If you’re a DIYer, it’s essential to know what screw size is appropriate for your next project. This will save you time at the hardware store and keep your screws from becoming snagged in their intended material. Screws are classified by their diameter (or gauge), threads per inch and shaft length in inches. Whether you’re looking for wood screws or fasteners for metal, knowing these specifications will help you select the right screws for the job.
Screw sizing can be confusing, especially when you’re working with different systems of measurement. While the imperial system is more common in the United States, metric measurements are growing in popularity around the world. The most important thing to remember when determining screw size is that it’s a combination of the gauge, number of threads per inch and shaft length. For example, a wood screw with a #10 diameter will have 32 threads per inch and a shaft that’s about an inch and a half long.
A screw’s type is also determined by the materials you’re trying to fasten together. For example, self-tapping screws are great for heavy-duty applications, such as roofing or structural framing. They have a hex washer and can come with neoprene washers to provide additional support for the fastening process. These screws are also available in a variety of materials and coatings to provide resistance to moisture, temperature changes and other environmental factors.
For lighter duty applications, you might choose a screw with a flat head that sits below the surface for a clean finish. For more heavy-duty projects, you can opt for a bugle or modified truss screw. These types have a flat top and concave bearing face that distributes stress over a larger area, making them ideal for attaching wood to metal studs.
You might also see the screw referred to as 12-24 or 12-24 rack screws. These types are used for racking equipment and are slightly larger and courser than 10-32 screws. They’re also available in a wide range of lengths, from 3/4-inch to 6-inch.
The most commonly used screws for home repair and woodworking are round head screws. These are suitable for general construction and woodworking, and can be driven in with either a Phillips or straight-edged screwdriver. They’re also a good choice for outdoor use, as they can resist corrosion from moisture and temperature fluctuations.
When choosing a screw, you’ll need to decide if you want it to be for indoor or outdoor use. Outdoor screws are typically silicon-coated to protect them from moisture and temperature changes. They’re also more expensive than indoor options, but you can find a wide array of finishes to match your design aesthetic.
Choosing the correct screw for your next project can be challenging, especially when you’re not sure what size drill bit to use. Thankfully, the diameter and threads per inch of a screw can be determined in a few easy steps. The easiest way to determine the screw size is by measuring the major diameter with a ruler or tape measure. Then, calculate the threads per inch by counting the number of threads in a one-inch section. #10 screw diameter