The lag bolt, also known as the lag screw, is one of the most rugged types of fasteners available. Used primarily to fasten into lumber, these extremely sturdy and durable fasteners can withstand enormous loads without failing.
Unlike other types of screws, such as wood and sheet metal screws which use UNC (national course) threads, the lag bolt uses coarser threads that are more similar to those found in bolts. The lag bolt is also thicker than other screws, with a large hex head. This makes it easy to install with a ratchet or a power drill and a right-angle drive bit.
Lag screws, sometimes called lag bolts, are often used for home projects such as building a deck or attaching a shed to the foundation. They’re also useful in construction and are commonly found in newer buildings, such as commercial and residential structures.
A basic nail hammered into a wood stud can support up to 20 pounds, but a lag bolt installed in the same hole has as much as nine times that capacity. The extra strength provided by the lag bolt comes from its larger shank size and its ability to grip tightly into wood and other materials.
When using lag bolts, it is important to first select the appropriate type of drill bit for the screw’s shank diameter. This will ensure the screw is drilled into the material correctly, with enough force to allow it to be tightened and secured with a wrench. Lag bolts are available in a variety of materials, including zinc-plated for moderate protection against corrosion and stainless steel 18-8, which offers superior strength and corrosion resistance. lag bolt