What is a Robertson Screw or Robertson Head Screw?
Most of us call Robertson screws “square drive” or “socket head” screws. They were invented by Canadian traveling salesman Peter Robertson around 1906. Up until that time, almost all screws were “straight drive” or “slot head” screws. Robertson’s screws were superior to slot head screws since the square recess automatically centered the screwdriver, provided more surface area for the driver to press against and reduced the chance of slippage.
According to legend, Henry Ford discovered using Robertson head screws could shave almost 2 hours off the assembly time of a vehicle. But since Robertson refused to sell exclusive rights to the robertson head screw to Ford, he turned to use a screw developed by a guy named—you guessed it—Phillips.