I just purchased a Hamilton 4992B U. S. Military Pocket Watch (22J, 16S) Ser# 4C137966, 24 Hour, marked on the dial GCT. I have been trying to find out more about this specific watch and the history of the 4992B. The watch came with a walnut case that appears to have made for the watch.

An excellent watch. The wooden transport cases are less common than the metal spring loaded types. Some images of your wooden case along with any markings on it would be appriciated.

If you run a search for the 4992B on this forum, you will find alot of information about these watches.

Find-Or-Search for 4992B

Best regards,
Greg

Thanks. I am posting several pictures of the case.

Inside cover

Inside base.

Case open

another

Steve,

Nice watch! It looks to be in near-mint condition. Can you post a picture of the back with the ordnance markings?

I have a 4992B with a close serial number 4C131485 which has the markings (see picture):

AN-5740-1
STOCK NO. 6645-663-7694
MFG'S. PART NO. 33106
CONTRACT NUMBER DA-36-038-ORD-20782(M)
SERIAL NO. AF-59-18156
HAMILTON WATCH COMPANY

I've always been curious if all 4992Bs had the same markings or if there were different ones for for the different branches of the military.

I found a reference that indicates 96,082 4992Bs were made from approximately 1941 to 1970. Some of the military watch experts will hopefully correct me if I have it wrong.

John III

I'd be interested in seeing the back of the watch as well AND the inside of the back cover.

I was told that the ones in the cases were usually .800 silver. I don't know if that was true of the wooden box or the metal box or both. I don't even know if it's true.

I have a .800 silver one in a wooden box but I'm certain that the box is a very nice aftermarket product.

I'm told that many of the aftermarket boxes have the maker's (forgot his name)signature under one of the hinges. But... here's an easier test. The platforms where the watch goes, on both covers, should have eight posts (each) holding them. These should be rubber or a similar substance. The platforms were designed to "give" a bit. Mine are brand-new looking and I suspect that any original boxes would have those pieces a bit dried and brittle... even if the watch was hardly used.

This pocket watch has no marking on the back of the case.

Here is the inside of the back cover.

Inside Cover

The box does have 8 attachments as you describe.

As of 1957 the total production for the 4992B 24 hour Master Navigational Watch was 119,739. The 3992B 12 hour Master Navigational Watch was 2,494.

During WWII, 2,000 watches were produced for the British Navy (mostly 3992B). 312 were produced for the Canadian Navy (I think they used the 12 hour versio as well). 73,285 were produced for the Army and 21,151 for the Navy. Most of the Navy models were in silver cases. They produced 7,726 Navigational Watch Boxes for the Navy. I get a total of 97,118 Master Navigational Watches produced for the Armed Forces during WWII. Small numbers were also produced for civilian use including for the major airlines.

You should know that the 4992B was also put into a round metal cannister. The watch was suspended by springs. I do not know when this system was being used and I do not know if it was commisioned by Hamilton or the government. I have never seen it discussed in Hamilton documents.

Most of these watches were used as a short term chronometer for airplane navigation. The hack feature allowed them to syncronize the watches to a standard time source in GMT. They would keep good enough time for navigation for the duration of a bombing raid. In celestial navigation an error of 4 seconds corresponds to as much error as one nautical mile in longitude. The error is greatest near the equator and less toward the poles.

Don

It is odd that your case has no military markings. The various militaries were pretty hard-nosed about making sure all of their timepieces were well marked since they were small and valuable and they didn't want them walking off. Does the Keystone case in which yours is mounted look original? Perhaps it is a replacement case, or perhaps it is a civilian version that was marketed to the public?

Everything appears original. Not sure why there is nothing on the back cover. everyones info has been very helpful.

thanks,

Steve

Perhaps it is a movement that was left over after the war that Hamilton cased and sold to the public?

I recently picked up a mint 4992B in the original box - check out the pictures...

Ordnance Markings:

AN5740
MFR'S PART NO. 4992B
SERIAL NO. AF42-23831
CONTRACT NO.
W535ac-28072
HAMILTON WATCH CO.

Movement serial no 4C60413 - absolutely factory new!

Original Box with matching serial number

I also picked up a new-in-box metal carrying case that is mentioned in the thread earlier.