Screws may not be the most impressive or pretty things at a hardware store, but they play a vital role in just about any hobby or craft project. From wall framing to furniture-making, screws are the functional fasteners that hold it all together. It’s important for every handyman and DIYer to understand the different types of screws and their sizes. The more you know, the easier it will be to navigate the screw aisle at your local hardware store or online.
When looking at a screw, there are several things to consider: the head size and type, the shank, the threads and the tip. Each of these parts are characterized by their specific shape and function. For example, a screw’s head may be flat (pan head); round; or square (phillips head). The head shape of a screw will determine what driver you need to fit it. The shank is the smooth area between the head and the threads. It can be round, hex, or square and a number of different shapes in between. The threads are the ridges that wrap around the cylinder of the screw to create a helix. The tips of the threads are often sharp, which helps them bite into wood or other materials.
The way that a screw is measured depends on how it’s designed for use and the material it will be fastening. If a screw is designed for wood, it will be labeled with two distinct numbers: the gauge and the diameter. The higher the number, the larger the screw.
Wood screws come in a wide variety of sizes and are designed for different applications. For example, finish screws are designed for attaching trim and molding and have smaller heads than standard wood screws. They also have shorter shanks. Construction screws are a bit heavier-duty, and are often used to fasten things like hinges or light framing. Masonry screws are designed for brick applications and have longer threading than wood screws.
Screws are sized in either imperial or metric systems. The standard metric rack screw is called M6 x 1, where the ‘M’ stands for metric, the ‘6’ is the diameter in millimeters and the ‘1’ is the distance between adjacent threads in one inch, also in millimeters. The metric system is often used outside the US and has its own set of rules and terminology.
If a screw is labeled with a number that ends in zero, the diameter can be calculated by counting the extra ‘zeroes’ and multiplying by 0.013 inches and subtracting from 0.060 inches. For example, a #0000 screw has a major diameter of 3 x 0.013 inches and a pitch of 2 x 0.060 inches.
It’s also important to remember that a screw’s length is the distance from its head to its tip. This will help you figure out the correct length of screw you’ll need for your project. It’s easy to get confused when looking at the numbers on a screw, but it’s important to remember that a screw’s gauge is determined by its diameter, and its head size is separate from this measurement. #6 screw diameter