Double Thread Self-Drilling Screws

Double-threaded screws have two sets of threads—one on either side of the screw shaft—which allow them to hold twice as much weight as single-threaded screws. The threads on each side run in opposite directions, creating a strong connection between the screw and the material it is being used to secure. Because of this increased strength and durability, these screws are perfect for applications where high amounts of weight will be placed on them.