P. L. Robertson

Peter Lymburner Robertson was a Canadian inventor, industrialist, salesman, and philanthropist who popularized the square-socket drive for screws, often called the Robertson drive. Although a square-socket drive had been conceived decades before, it had never been developed into a commercial success because the design was difficult to manufacture. Robertson's efficient manufacturing technique using cold forming for the screw's head is what made the idea a commercial success. He produced his screws in his Milton, Ontario, factory starting in 1908. The brand has been sold over the years, and the manufacturing for the present corporation is done in Jiaxing, Zhejiang, China; but the Milton, Ontario, building was still a head office for a long time before moving to nearby Burlington, Ontario.