A screw’s sizing is essential to its performance. A poor choice of a screw type and size can lead to stripped threads, improper connections, or even structural failure. Screws come in a variety of lengths, diameters and thread types to suit a range of applications and materials. The right fastener for the job can make all the difference in your construction project’s success. To choose the correct screw for your application, consider factors like the length of the fastener and its intended use (shear strength versus tensile strength), the weight that the screw may support, and the substrate material that it will be attached to.
How to Measure Screw Gauge
When shopping for screws, you’ll often see sizes listed in terms of their gauge and length, such as “#8 x 1-1/4″.” But what does this mean? The screw sizing system is complex and can be confusing to those unfamiliar with it. The first number is the screw gauge, which indicates the screw’s outer diameter and is measured in fractions of an inch. The second number is the screw’s thread pitch, which is the distance between each thread. The number is calculated by counting the number of thread peaks that are visible over a one-inch length.
Screws also have a number of other characteristics that can be important, such as head type and drive type. Screw heads can be slotted, Phillips, square, and hex and have various drive types to match different screw drives. 1/4 to mm