I've seen a couple of these U.S.M. ..adjustable "S" wrenches -- the ones I've seen were drop forged. United Shoe Machinery was formed by merging all the shoe manufacture related machinery makers & eventually held a monopoly. Although headquartered in Boston, the company had operations in several locations & also was incorporated in New Jersey. I have not been able to verify that they owned a tool making operation in Newark, but they certainly were big enough to have done so.