What is really informative is the list of the patents, by tool marking indexed to the tool company
For example :
Myers, C.H. Patent 288,098
in the A-M section of http://home.comcast.net/~alloy-artifacts/site-index.html
Now if you are looking up a wrench that says "model 1226" you click on the "Model 1226" and it then links you to a photo of the wrench and gives info about it.
If you are looking up (Plvmb or Plomb) another source that has a really fast easy guide to what year it was made is http://www.vannattabros.com/plomb/plombtool.html