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Square-Headed Screw - Invented by P. L. Robertson

P. L. Robertson-Square-Headed Screw
: 1908
: Canada
: Power & Hand Tools

About Invention

In 1908, square-drive screws were invented by Canadian P. L. Robertson. Twenty-eight years before Henry Phillips patented his Phillips head screws, which are also square-drive screws.The Robertson screw is considered the "first recess-drive type fastener practical for production usage." The design became a North American standard, as published in the sixth edition of Industrial Fasteners Institute Metric and Inch Standards. A square-drive head on a screw can be better than a slot head because the screwdriver will not slip out of the screw's head during installation. 

The Model T car made by the Ford Motor Company (one of Robertson's first customers) used over seven hundred Robertson screws.


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