The Different Types of Fasteners Used in Aircraft Assembly

Aircraft assembly is a highly complex process that relies on thousands or even millions of individual components coming together to form a safe, reliable, and airworthy structure. Among the many components that make up a particular aircraft, fasteners serve a significant role, making up a large portion of any build. Simply put, fasteners are responsible for securing diverse assemblies across aircraft, distributing structural loads and ensuring the long-term integrity of airframes and subsystems.

As aircraft face extreme conditions during flight like vibration, pressure changes, and thermal stress, the fasteners chosen for any assembly must meet stringent performance requirements and expectations. Understanding the different types of fasteners used in aviation applications highlights their importance and sheds light on why careful selection is vital, so read on as we discuss the most common options on the market.

Bolts

Bolts are among the most common fasteners used for assembling aircraft, featuring externally threaded shafts that can pair with mating components like nuts and washers to dependably secure assemblies while bearing significant structural loads. For aviation use, bolts are typically made from materials like high-strength steel, titanium, or corrosion-resistant alloys, ensuring that they can withstand environmental stressors without adding too much weight to the vehicle.

Notable Classifications: Bolts used for aircraft are often engineered to meet Army-Navy (AN), Military Standard (MS), and National Aerospace Standard (NAS) specifications, all of which serve to specify material composition, thread dimensions, tensile strength, and other important attributes.
Applications: Across aircraft, one will typically find bolts in wing-to-fuselage joints, landing gear structures, and engine mounts where high-strength fastening solutions are highly desired.

Rivets

Rivets are the quintessential fastener for joining thin sheets of metal in aircraft structures. While somewhat similar in appearance to bolts with a shaft that has a head on one side, rivets are typically non-removable and form a permanent bond once installed. They are also made from lightweight yet durable materials like aluminum, titanium, and monel, allowing them to achieve an optimal balance of strength and weight.

Subtypes: Solid rivets are the most common variation, simply requiring a bucking bar and hammer for installation. Meanwhile, blind rivets are more specialized options that are used in areas with limited access, allowing installation from one side of an assembly. Lastly, flush rivets are notable for their role in reducing aerodynamic drag by sitting even with the aircraft surface they are installed in.
Applications: Rivets are widely used in fuselage skin sections, wing panels, and control surfaces where aerodynamic smoothness and reliable strength are required.

Nuts

Nuts are the fastener that is most commonly paired with bolts to create secure connections that resist loosening under vibration, their internal threading accommodating the matching threads of other hardware. In aviation, nuts are engineered to exacting standards to ensure their reliability in challenging operating conditions.

Subtypes: Common aviation nut types include self-locking nuts, castellated nuts, and wing nuts, each generally varying in shape and capability.
Applications: Nuts are widely used across aircraft, ranging in application from securing landing gear assemblies to engine housings. As a rule of thumb, one can expect to find nuts in most places where bolts are found.

Screws

Screws are another essential fastener category, such hardware being valued for its ability to be installed and removed with ease. While featuring the same externally threaded shafts that can bore their own holes, aviation screws differ from standard industrial screws in that they are manufactured to tighter tolerances and specific aviation standards. They also tend to prioritize a balance of strength and corrosion resistance by leveraging materials like stainless steel, titanium, or nickel alloys.

Subtypes: Machine screws, structural screws, and self-tapping screws are all common in aircraft assembly, many being designed with specialized heads to prevent tool slippage during installation.
Applications: Screws are widely relied on to secure interior paneling, access doors, instrument panels, and avionics housings throughout aircraft, providing secure fastening with accessibility for maintenance.

Washers

Often coming in the form of flat discs with a hole in the middle, washers are commonly paired with other fasteners to distribute loads, prevent surface damage, and ensure consistent torque. Washers are typically installed between the head of a fastener and the installation surface, constructed from lightweight metals or high-strength alloys to meet performance requirements.

Subtypes: Flat washers are a common option used to evenly distribute loads, while lock washers take advantage of specialized designs to prevent fastener loosening resulting from vibration. Countersunk washers are another notable option, made to facilitate flush installation when they are paired with screws and bolts.
Applications: Washers are used in nearly every bolted or screwed connection, supporting everything from structural assemblies to interior fittings.

Pins

As the last major category of fasteners, pins are often necessary for aligning components or transferring shear loads across aircraft assemblies. While somewhat similar in appearance to bolts in terms of featuring rigid shafts, pins are not always threaded and are often designed for exact fits in specific components.

Subtypes: Clevis pins, cotter pins, and taper pins are all common examples of pin subtypes, each being unique in capability and design. For example, cotter pins are often used in conjunction with castellated nuts to secure assemblies, while taper pins are valued for their secure fit in critical load-bearing applications.
Applications: Pins are most often employed in control linkages, landing gear assemblies, and engine components where alignment and secure load transfer are major concerns.

Ensure Reliability Through Quality Sourcing

As quality fasteners are integral to aircraft safety, sourcing such hardware from trusted channels is essential to ensure long-term reliability and airworthiness. Here on Alpha Purchasing, we can connect you with a wide ranging selection of aviation fasteners and certified aircraft parts, our stock being sourced from leading manufacturers and suppliers across the globe.

Narrow down items of need by part number, NSN information, FSC data, etc. with our curated catalogs, and once you are ready to discuss options, our team is just a call, email, or RFQ form away from providing hands-on support. To see why so many customers steadily depend on Alpha Purchasing for diverse fastener fulfillment, get in touch with us at your earliest convenience.