Bryan:
To add to the fine information posted by pocwatjim, the serial numbers of 16-size Hamiltons jump from 900,000 to 1,000,001 (with 18-size watch serial numbers in-between), so the fact that the 950 was fitted with a four-foot dial up to 1,020,000 wasn't that much of a stretch. In fact, 856,000 was the last 950 built until 1,020,001 was made. In actual years, the difference was the change of the year from 1913 (856,000) to 1914 (1,020,001).
As noted above, Hamilton's pocket watch serial numbers weren't assigned in strict chronological order. Instead, huge blocks were allocated by watch size. If you check the various published serial number lists,
Serial Number 1 - 194,000
Serial Number 194,001 - 501,000
Serial Number 501,001 - 923,000
Serial Number 923,001 - 1,513,600
Serial Number 1,513,601 - 4,523,000 & Letter Prefix Serial Numbers
you'll find the following:
- - - - - -1 - - - - 49,950 18-size
- - 49,951 - - - - 50,000 Unknown
- - 50,001 - - - -85,000 16-size
- - 85,001 - - - 300,000 All 18-size (except HWW models)
- 300,001 - - - 400,000 All 16-size
- 400,001 - - --700,000 All 18-size (except Ball models)
- 700,001 - - - 900,000 All 16-size
- 900,001 - 1,000,000 All 18-size
1,000,001 - 1,400,000 All 16-size
1,400,001 - 1,450,500 All 18-size
1,450,501 - 1,500,000 Unknown
1,500,001 - 1,750,000 All 16-size
1,750,001 - 2,300,000 12-size & Other
2,300,001 - 2,655,300 All 16-size (2,655,301 - 2,900,000 not shown)
It's a fairly safe bet that 100,000, 200,000, 300,000 or 400,000 of one size watch weren't made before making similar numbers of another size of watch. Examination of the Hamilton production ledgers shows that within runs of a grade, there can be several years of variation. Just to demonstrate how difficult it is to come up with an accurate production date based upon a serial number range, this
Scan From A Hamilton Production Ledger Page shows that the 992s within the tiny range of 786001-786020 were finished and sold almost two years apart. Thus, attempts to use serial number vs. date lists (created by using the average number of watches produced over a period of years) as anything other than gross indicators of date of production are flawed to a greater or lesser extent. In general, we think of serial number lists (not just for Hamilton, but for other watch manufacturers as well) to only be accurate within a year or two at best, and recognize that there are numerous exceptions wherein which the dates may be off as much as 3 years or more.
