Glossary

A washer is a thin, typically disc-shaped component used in conjunction with bolts, screws, or nuts to distribute load, reduce friction, prevent loosening, or protect surfaces in heavy-duty applications such as construction, manufacturing, and machinery.

The flat surface under the head of a bolt or screw that directly contacts the clamped material. This surface is often machined or chamfered to help distribute the clamping load evenly, reduce wear on the material, and prevent the fastener from embedding or sinking into the installation surface.

A wave washer, also known as a wave spring, is a unique type of washer characterized by its wavy or curved shape. Unlike a flat washer, it's designed to function as a spring, providing a continuous force within an assembly. This spring-like action allows it to absorb shock, reduce vibration, and compensate for small variations in component dimensions or thermal expansion. Wave washers are particularly useful in applications where axial space is limited, such as in bearing preloading or taking up slack in an assembly to maintain a tight fit.

When a wave washer is compressed between two components, its wavy form flattens slightly, generating an elastic force that pushes back on the parts. This continuous pressure helps prevent components from loosening due to vibration and ensures a constant load is applied. They are an excellent solution for tasks like cushioning light loads and maintaining a secure connection in various industries, including automotive, aerospace, and electronics.

A wedge lock washer is a two-piece washer set designed to keep a bolted joint from loosening under vibration or dynamic loads. The washers are paired with cams on their mating faces and radial serrations on the outer faces. Installed cam-to-cam, the serrations bite into the nut/bolt head and the joint surface so nothing slips externally. If the bolt tries to rotate loose, the cams ride up each other; because the cam angle is greater than the thread pitch angle, the bolt must stretch to move—so preload increases and the joint resists loosening.

They’re reusable, work with lubricated or dry threads, and are common on machinery, vehicles, rail, and wind/energy equipment. For best results, use them as a pair only, cams facing each other, against hard, flat bearing surfaces (use a hard flat washer first on soft or painted materials). Variants exist for through holes and for countersunk screws.

A weld nut is a specialized type of nut designed to be permanently attached to another metal object, most often a metal sheet or plate, by welding. Unlike standard nuts, weld nuts have unique features such as flanges, locating bosses, or welding projections (small, raised points) on one face. These projections are engineered to melt during the welding process, creating a strong, permanent bond between the nut and the base material.

The primary purpose of a weld nut is to create a secure, high-strength threaded connection point on a surface where a tapped hole would be impossible or impractical, such as on thin sheet metal. Once welded, the nut becomes an integral part of the assembly, providing excellent resistance to torque, vibration, and loosening. This makes them ideal for heavy-duty applications in industries like automotive manufacturing, construction, and furniture production. Weld nuts are a type of "captive nut," meaning they are permanently integrated into the component, simplifying assembly by allowing a bolt to be fastened from a single side without needing a wrench to hold the nut in place.

A wheel bolt is a type of fastener used to secure a vehicle’s wheel to the hub. Instead of using separate studs and nuts, a wheel bolt threads directly into the wheel hub or brake drum/rotor assembly.

A wheel nut—also known as a lug nut—is a fastener used to secure a wheel to a vehicle's hub. It threads onto wheel studs and clamps the wheel tightly against the hub or brake drum/disc to keep the wheel in place during motion.

A chalky, white corrosion that forms on fasteners with zinc or cadmium-based metallic finishes, such as electroplated zinc or zinc-rich coatings. White rust indicates the surface finish has started to degrade, usually due to moisture or improper storage. This residue flakes off over time, exposing the underlying steel.

The distance measured between two opposite flat sides of a hexagonal (six-sided) fastener head or nut. This measurement determines the correct wrench size or socket needed to tighten or loosen a fastener.

Type A Wing Nuts offer two large metal wings that allow for easy hand tightening and loosening. They are designed to quickly assemble onto a stud, bolt, or screw and are commonly used in non-critical assemblies. Wing nuts are ideal for situations where a high amount of torque is not needed since the wings can be easily turned by hand. 

A wood screw is a type of threaded fastener specifically designed for wood. It creates a strong, lasting joint by cutting threads into the wood as it’s driven in, holding two or more pieces of wood together.

Also known as strain hardening, this phenomenon occurs when a metal becomes stronger and harder after being permanently shaped or deformed at room temperature. The mechanical force of shaping causes its internal structure to rearrange at a microscopic level, making it more resistant to further deformation. This natural increase in strength is a significant advantage in fastener manufacturing processes, such as cold forming and cold heading.