One year later, Mr. Anderson filed for another patent (#559,763) for a “tool for expanding ends of lead pipes”. This patent refers to the tool shown here. The description specifically mentions that this tool was to be used in conjunction with the previous earlier patent. Of particular note is the mechanical method of expanding the conical jaws in an even and controlled manner; this ensured the resulting expanded part retained some concentricity. It is also assumed that this tool was used in opening up an inlet in risers for joining dissimilar-sized pipes. The pipe expander has a unique mechanical advantage in that as the jaws are opened, they remain parallel; all that is required to create or enlarge a smaller opening in the lead medium is the insertion and full rotation. This method works due to lead’s extreme malleability.
Allegedly, Stanley Tools produced this tool; however, some examples have only the patent date imprinted on the tool, with no clear manufacturer’s name to be found. This pair is conspicuously marked with the patent date and the brand, “Wm Johnson Newark, N.J.”, which was a large, heavy-hardware retailer, circa 1905 to 1910.