You will need two pieces of information to determine the date of your American-made, antique pocket watch: the name of the manufacturer and the serial number on the watch’s movement.
The manufacturer’s name may be very simple to find, or it may require some deeper investigation. If the major components of the watch (the dial, the case, and the inner workings) were all made by one company, you should find the same name marked in all three places. Easy enough! However, in many instances these three locations may each be marked with a different name. Prior to the 1920s cases were usually made by one company, while the watch works were made by someone else. If you find different names marked throughout the piece, the one that really matters is the one on the movement.
In order to get at the movement you will need to open up the watch case. First, begin by looking your watch over carefully. Note the location of any hinges, notches, or
areas that look like they were made to be pried open. The method for getting at the movement will vary depending on how the case is made.
Some watches open with a hinge near the six o’clock position. Often there is a raised lip opposite the hinge that you can pry open with a finger nail or pocket knife.
Another common construction is the hunter’s case. Here you have two hinged covers: one for the front and one for the back of the watch. These watches open by pressing down on the crown of the watch to release a tiny latch. Do not try to pry this type of case open.
A final option is the bezel construction, which means there are no hinges or notches for prying. The case is threaded so that you can unscrew the back of the case and remove it completely. Hold the watch face down in the palm of one hand, and then press the palm of your other hand firmly against the back of the case and rotate it counterclockwise.
Once you have opened the case, look over the inner workings of your watch. You should find a serial number marked on the movement. Remember you must use the number on the movement, not the numbers on the case, to date your watch.
With the maker’s name and the serial number from the movement, you can look up an approximate production date for your watch using the Serial Number Production Date Tables found here. This site also includes links to helpful discussion boards where you can find expert help if you are really stumped.