The Phillips Head M3 X 13mm Self Tapping Screw (Pack of 100) tip should be snugly seated in the screw head. If it's too tiny, it might damage the screw head and make it hard to drive. Phillips-head screws should never be driven with slotted-head drivers. You'll ruin both the screw and the driver. The Phillips head screwdriver was created and patented by Henry Phillips in the 1930s and was originally used on the 1936 Cadillac. The great thing about it is that unlike the flat head screw (with a single ridge at its tip to slide into a screw with one slot), the Phillips screwdriver is self-centering. Its "X" design won't slip out of the X-slotted screw. Instead, it grips the screw firmly in the center, provided it's the suitable size for the screw.