When looking for the number on your watch you should be looking at the serial number on the movement, not the case.
Click here to view additional historical photos of the Waltham factory.
Their revolutionary business plan was to manufacture the movement parts of watches so precisely that they would become fully interchangeable.
Based upon the experience of earlier failed trials, Howard and Dennison eventually perfected and patented their precision watch making machines, creating what has been called the American System of Watch Manufacturing.
Don't throw your Waltham watch away though as many people will buy it from you to use as spare parts.
As you can imagine there are a lot of Waltham pocket watches and those that repair them or various collectors are always on the look out for real parts.
The Waltham Watch Company, also known as the American Waltham Watch Co.