Lag bolts, sometimes referred to as lag screws, are some of the toughest fasteners on the market. They’re used to fasten into heavy lumber and other materials that need to withstand intense forces. Because of this, they have a superior load-bearing capacity and shear strength when compared to other types of fasteners like wood screws or self-drilling screws.
Technically speaking, lags should be called screws rather than bolts because they are not assembled with a nut and are installed by turning the head of the fastener. However, since lags have the characteristics of both bolts and screws, it’s not uncommon to use the terms interchangeably when discussing these heavy-duty fasteners.
When using lags, it’s important to make sure you have the right tools for the job. Typically, you will need a drill with a socket attachment to properly tighten the fastener, as well as a spade drill bit that can create countersink holes for the hex or square head of the lag. Having the right tooling will help you achieve a hassle-free, fastener that will last for a long time.
In addition to the basic drilling and hex-head driving requirements, you should also be prepared to use washers with your lags whenever possible. Washers increase the surface area that contacts the application material, which helps reduce the chance of a hex head digging into the wood and causing damage or cracking. These washers will also help ensure your lags are properly secured to the application surface and prevent them from loosening or falling out. lag bolt