Going Nuts: Metric Nuts at Mr. Metric
No provider of metric fasteners would be complete without a full line of metric nuts, and at Mr. Metric we have more nuts stored away than a squirrel at wintertime. But what do all these different nuts do, and which type or types do you need to purchase? Let’s take a glimpse at the world of nuts.
The essential purpose of any nut is to mate with a bolt to discourage the bolt from loosening its grip against a surface. When you thread a nut onto a bolt until it sits tight against the opposite side of the surface from the bolt head, you create a kind of stress on the threads called preload that holds both parts in position. Nuts come in a wide range of sizes and shapes, though the trusty six-sided hex nut is probably most well known. Some nuts have shapes that allow for protruding bolt heads, such as the acorn nut with its hollow cap-shaped head. Wing nuts have wing-shaped handles for easy tightening by hand. Sometimes the shape of the bolt determines the shape of a nut. If you’re using a square bolt, for instance, you’d want a square nut.
Vibration can eventually loosen a bolt even if that bolt is secured by a nut. How can you forestall this problem if your structure will face constant vibration during its working life? Well, you can always place a second nut innermost to the surface. This nut receives about 50 percent of the torque of the outermost nut, which receives full torque. Another solution involves the use of a locking nut. Locking nuts have internal or external teeth that bite into the surface for extra grip.