Lag screw sizes, also known as lag bolts or coach screws, are used in construction applications when a greater amount of load is required. They differ from normal wood, self-drilling or sheet metal screws because they have coarse threads and require a hole to be drilled before installation. The size of the hole is important as a lag screw must be able to bind to the material being fastened in order to support the additional load. Lag screws are available in a variety of lengths and diameters to accommodate any project.
Lag screws are made from a variety of materials including steel, zinc, and hot-dip galvanized. They are available in either hex or square head varieties. They can be installed using a ratchet, socket wrench or power drill with the right driver bit.
Typically, larger-diameter lag screws will not feature a full point and instead have a semi-cone or gimlet point. This is because it would require too much torque to screw a large screw into material without a pilot hole first.
In addition to indicating the root diameter, the lag screw sizing chart provides a range of other measurements to help users select the right fastener for their application. This includes the head height across flats and corners as well as the head width across corner angles. The sizing chart also notes the minimum and maximum thread dimensions and identifies whether or not the screw has a reduced diameter body. This is useful to know because a reduced diameter body screw will have a shorter unthreaded section than the root of the screw. Lag screw sizes