Aerospace Fasteners: The Ultimate Guide to Types, Materials, and Standards

A single modern aircraft relies on millions of fasteners to hold its structure together under immense stress, extreme temperatures, and constant vibration. These aren't your everyday hardware store screws and bolts; they are precision-engineered components where failure is not an option. Aerospace fasteners are fundamental to the safety, performance, and integrity of everything from commercial airliners to space-bound rockets.

For engineers, procurement managers, and designers, sourcing the right aviation nuts and bolts is a critical task that balances rigorous standards with practical manufacturing needs. This guide will provide a comprehensive overview of these essential components, breaking down the types, materials, and standards you need to know. We'll also explore what to look for in a manufacturing partner capable of delivering the quality and reliability the aerospace industry demands.

Aerospace fasteners are specialized hardware devices designed to join parts and components within an aircraft or spacecraft. Unlike standard fasteners, they are engineered to perform reliably in the harsh conditions of aviation and space flight, including extreme pressure, temperature fluctuations, and corrosive environments.

Their primary role is to ensure the structural integrity of the aircraft. They assemble major aerostructures like the fuselage, wings, empennage (tail section), and flight control surfaces. Without these high-strength, lightweight fasteners, the advanced machines we rely on for travel and exploration would simply not be possible.

Key Characteristics of Aviation Fasteners

• High Strength: They must exhibit exceptional tensile, shear, and fatigue strength to withstand dynamic loads like heavy turbulence.
• Lightweight: With millions of fasteners used per aircraft, reducing weight is crucial for fuel efficiency and overall performance. Materials like titanium and aluminum are favored for their high strength-to-weight ratio.
• Corrosion and Oxidation Resistance: Exposure to atmospheric elements and varying altitudes requires excellent resistance to degradation.
• Thermal Resistance: Fasteners must maintain integrity across a wide temperature range, from frigid high-altitude cold to the intense heat of engine compartments or atmospheric re-entry.
• Reliability and Certification: They must pass stringent quality standards (like AS9100) to ensure consistent performance and safety.

Aircraft construction uses a variety of fasteners, each chosen for a specific purpose. They can be broadly categorized into standard and special fasteners.

1. Aircraft Bolts
Aircraft bolts are used in structural assemblies requiring high strength, such as wing attachments and landing gear. They are typically made from corrosion-resistant steel, cadmium, or anodized aluminum alloys. Common types include MS (Military Standard), NAS (National Aerospace Standard), AN (Army-Navy), and close-tolerance bolts, which are manufactured to precise dimensions for a tight fit.

2. Aircraft Nuts
Always used in conjunction with a bolt, aircraft nuts are threaded fasteners made from materials like cadmium-plated carbon steel or anodized aluminum. A key feature is their locking mechanism to prevent loosening from vibration. There are two main types: non-locking nuts (often used with a lock washer) and self-locking nuts (which feature a nylon insert or other mechanism to create friction).

3. Aircraft Screws
Screws are common thread-fastening methods, typically used for non-structural applications like attaching access panels. They are generally made from lower-strength materials than bolts and have a loose-fitting thread.

4. Aircraft Rivets
Rivets are permanent fasteners with a smooth cylindrical shaft and a head on one end. They are installed by placing the shank into matched holes in materials and deforming the tip to create a second head, clamping the parts together securely. They are extensively used in joining fuselage and wing skins.

Beyond standard nuts and bolts, aircraft use advanced fasteners designed for specific challenges.

Hi-Lok and Lockbolts

Hi-Lok pins are two-part fasteners (a pin and a collar) that provide a consistent preload and are installed to a preset torque. The pin shears off at a specific torque, ensuring a uniform and reliable clamp. Lockbolts (or huck bolts) are a hybrid between a bolt and a rivet, offering high strength and vibration resistance while being lightweight. They are common in structural components like wing splice fittings.

Blind Fasteners

Blind bolts and rivets are indispensable when only one side of the workpiece is accessible. The fastener is inserted and tightened from one side, making them ideal for hard-to-reach areas within an aircraft's structure.

Turnlock Fasteners

Turnlock fasteners (like those made by Dzus or Camloc) provide quick access for inspection and maintenance. They are used to secure removable panels, doors, and cowlings, allowing for easy removal without tools.

The material choice is critical to achieving the required characteristics.

Table: Aerospace Fastener Materials, its key properties and applications

Rigorous Quality Management

The aerospace industry operates under strict quality standards to ensure safety and reliability. The AS9100 series is the internationally recognized Quality Management System standard for organizations that design and manufacture aerospace components. Working with an AS9100-certified manufacturer, like clarwe, is non-negotiable for ensuring that every fastener meets the highest quality benchmarks.

Precision Installation

The best fastener is only as good as its installation. Proper installation involves precision drilling, careful torque control, and specific techniques like cold working holes to improve fatigue life. Following precise aircraft fastener installation directions is critical to creating a joint that will perform as intended over the lifespan of the aircraft.

Selecting a supplier for aircraft fasteners is a decision that impacts safety, cost, and project timelines. Here are key considerations:

• Expertise and Experience: Look for a manufacturer with a proven track record in producing precision components for the aerospace sector.
• Quality Certifications: AS9100 certification is a must-have, demonstrating a commitment to rigorous quality control.
• Advanced Capabilities: Your partner should have expertise in CNC machining for aviation, including screw-machining, and the ability to work with the materials and standards you require.
• Collaborative Approach: An ideal partner acts as an extension of your team, offering design for manufacturability (DfM) feedback to optimize parts for production.

At clarwe, we understand the critical nature of aerospace fasteners. As an on-demand manufacturer, we combine the agility and speed of a digital platform with the technical expertise of an aerospace specialist. We are equipped to produce high-quality, custom fasteners that meet National Aerospace Standards (NAS), helping you stay ahead of schedule without compromising on quality.

Aerospace fasteners may be small, but their importance is enormous. From common aircraft bolts and nuts to specialized Hi-Lok pins and blind rivets, each component plays a vital role in the safety and performance of an aircraft. Understanding the types, materials, and rigorous standards behind these fasteners is the first step in making informed sourcing decisions.

In an industry where precision and reliability are paramount, choosing the right manufacturing partner is crucial. clarwe is committed to being that partner, providing the high-quality aerospace hardware you need with the speed and flexibility of an on-demand service.

Ready to get a quote for your aerospace fastener needs?
Contact clarwe today to leverage our manufacturing expertise and ensure your projects are built on a foundation of quality and reliability.

What is the difference between structural and non-structural fasteners?

Structural fasteners are designed to carry aircraft loads and are critical to the airframe's integrity. Non-structural fasteners connect parts that do not bear significant loads, such as interior panels or access covers.

Where is an AN clevis bolt used in an airplane?

An AN clevis bolt is commonly used in flight control systems for linkages, such as connecting control rods, bellcranks, and other components that require a pivoting connection.

What are the key advantages of titanium fasteners?

The primary advantages are their high strength-to-weight ratio and excellent corrosion resistance. This makes them ideal for reducing weight in critical structures without sacrificing performance, though at a higher cost.