A Summary of Aircraft Fasteners

Despite aircraft being built from the highest quality materials, those materials would be rendered obsolete if they were not properly affixed to one another. This is where fasteners come in. Though they are small, seemingly insignificant parts, fasteners are the most critical part of an aircraft. Without them, aircraft could not be assembled, let alone withstand the extreme conditions they are subjected to during flight. In fact, in an entire aircraft, roughly half of all parts are fasteners.

To withstand the extreme stresses they are subjected to, and improve the overall safety and efficiency of an aircraft, all aircraft fasteners must adhere to strict standards related to their production and use. Due to their high precision and superior quality, aircraft fasteners are also used in machinery that require precise components. They are highly resistant to corrosion and oxidation, feature high tensile, shear, and fatigue strength, are light weight, able to self-seal and self-lock, and able to withstand harsh environments such as extreme temperatures.

In aerospace, there are five core types of fasteners: screws, bolts, nuts, rivets, and washers. Screws are the most commonly used threaded fastener in aircraft. They are characterized by a helical ridge, also known as an external thread. In comparison to bolts, they are typically made of lower strength materials and can be installed with a loose fitting thread. The bolts used in aircraft structures are usually general purpose, AN bolts, NAS internal wrenching or close tolerance bolts, or MS bolts. Aircraft bolts can be manufactured from materials such as cadmium- or zinc-plated corrosion-resistant steel, unplated corrosion-resistant steel, or anodized aluminum alloys.

A nut is a type of fastener with a threaded hole. Nuts are always used in tandem with a mating bolt or screw. These can be made from cadmium-plated carbon steel, stainless steel, or anodized 2024T aluminum alloy, and are further categorized into self-locking and non self-locking nuts. Aircraft rivets are permanent mechanical fasteners consisting of a smooth cylindrical shaft with a head on one end. Rivets are used to join two or more metal sheets, plates, or other pieces of material. The shank of the rivet is placed through aligned holes in two pieces of material, and the tip is then deformed to create a second head to securely clamp the two pieces together. Lastly, aerospace washers include plain, lock, or special washers fabricated from strong and lightweight materials.

As fasteners have so many different uses, they can be made from many materials depending on their intended end use. The four most common materials are titanium, aluminum, steel, and superalloys. Titanium is an ideal material for aerospace fasteners due to its high strength to weight ratio. Its strength is comparable to steel, but is much lighter. Aluminum is a lightweight and affordable material primarily used for atmospheric planes and other exterior components. However, aluminum has certain limitations and may need additional surface treatments.

Steel can be more than three times the strength of aluminum but is also heavier, which is the main issue to consider when using steel fasteners. Stainless steel and alloy steel are the most common types found in fastener materials, such as the aircraft surface and landing gear. Finally, superalloys are a special kind of material used in aerospace. They are popular due to their array capabilities when compared to other materials. These include high versatility, the ability to maintain structural and surface integrity in harsh environments, and their resistance to creep.

Whatever type of aerospace fastener you need, ASAP Fasteners, a trusted supplier of all kinds of aerospace parts and much more, is the ultimate source. Owned and operated by ASAP Semiconductor, we are an online distributor of aircraft parts as well as parts pertaining to the aerospace, civil aviation, defense, industrial, and electronics markets. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, call us at 1-714-705-4780 or email us at sales@asap-fasteners.com.


November 5, 2020

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