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What's the mean for 3992B out circle dial? "Click" to Login or Register 
The hamilton 3992B has three circle mark. the out circle is from 1 to 10, how to use it and what's the mean? thanks for help.

Posts: 53 | Location: Chong Qing in China | Registered: August 27, 2011
Photos are very important to identification. A nice clear photo of the dial, another of the markings on the back, and a third of the movement are needed.

Until you post these photos, is this what you have? If so it is a post WW2 repurposed watch. The three concentric chapter dial was installed during the repurposing to meet requirements of NATO since the UK and Commonwealth at that time were coordinating their militaries with NATO. On these rebuilt 3992B watches they were made with an outer chapter going from 1 to 10 with 10 hash marks between each number being for the purpose of being able to divide each minute into 100 parts. This allows for measuring a minute in a decimal fashion with each hash mark being 1/100th of a minute and each number being 1/10th of a minute. The middle chapter is the traditional 60 minutes markings and the inner chapter being for the traditional 12 hours. NATO wanted these remanufactured watches to have the 1/100th of a minute divisions to make for easier calculations of various kinds when using the metric system on which NATO was standardized.

Posts: 869 | Location: Baltimore, Maryland USA | Registered: September 20, 2004
Administrative Assistant
Picture of Dr. Debbie Irvine

Thanks Jim.

Posts: 5181 | Location: Northern Ohio in the U.S.A. | Registered: December 04, 2002
Thanks Jim.

That's the correct picture you posted.
Posts: 53 | Location: Chong Qing in China | Registered: August 27, 2011
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