What is a Lag Bolt?
Lag bolts, also called lag screws, are large wood screws with hex heads for use with a wrench. They are used in a wide range of projects, both inside and outside the home. They are often galvanized for added corrosion resistance.
They are different from other fasteners like screws and nails, in that they require a preexisting hole of the correct size. Unlike other screws, a lag screw does not have a threaded shank, but instead has a pointed tip and wide-spaced threads that cut into and hold the wood. The holding power comes from the friction created by the threads as they bite into the wood fibers and pull them together.
A lag screw has as much as nine times more grip in wood than a nail, and can support much more weight. Lag screws are ideal for projects that require extra strength, such as a hanger for heavy items or a pulley to carry electric wire or twine.
It is important to take the proper precautions when using a lag bolt. This includes ensuring the proper head and shaft size, predrilling pilot holes where necessary, and tightening the bolt properly. If not installed correctly, a lag bolt could snap off inside the material and cause damage. Using the right tool is also vital. The best choice is a drill with a socket attachment and a ratcheting socket wrench. A spade drill bit is also helpful, as it creates the countersink holes required by lag bolts. Lag Bolt