easiest as for many makes, such as Waltham and Hamilton, production records are still extant and enthusiasts in the US have put a huge amount of effort into putting them into online databases so by taking the serial number of the movement (not the case number!