Take a look at http://www.militarywatchmuseum.com/hamilton1.htm

The watch on the left is unmounted and the one on the right is mounted. You see the same thing in Robert Sweets' post earlier in this discussion.

You can see the unmounted version out of the box at http://www.oldwatch.com/Museum/hammod22front.htm

Don

The unmounted version of the Model 22 was discontinued fairly early in the 22 production as the favored version was gimbled. Reportedly, aviators liked the unmounted version since it was compact.

The unmounted (cased) Hamilton Model 22 was not discontinued early in the production of this watch but was in fact some of the last of the military type to be made. This chronometer was not used by aviators but was instead used as a portable chronometer to which master watches were set to. The US Navy was the last service to use these watches and they would have been used as before; as portable chronometers set to the ship's master boxed chronometers. That would have been taken around to the various departments that had master watches (aviation, communications plotting for example) needing to be set to the ship's master boxed chronometers. I have a very late (for military production) serial numbered Model 22 (cased/unmounted) that was aboard the USS Lexington. It was in the process of being calibrated right before the time the Lex was decommissioned and never made it back aboard. It is in a late 1945 marked case with CVA-16 engraved on the case back. The calibration sticker attached to the case back was dated June of 1991. When I look at the recorded serial numbers for this type, I see many more of the gimbaled types early on (1941, 1942) with more of the cased types coming into being during the later part of the type's run (1943). The civilian production finished off the run once the government no longer needed these watches and it looks like those are evenly split between cased and gimbaled.

Best,

James D.

Hope all is well in your AO James D. Most of my information that I used for the post above was taken from Marvin E. Whitney's book Military timepieces. Other information was taken from the Navy Yard Museum in Wash. D.C. The non-gimbled mounted Mod. 22 was withdrawn from service in 1948. The Gimbaled version remained in production for the civilian markets. I should clarify that the majority of both gimbled and non-gimbled watches were produced during WWII. By 1956, Hamilton produced a total of 28,773 Model 22 watches (9780 un-gimbled watches by the time they were discontinued in 1948). In 1956, 18,993 gimbled version Mod. 22's were manufactured. Although the Mod. 22 Un-gimbled chronometer was not designed to replace the aviation chronometer (4992B), it became popular for Naval Aviators to use them as they became available after 1948, and often prior to that year. (Navy Yard Museum, Wash. D.C.) Many of the un-gimbled 22's were sold to the U.S. Army Transportation Corps or used as "Special projects" or relinquished to the war surplus department. The engraving on the case's for the Army aquisition were altered to reflect the new owner, i.e. U.S. Army. I suppose to say that the un-gimbled was discontinued early might be a mis-statment if based upon production numbers being front loaded during the war years.

Below is the US Patent for the Hamilton Model 22 Chronometer Watch case dated July 4, 1944.

Due to the file size, below is a link to the patent description.

Patent Description

Robert

and a larger view....

Awesome. For general information, RCM watch Company of Lancaster, PA has advertised a wrist watch with a similar configuration in tribute to the Mod 22 un-mounted chronometer.