Gruen Wadsworth Case Serial Numbers

Updated November 2015

Dating A Gruen Wristwatch from a Wadsworth Case Serial Number

I'm grateful that I can share with you MORE tools for your Gruen toolbelt. Another wrench (spanner for you Brits) in the toolbox is always welcomed as Gruen collectors need all the help they can get.

There are two different case dating methods for Gruen wristwatch cases that were manufactured by Wadsworth. One was developed by Jack Wood, the other Barry Cooper. Both are top-notch Gruen historians and researchers.

These techniques involve looking up a portion of the Wadsworth case serial number in a table to determine the date a Gruen case was manufactured. While these tables appear simple, like all Gruen research work, considerable effort was expended by these individuals to create them.

Before presenting the tables and techniques, a word about case dating....

The Wadsworth case date is the date the watch's case was manufactured.  If you want to know the exact age of your watch, then this date is what you are seeking. Let's call this date, the date your Wadsworth case was made, the Wadsworth Date. 

If you are attempting to identify your watch, that is, you are seeking the model name and other detailed information about it, then you are actually looking for a different date. For identification research, the critical date is the "Introduction Date", the date the watch model was first introduced to the public for sale. The reason for this is simple; you are most likely to find the most information published about a watch when it first went up for sale. Advertisements and catalogs, the primary source of your identification data, will contain the newest models, not those that have been shipping for 4 or 5 years.

Your Wadsworth Date will be later than the Introduction Date. You will want to look further into the past when searching for detailed data about your watch. More about this can be found in the ID You Gruen! tutorial.

Technique 1 - Serial Numbers that begin with the letter G or L

Jack Wood's article that described how his technique for determining the date a Wadsworth case was made was published in the Sept/Oct 2012 NAWCC journal. Click "Dating a Gruen Wristwatch from a Wadsworth Case Serial Number" to download a PDF copy of the article.

For this particular dating technique, two criteria must be met. 

1 - The case must be manufactured by Wadsworth
2 - The case serial number must start with the letter G or letter L

If both of these criteria are not met, then this technique will not work for you. 

If your case is a Wadsworth case, and you find a 5 instead of a Gx or Lx at the beginning of the serial number, then you may be able to use the Cooper tables... see Technique 2 below.

See Figure 1 below for how to read a case's serial number that has a G or L prefix.

Technique 2 - Serial Numbers that begin with the number 5

This technique was developed by Barry Cooper, co-author of the Style Number dating paper. His most recent Gruen article was on Tanks and can be found in the members on the NAWCC NAWCC website.

If you're Wadsworth Serial Number didn't have a letter G or L at the beginning, but instead has a 5, then you're in luck! You MAY still be able to find the date the case was made, if it was made between 1925 and 1930.

The first 2 digits of the serial number are used to look up the date in Table 2 below.

Prefix Code       Year

50                     1925
51                     1926
52                     1927
52                     1928
53                     1929
54                     1930

Table 2 - Wadsworth serial numbers 1925-1930

This technique provides a date with an accuracy that is +/- 1 or 2 years. 

Like so many of the Gruen tools, it is not perfect, has some amount of error, but it works most of the time. In the grand scheme of things, these error amount are miniscule. If you can narrow your watch's date down to a year or two, then you're doing great and likely know a lot more than when you started.