The hex head lag screw is designed that way since hex headed fasteners are made to hold up in applications where a lot of torque is necessary. Lag screws have sharp lead thread points and are available in Steel/Zinc, Stainless Steel, and Steel/Hot Dip Galvanized.
TRADITIONAL VS. MODERN WOOD SCREWS Some of the differences between a traditional (lef t) and modern (right) wood screw are obvious. Modern screws offer more drive options (below) than traditional screws. Major thread diameter is larger than the shank diameter. Drives on modern wood screws are well suited for use with a drill driver.