In 1933, Henry Phillips purchased the rights to a socket screw and redesigned it with a cruciform recess, creating the crosshead Phillips screw. Unlike slot screws, they were self-centering, meaning that the user did not need to simultaneously center the screw in its hole, steady the screwdriver or power tool, and then use the screwdriver or power tool to turn the screw all at once. Phillips filed several patents and soon formed the Phillips Screw Company. While he was initially met with resistance when trying to find manufacturers to make his Phillips screws, he persisted and was eventually able to convince the American Screw Company to take on the task. Then American Screw convinced General Motors to test the new Phillips screws on their assembly line. When GM used them to make their 1936 Cadillacs, they found that they helped speed production. Consequently, the Phillips screw was quickly adopted by other Detroit automakers. By 1940, 85% of screw manufacturing companies had secured a license from Phillips to produce the new screws. Today, Phillips screws are used to fasten countless items and are stocked in hardware stores all over the world.