Screws come in a wide variety of sizes to accommodate different tasks, and knowing the differences between the many types can save DIYers time and frustration, as well as money. They can be classified by a number of characteristics, including head type and drive type. They can also be identified by their diameter and length, as well as screw head shape and countersink or non-countersunk design. They can be categorized by their thread type, too. Screw threads can be coarse or fine, and they are typically either unthreaded or threaded. They can also be referred to as unified or imperial threads, and the difference between them lies in how they are measured. Imperial screws are measured in inches, and gauge numbers are used to indicate the outside diameter of a screw’s threads. The smaller the gauge number, the smaller the screw diameter. Screws that are less than a quarter inch in diameter are labeled from #0 to #14. A decimal equivalent for each gauge is also listed on a chart, which can be found online.
The type of screw you need will depend on what task it is being used for, but a few common types include wood screws, finish screws and drywall screws. Drywall screws feature a curve on the junction of their heads and shafts, which prevents them from tearing when they are applied to drywall. Other features of this type of screw include coarse and fine threads and a flat or raised head. screw sizes