The Pocket Watch Data Base pocketwatchdatabase.com shows letters after the numbers (eg. 999H) for Ball watches and I finally found something that helps explain it. []

Hamilton Ball Serial Numbers & Grade Descriptions

Excellent site, the watch collecting community learned of that site in January, 2010 (Google "999H Ball Hamilton" to find a link with some comments.) Independently, I had done similar work on the grades, but not in this depth reported. My published work of June 2010 was submitted late summer/early fall of 2009. At that time I had no clue what a 999A was and have always been grateful for this information.

In my opinion, these suggestions for that site might be worth mentioning.

Many of the 18-size movements that are today called 999A's & 999B's may not have left the Hamilton factory as Brotherhoods. For the most part they likely were originally ORRS and then after they left Hamilton were upgraded in-house by Ball Watch Company at their Cleveland, Ohio facility. Ball Watch company would have regarded this part of their finishing and completion process that also included casing and timing. The barrel bridges of those particular observed Brotherhoods usually have no serial numbers on their underside leading many collectors to conclude they were upgraded in the manner explained above.

The vast majority of these upgrades were performed by Ball to fill orders for Brotherhood Union members though some may have conceivably been done by later collectors to enhance the value of a particular watch. As with any premium or unusual watch it is absolutely imperative to have the CORRECT MATCHING DIAL on these and for that matter ALL the various grades of Ball Watches. It has often been said that with Ball Watches the proper dial is at least half the total value so consider that and avoid buying only half a watch. []

HAPPY HUNTING