Whether it’s a home improvement project, an automotive repair or an industrial assembly, using the right screws is essential to ensure your work holds together properly and safely. Mistakes when it comes to screw sizing can have numerous consequences, from structural instability to wasted time and materials. This article will walk you through the basics of screw sizing and help you avoid costly mistakes.
Measuring a screw’s diameter is simple: All you need to do is measure the distance between the crest of one side’s threads and the crest of the other. This is known as the major diameter. Screw sizes are usually given a number and the thread count, which is the number of thread peaks within a one-inch length. A common screw size is 1/4 inch with 20 threads per inch. Screws with coarse threads are typically labeled UNC, while those with finer threads are referred to as UNF.
Once you’ve figured out the diameter and thread count, you can move on to measuring the head size and shaft size of your screws. Screw heads come in a variety of shapes and sizes, including flat, pan and dome-shaped. In general, a larger head provides more surface area, distributing pressure more evenly and increasing holding strength.
Shaft size, on the other hand, defines how far a screw will extend into the material. This measurement can be made with a ruler or tape measure, but calipers are ideal for more accurate measurements. screw sizes