What Are Bolts, Nuts, and Washers?

Whether the assembly in question is as simple as a coffee table or a complex jumbo airliner, many structures require a number of fasteners to stay together and provide reliable load support. Fasteners in general are hardware components that are used to join together two or more parts either permanently or non-permanently. While there are a number of fasteners that are widely used across different assemblies, some of the most common and critical Fastener Types that cater towards many applications are bolts, nuts, and washers.

Bolts are a type of externally threaded fastener, meaning that they feature screw threads that wind down the shaft of the component. Alongside a Threaded Shaft, bolts also have a head that may come in various shapes to be tightened with specific tools when installed. Bolts are often compared to screws, due to their similarity in purpose and design. Despite this, bolts are set apart from screws in the fact that they are most often used to secure two or more unthreaded components together with the aid of nuts and washers. Screws, on the other hand, may form their own thread within the component that they are installed in as they are tightened. Bolts may be manufactured from a variety of materials, though the most common types are steel, stainless steel, bronze, and nylon.

Nuts are a fastener that feature a threaded hole, most often designed to mate with a correlating bolt for securing objects together. For installation, the bolt is passed through the component and the nut is tightened from the other side. Together, the components are secured in place with friction from threads, compression between the fasteners, and stretching of the bolt. The most common shape for a nut is a hexagon, mostly because it is able to provide for optimal torque and ease of tightening. Nevertheless, nuts may be in other shapes, such as early nuts which were square in design. Nuts are used in many applications alongside bolts, such as within automobiles, aircraft, furniture, and more. Depending on the need for nuts, various types such as a Nut Plain Extended or nut bearing may be used.

Washers are a component that may be used alongside a nut or fastener for distributing the load of the fastener, acting as a spacer, reducing vibration, serving as a wear pad, and much more. Often, washers will come in the form of a thin plate that has a central hole. With this hole, a bolt may be passed through Nuts and Washers to securely fasten an assembly while distributing loads. When components are in an assembly and are composed of differing materials, washers may be installed in between such components to prevent the effects of galvanic corrosion. Across the various types of washers, the most commonly used materials for manufacturing include steel, non ferrous metals, alloy, plastic, nylon, specialty materials, and phenolic. Common washer types include flat aircraft washers (washer flat aircraft) and spring tension washers (washer spring tension).