Lag Bolt Pilot Hole Size
One of the most common errors made when installing lag bolts is drilling the wrong sized hole. This can lead to the bolt becoming loose and potentially causing damage to the structure. Using the right drill bit will help to prevent this from occurring, and can make the entire process of installing lag bolts much easier.

Generally, the lag bolt should penetrate at least 1.5 times its own thickness into the material it is being attached to. This will ensure that the bolt will have sufficient strength to provide a secure hold. Depending on the application, however, the actual penetration required may vary.

When selecting the proper drill bit size for a lag bolt, it is important to consider the wood type and thickness that is being used. Different species of lumber have different densities, which affect the ideal bolt shear values in each particular wood. For this reason, it is recommended that you perform some experimentation in your own projects to determine the correct drill bit sizes for specific wood types and applications.

A general rule of thumb for selecting the proper drill bit size for a particular lag bolt is that the drill bit should be the same size as the bolt’s core (without the threads). This can be determined quickly by simply placing the lag bolt in your palm, then placing a drill bit next to it. If they match, the drill bit is the appropriate size for the lag bolt. pilot hole for 3/8 lag screw