Determining Size of a Pocket Watch

[srscherr]

I am new to Pocket Watch Collecting. How do you best determine the size of a pocket watch? One posting in 2002 states the best way is to lookup the serial number. Where do I go to look up the serial number that will indicate the size and date?

Can any one help me?

Regards,

Steve Scherr

[srscherr]

I am new to Pocket Watch Collecting. How do you best determine the size of a pocket watch? One posting in 2002 states the best way is to lookup the serial number. Where do I go to look up the serial number that will indicate the size and date?

Can any one help me?

Regards,

Steve Scherr

[Kent]

Hi Steve:

Welcome to the NAWCC Pocket Watch Message Board!

Like many of our other systems of measurement, American pocket watch movement and case sizes can be traced back to an English system, one known as the Lancashire gage. In this system, the size is based upon the diameter of the watch plate to which the dial is fastened, known as the pillar plate. 0-size has a pillar plate diameter of 1-5/30" (yeah, right!). Nominal sizes then increment by 1/30" for each count. Although there are exceptions, most American pocket watches, and Swiss pocket watches made for the North American market, are sized to even numbers with the most common being 0, 6, 12, 16 and 18. These account for the vast majority of American-made watches. A 6-size watch has a pillar plate diameter of 1-5/30" plus 6/30", or 1-11/30". The diameter of a 16-size movement's pillar plate is 1-21/30", and an 18-size watch is one whose pillar plate diameter is 1-23/30" ( 1-5/30" plus 16/30" and 18/30" respectively). For sizes below 0-size (written x/0), the 1/30” is subtracted from the 1-5/30. Thus a 6/0-size watch has a pillar plate diameter of 29/30”. This is right up there with 12 inches to a foot, 16 ounces to a pound and 32 ounces to a quart. The same people have brought us the term hundredweight, which isn’t a hundred of anything but it is equal to 8 stone. Since a stone is equal to 14 pounds, a hundredweight is equal to 112 pounds.

The fact that even sizes are almost always used, alleviating the necessity of making very fine distinctions, makes it easy to express the watch size with a fairly close approximation. First, measure the diameter of the dial to the nearest 1/32 of an inch, then subtract 1/32" and then subtract 1-5/32". For example, the dial diameter of a 16-size watch is 1-22/32". Subtracting 1/32", we get 1-21/32". Subtracting 1-5/32" leaves 16/32", Hence, its a 16-size watch. Remember to be careful of the hands when measuring the dial diameter. In order to measure the dial diameter, and only the dial diameter, don’t include any part of the case. The bezel, the metal ring that holds the crystal (glass), will have to be removed or opened. In the manner similar to the backs of watches, the bezel either hinges, snaps or unscrews open on an open-face watch and snaps off on a hunting-case watch. Refer to the essay on Opening Cases (http://www.knology.net/~ksinger/opencase.txt).

Also see What Size Is My Watch? (http://barrygoldberg.net/watchguide/size.htm) on Barry Goldberg’s website.

There are a number of references for looking up the serial number to determine size, grade and approximate date. Some are online, others are in books. The reference to use really depends upon the watch company.

Here are a few common ones online:

Waltham: NAWCC Information Storage (http://www.nawcc-info.org/WalthamDB/walsernum.htm) and choose Serial Number.

Elgin: Go to elginwatches.org/ (copy and paste in your web browser address field) and choose Elgin Databases.

Approximate date information for a number of makes can be found at PocketWatchSite (http://www.pocketwatchsite.com/walthamserials.html) and Oldwatch.com (http://www.oldwatch.com/info.html)

The best single reference book is: “Complete Price Guide to Watches, No 24,” C. Shugart, T. Engle and R. Gilbert, Cooksey Shugart Publications, Cleveland, TN, 2004 (a new edition comes out each year in February. This book is available at libraries, most major bookstores and online at the NAWCC Gift Shop (http://www.nawcc.org/giftshop/americart/bk_watch.htm) - edition No. 24 is pictured, but ask about edition No. 25).

Good luck,

[srscherr]

Thank you so much for the invaluable information. A tremendous help.

Regards,

Steve