Screws come in a wide range of sizes for an endless number of projects and repairs, but selecting the wrong one can lead to a poor connection or even damage the material. To avoid these issues, accurate measurements are essential. This article explains the three main types of screw measurements, including gauge, length, and thread pitch, so you can select the right size for your project.
Gauge is the first measurement on a screw’s packaging, and it refers to its overall diameter. For imperial screws, this is typically indicated by a number that corresponds with a fraction of an inch; for example, a #8 screw has a diameter of 1/8″. For metric screws, you can use a thread gauge to find out the length and diameter; these tools usually consist of numerous strips of metal with various sizes of thread cut into them, which you can systematically work through until you find a match.
Length is another important metric to consider; a screw that’s too short won’t be able to hold two materials together, while a screw that’s too long can poke through the pieces, creating a safety hazard or an unattractive look. In addition, you’ll also want to consider whether the screw will have a flat head or a torx head; a flat head sits flush with the surface of the material and requires a countersink during installation, while torx screws feature six-point stars on their heads for better torque transmission and less risk of stripping. 1/4 lag screw pilot hole