I would like to know the defference between the 992 and 992B hamilton's what made the 992B better than the 992

Materials such as Elinvar balance springs, white steel mainsprings, and solid balance wheels are reported to be the main difference.

While these do spell some "difference" in the anticipated quality of timekeeping, the quality of FINISH of the movements did (in my humble opinion) deteriorate significantly. The one on the right is a 992B

Thanks David for the info what one did you think keep better time of the two when they came out of the factory brand new and were a better made watch.

I would have to agree Dave, the 992 is a much more beautiful finish and would require a great deal more time to put the demakeening on. I would have to assume that the bridge plates would all have to be installed onto the pillar plate and done at the same time before any assembly work could even begin. What a gorgeous timepiece that 992.

Steve

the 992 probably had more "craftsmanship" involved in its manufacture but the 992b was a much improved watch being adjusted to six positions rather than five, have the proprietary elinvar extra hairspring, invar balance, press fit jewel settings rather tan screwed jewel settings among others. Some of these changes were to ease manufacture but some made for a clearly better time keeping mechanism. The 992b and its big brother 950b are generally considered to be the best railroad grade watches made.

In the 1940s when the 992B was introduced it was a big improvement in design that kept up with modern technology. Hamilton went in to watch manufacturing in 1893 specifically targeting the railroad market. They advertised themselves as "The Railroad Timekeeper of America" and "The Watch of Railroad Accuracy" and said "The Fastest Trains in America run on Hamilton Watch time". We see their highly successful 21 jeweled 18 size Grade 940 on the flags of a vintage slide valved steam locomotive of the 1890s, time marches on and the new Grade 992 adorns the smoke box of a more modern cylinder valved locomotive of 1917 at the head end high-speed passenger train. The grade 992 evolued into four models improving along the way, as the railway industry did. While steam locomotives were not a problem, the modern electric locomotives of the Pennsylvania Railroad, and the Chicago Milwaukee St. Paul and Pacific did raise concerns. Hamilton aware of this problem came up with the 992E and its anti-magnetic Elinvar hairspring in the 1930s. The biggest change was yet to come, and that of course was a diesel electric locomotive that changed the railroad landscape of the world during the 1940s and 1950s. Hamilton once again was the leader in the field with the introduction of the 992B that became the last American railroad pocket watch manufactured in 1969. I quote Colonel George Townsend from his 1977 book Railroad Pocket Watches "The Hamilton railroad watches enjoyed the most popularity with the railroad man. It is still being used today by my more railroad men than any other pocket watch."

"992 on smoke box from cover of 1917 time book"

"The Fastest Trains in America"

Who knows what would have happened if Hamilton had developed the tuning fork concept for the electric wrist watch instead of the magnet driven balance principle, they might still have been in business today and being used by the railway men of North America.

Photo taken by me, carrying my 992B firing diesel electric driven passenger train No. 2 The Canadian at Gleichen, Alberta December 1979.

Larry, you answered the question best of all, the non-magnetic components made all the difference needed to keep things "on time" in the much more active magnetic influences of life from the late 1930's on.

I have worked on "dresser drawer" watches that were so heavily magnetized that the balance spring actually tries to "stick" to the balance wheel cross arms.

Also, the higher productivities of gang-drilling, press jeweling etc., would significantly help meet the demand of the war. But I would bet money there was just as much work involved in finishing the movements to the accuracies expected of RR watches (as opposed to bomb fuzes). The "6th position" pendant down adjustment which sounded "good" was almost a given. The "mean time error" was hardly modified by that "position".