Instructions
Locate the name of the manufacturer on the Stillson wrench itself, usually near the head or handle. If the company is still in business, browse the company̵7;s product catalog to see if the wrench is still in production. If the company is no longer in business, research the company̵7;s years of operation to narrow down the wrench̵7;s age.
Locate the patent date at the top of the Stillson wrench near the company name. This date will help approximate the age of the wrench by showing the year the device was patented.
Locate a five- to seven-digit patent number at the top of the wrench. Cross-reference the patent number using the U.S. Patent and Trademark Office̵7;s patent database. In most cases, this will produce a patent date that can be used to determine the wrench̵7;s age.
Consult an antiques dealer or a historian specializing in antique tools. The antiques dealer or historian may be able to determine the approximate age of the wrench by using clues that are left unnoticed by untrained eyes.