Aviation Fastener Parts and Component Sourcing

Aircraft Fasteners Catalog

A fastener is a piece of hardware that secures or closes parts together, without creating a permanent joint like welding. Ropes and hinges can technically fall under this definition but are not called fasteners because of their various applications. Fasteners are specific items that form rigid, inflexible connections.

Fasteners are typically composed of steel (carbon, stainless, and alloy), aluminum, and titanium. They also often have coatings of black oxidizing, cadmium, zinc, chromium, silver, nickel, and cadmium to prevent corrosion and increase the lifespan of the fastener.

At NSN Parts Now, owned and operated by ASAP Semiconductor, we supply fasteners from some of the best manufacturers in the world, including Southco Inc, Arconic, Eaton, PCC Fasteners, and Monogram.

Traceability and Standards

Fasteners are used in almost every manufactured product, from military jets to children’s toys. However, the various types of fasteners differ in terms of quality and standards. High-stress and high-risk environments require higher standards for design, materials, composition, and safety standards. The automotive, marine, and aerospace industries all have higher standards for fasteners due to the demands of their operating environments.

Hardware components are commonly traded items. Because of this and their numerous uses, there are uniform standards placed upon them. The American Society of Mechanical Engineers (ASME) has instituted standards that define types of fasteners, along with their dimensions and the materials that should be used to produce them. The military also has its own set of standards that are applied to fasteners used its vehicles and equipment. Military standards require traceability, an important resource for guaranteeing safety and conformity.

Types

Fastener categories include bolts, buckles, clamps, clips, pins, flanges, grommets, latches, pegs, nuts, rivets, screws, studs, threaded fasteners, ties, washers, and zippers.

Drive types include: Phillips and Frearson, combination, socket, one way, square, and star.

Washer types include: flat, fender, split lock, internal tooth lock, dock, and ogee.

Nut types include: hex, nylon insert lock, jam, wing, flange, square, coupling, slotted, castle, and pin lock.

Anchoring products include: stud anchors, lag shields, machine screw anchors, double expansion sleeves, concrete screws, plastic toggle, self-drilling drywall anchors, hollow wall anchors, and anchor bolts.

Automotive Fasteners

The automotive industry uses many different types of fasteners, but the most common are bolts, nuts, and studs fastener. They vary primarily by minimum tensile strength and minimum yield strength. They are ranked on a graded system set by the Society of Automotive Engineers.

Automotive Bolts: Also called threaded fasteners, these components are used in high tensile applications that need a rigid, strong attachment. Bolts are headed, with a threaded blunt end. Compared to other fasteners, bolts have a longer grip length, and a shorter threaded portion for the attachment of a nut. Common bolts are U-bolts, hub bolts, and wheel bolts.

Automotive Nuts: Automotive nuts are square or hex shaped, with a threaded circle in the center. They are used to fasten and secure bolts in place. Their grade must match or be higher than the paired bolt. Automotive nuts are used in many functions but can be used in more complex applications where a t-nut, locking nut, and collar nut may be used.

Automotive Studs: Automotive studs are threaded on both ends and have an unthreaded middle section and are secured to materials using nut screws. Studs are made from numerous materials, including bronze, copper, brass, or plastic. Studs are commonly used in the build of an automotive engine, to secure the gasket head and cylinders, or situations that need a higher stress tolerance than what bolts are capable of providing.

Marine Fasteners

The greatest challenge for fasteners used in marine applications is the corrosive threat posed by saltwater. The higher presence of wood materials also means that galvanic corrosion and crevice corrosion are common issues. Marine fasteners are sorted by their materials and intended use.

Stainless Steel: most marine fasteners are made from stainless steel. Stainless steel offers the optimal strength and rigidity for marine applications and is highly resistant to corrosion. CRES Series Steel 18-8, 304, and 316 are used in the marine industry, and 316 offers the highest corrosion resistance.

Hot Dipped Galvanized Fasteners: Some fasteners undergo a process where they are dipped in a layer of zinc, creating a bonded alloy. Fasteners that undergo this process have greater tensile strength and are more resistant to corrosion than standard stainless steel. Zinc-plated steel is considered to be the best choice for engine applications. Fasteners of this type are also used in functions with higher loads, such as the shaft coupler.

Silicon Bronze: Silicon bronze is made from copper, with silicon and corrosion-resistant alloys like zinc. Silicon bronze fasteners are used in components that frequently contact water, applications below the waterline, and wooden vessel construction. Silicon bronze is very resistant to corrosion from chemicals and operates well in the absence of oxygen. It is also far less likely to galvanize other metals it is secured to.

Aerospace Fasteners

Fasteners used in the aerospace industry are similar in function and appearance to fasteners used in other industries, but differ significantly in terms of material, weight, and quality. Aerospace fasteners operate in environments that bring risks of corrosion, extreme stress and loads, high pressures, and exposure to extreme temperatures. This requires aerospace fasteners to have higher standards for design, manufacturing, and choice of materials.

Aluminum: Aluminum is a popular choice for making fasteners in aircraft, but not spacecraft, because it requires extra treatment before it is ready for spacecraft. Aluminum must be cold-formed, is vulnerable to corrosion caused by stress, and is not optimal if expected temperatures will exceed 350 degrees Fahrenheit.

Steel: Steel is strong, but heavy, which is a recurring problem for aircraft components. Stainless steel and alloys are the most common types of steel used in the aerospace industry. CRES Steel Series 300 is most often used for screws and bolts. It is sensitive to higher temperatures, but resistant to corrosion. Series 400 is more vulnerable to rust but has higher heat resistance. Alloy steels are durable, but vulnerable to corrosion.

Superalloys: Superalloys are often used in aerospace because they are strong, versatile, and can withstand extreme temperatures. Superalloys include H-11, Hastelloy, Monel, K-Monel, Haynes, A286, MP35N, and MP159. Choosing the right superalloy depends on the stresses the fastener will be exposed to.

Titanium: Titanium is as strong as steel, and lighter as well.