Unlike standard screws, Lag Bolts (also known as lag screws) require a larger pilot hole size to ensure proper installation and that the bolts will hold. They are designed to penetrate and thread into two pieces of wood and can withstand much higher tensile and shear strengths than standard screws.

Pilot holes, also referred to as lead holes, are used in woodworking for a number of reasons, including to ease the installation of large diameter lag bolts. Unless specified, all our lag bolts are produced with a semi-cone point rather than the gimlet point typically supplied on smaller import products. This helps to prevent the heads from breaking when the lag bolts are tightened.

To determine the correct pilot hole size, first calculate the combined width of the two pieces that you are connecting. Then, select a lag screw that is 1/4 inch shorter than the aggregate width of the pieces. Next, use a drill bit that is the same size as the lag screw’s root diameter (the unthreaded portion) to make your pilot hole.

Then, a screwdriver can be used to insert the lag screw. If you are using a large lag bolt for heavy loads or in wood that has been treated with chemical preservatives, it may be recommended to use a lag screw with a larger head and/or longer length to improve its strength.

If you’re a homeowner or contractor working on major construction projects, it’s important to understand why you need to pre-drill pilot holes for lag bolts and how to correctly do so. By ensuring the right pilot holes are made, you can quickly install lag bolts and get back to work. pilot hole for 3/8 lag screw