1945 1B1101-1B4000 1945 - 1947 1B4001-1B8208 Dec 31,1948 1B23,500 1953 1B27,500 1954 1B27,501 and higher, till end of production in the mid '60's.
All 992B had a serial number starting with C All 2974B had a serial number starting with K, or 2K, total production in excess of 16,095... 2974B production at the end of WWII was 15,5B had a serial number starting with 3C, total production of 2497 or maybe a little more... 4992B production at the end of WWII was about 95,000 more were made during the cold war,and even 'Nam.
Hamilton Watch was founded by merging Keystone with the Aurora (Illinois) Watch Company. The name Elinvar was derived from the term "Elasticity Invariable" and was the first alloy to resist the changes in elasticity that occur with changes in temperature.
3992B production was from 1943 to19B had a serial number starting with 4C, total production of 142,000 and higher.. The myth about the "Officer's Model" 4992B in the Coin Silver Case, is just that, a Myth. All 4992Bs in silver cases should have serial numbers from "43 ...
in April 1943 the spec's were changed to allow the use of a "non-critical" alloy, in order to conserve Nickel, the major component of "Base Metal".
Its founders possessed a good combination of skills: Mr. Like so many infant industries, Adams and Perry did not have enough capital to market their product. During World War II, Hamilton ramped-up production of several models of chronometer to meet the US Armed Forces (particularly the US Navy's) need for an extremely accurate timepiece which could be used for navigation at sea.
Lancaster citizens came to their rescue in 1877, raising 5,000, and the reorganized company was renamed the Lancaster Watch Company. Prior to WWII, such highly accurate instruments were only produced abroad.