How to Choose the Right Aerospace Fastener for Your Application

Fasteners are some of the smallest components found in aerospace assemblies, yet their role in ensuring safety, structural integrity, and performance cannot be overstated. From holding fuselage panels in place to securing engine components reliably in the face of immense stress, the right fastener ensures the overall reliability of countless aircraft. As aviation applications regularly involve demanding environments where high loads, vibration, and extreme temperature fluctuations are common, selecting the appropriate fastener is an important process that necessitates careful consideration and basic industry knowledge of hardware options.

In this blog, we will offer a detailed guide on how to choose the right aerospace fastener for a particular application, covering important topics like common fastener types, material considerations, and relevant standards. We will also conclude with guidance on where to source quality-assured options, so be sure to read on to learn more!

What Are Common Types of Aerospace Fasteners?

Aerospace fasteners come in many forms, with individual options being uniquely designed for particular applications or assembly needs. As such, having an understanding of their basic properties and use cases can help engineers and maintenance professionals select the most appropriate fastener for any given assembly.

Bolts and Screws

Bolts and screws are considerably some of the most notable fasteners across aerospace applications, both being externally-threaded shafts that can reliably secure parts together. Bolts in particular are high-strength fasteners that are popular in areas requiring secure joints that can withstand heavy loads, often being paired with nuts and washers to maintain joint integrity. Screws, meanwhile, are able to be directly inserted into tapped holes to attach access panels, interior components, and other non-structural assemblies.

Bolts and screws both come in a range of subtypes, with popular options including hex-head bolts, pan-head screws, and socket-head screws.

Nuts and Washers

As already mentioned, nuts and washers are regularly used to support bolts and other threaded fasteners. While standard nuts are tightened to the tail-end of a bolt to hold items in place, more specialized options like locking nuts are useful for preventing fasteners loosening from vibration. On the other hand, washers are commonly employed to distribute loads, reduce friction, and prevent fasteners loosening under stress.

Rivets

Rivets are a form of permanent fastener that is able to secure assemblies with high levels of security, a range of subtypes being commonly used across aircraft and aerospace assemblies. Solid rivets are a basic option that are useful for joining aircraft skin assemblies and wing structures, as they resist vibration and offer a flush finish. For structures that provide access to one side only, blind rivets are a more specialized type that are more ideal for confined areas.

Pins

Clevis pins and cotter pins are often leveraged to secure assemblies that need occasional disassembly, such as linkages. Taper pins are also popular in aerospace applications, providing precise alignment in control mechanisms and other critical assemblies.

Important Material Considerations

Beyond determining what basic type of fastener may be needed for a particular application, material choice is also one of the most critical aspects of selection. This is because the material that a particular fastener is made from will have a direct impact on its load-bearing properties and weight, as well as its ability to resist corrosion, temperature extremes, fatigue, and other common stressors of aerospace operations.

Aluminum Fasteners

Aluminum offers the benefit of being lightweight and corrosion resistant, driving its use for fasteners installed in low-load applications. Despite being very reliable for aerospace applications, aluminum fasteners are not ideal for high-temperature zones like engines, as they will degrade under such intensive heat.

Titanium Fasteners

Comparable to aluminum, titanium similarly offers an excellent strength-to-weight ratio. Additionally, it is also resistant to corrosion and fatigue, making it suitable for fasteners used for airframe and engine applications. While preferred in weight-critical applications, titanium is more expensive on average.

Steel and Stainless Steel Fasteners

8740 steel alloys and corrosion-resistant stainless steels are both commonly used for structural components as a result of their high strength. Superallows like inconel and monel are also useful for their extreme temperature and stress resistances, driving their use in turbine engine and exhaust assembly fasteners. Despite these various benefits, these materials are heavier than titanium or aluminum, limiting their application in aerospace settings that prioritize weight.

What Are Aerospace Standards?

Aerospace fasteners regularly adhere to rigorous industry standards to ensure their reliability and interchangeability across global platforms. When selecting any fastener, professionals should always check which standards apply to their specific application. The following are some of the most recognized standards of the industry, ensuring that you are familiar with the basics.

Military Standards (MS): Widely adopted by defense and civil aviation manufacturers alike, MS fasteners follow precise requirements for dimensions, materials, and handling to ensure they meet goals for interchangeability and performance.
Aerospace Standards (AS): Published by SAE International, aerospace standards cover a broad range of hardware products, often superseding military specifications in a range of modern programs.
National Aerospace Standards (NAS): NAS specifications are often focused on the design and manufacturing of high-performance fasteners, particularly those used in structural and engine-related assemblies.
AN Standards (Army-Navy): Somewhat older, AN standards are still relevant in certain legacy aircraft systems for the purpose of promoting safety, quality, interchangeability, and consistency across parts.

Ensuring compliance with any necessary specification or standard will effectively reduce the risk of incompatibility and ensure that fasteners can perform reliably under expected conditions.

Where to Source Aerospace Fasteners with Confidence

For those seeking dependable aerospace fasteners for demanding applications, Alpha NSN offers access to a wide selection of quality-assured parts that are strictly sourced from trusted manufacturers and suppliers. With our unwavering adherence to strict industry standards and rigorous quality control practices, Alpha NSN provides the confidence needed to maintain safe and efficient operations across aviation applications. Take the time to explore our wide-ranging product options today, and once you narrow down items of interest, you can always kick off procurement with ease using our online Request for Quote (RFQ) forms.