When it comes to construction, there are a lot of different types of bolts and screws for fastening materials together. But one of the most common types of fasteners, and one of the strongest, is a lag bolt. Also known as a hex lag screw, lag bolts are essentially heavy-duty wood screws with a hexagonal head that allows for higher wrench installation tension.
They are most commonly used for carpentry projects that require strong connections between materials, such as decks and outdoor structures like sheds or playhouses. However, a lag bolt can be useful in just about any type of project that requires fastening two materials together, including furniture repair projects and automotive repairs (such as securing body panels).
In terms of sizing, a general rule of thumb is that the lag bolt should be roughly twice the thickness of the material you are attaching to it. The longer the lag bolt is, the more it can support because it will penetrate deeper into the material, and the strength of a lag bolt also increases as the length of the bolt increases.
To determine the correct lag bolt size, start by clamping together the two pieces of material you want to screw together and measuring their width. Then, select a lag bolt that is at least 1/4 inch shorter than the accumulated width of the two pieces.
Before starting to install the lag bolt, make sure that you have all of the necessary tools on hand. You will need a drill that can be fitted with a spade drill bit to create countersink holes for the bolt heads. You will also need a socket wrench with a ratchet attachment to tighten the bolts. Lag Bolt