Lag Screws are heavy duty fasteners used to connect heavy lumber or other materials that bear a strenuous load. They are manufactured from low carbon steel and can be used with lag shields in a variety of masonry applications, such as concrete, brick, and mortar. Lag Screws can also be used where standard wood screws are too short or small. In some applications, a pilot hole may be pre-drilled to prevent splitting or snapping. ASME B18.2.1 cover the requirements for steel lag screws.