What Is a Phillips Head Screwdriver?
The phillips head screwdriver (otherwise known as the "cross-head screwdriver") is one of the most common variety of screwdriver, and one of the most popular hardware tools today. It is recognizable by its cross or + shape, in contrast with the flat head of a typical screwdriver. Developed by John P. Thompson and Henry F. Phillips in the 1930s, the phillips head is substantially easier to use with electric and industrial tools, making it one of the dominant forms of the modern era.
In contrast with traditional straight screws, the phillips head is self-centering. With a manual screwdriver, this difference is incidental, but in an electric screwdriver, it enables far greater stability and control. It is also designed to cam out, meaning that once the screw as in as tight as it can go, the screwdriver naturally pops out. With conventional screws, camming out damages the screw and is to be avoided, but with the phillips head, it is a normal part of the screwing process. These two advantages are essential for electric screwdrivers, especially in industrial settings.
Later, the Phillips Company developed the Pozidriv for more specific mechanical use, and today the phillips head is common even on non-electric screwdrivers.