Rivets play an important role in the aerospace manufacturing industry. Like all fasteners, they are used to hold two or more parts together. Rivets, however, are permanent fasteners that resist external forces like vibrations. They don’t have threading like bolts and screws, so they won’t loosen when exposed to vibrations. While all rivets are classified as permanent fasteners, they are available in different styles, one of which is flush.
What Are Flush Rivets?
Flush rivets are characterized by their ability to sit flush with the surface on which they are installed. Also known as countersunk rivets, they create a smooth surface. Flush rivets are still used to hold two or more parts together, but their countersunk design promotes a smooth finish with the outer surface of the parts.
With their countersunk design, flush rivets are commonly used in the aerospace manufacturing industry. They don’t have a raised head. Once installed, the head of a flush rivet will sit flush with the outer surface of the parts.
How Flush Rivets Work
How do flush rivets work exactly? Like all rivets, they feature a head and shank. The shank is the long and cylindrical portion of a flush rivet that’s driven through the parts, whereas the head is the larger top portion. The end of a flush rivet opposite to the head is the tail. During installation, the tail is buckled or deformed to secure the flush rivet in place.
Flush rivets require a countersunk hole for installation. Before installing a flush rivet, you’ll need to make a hole through the parts. The hole, however, must accommodate the rivet’s head. If it’s a plain, straight hole, the head will protrude out the top. Installing a flush rivet requires a specialized hole that’s able to support a countersunk head.
Why Flush Rivets Are Used on Airplanes
Flush rivets are a popular choice of fasteners for airplanes because of their ability to reduce drag. Other types of rivets have a protruding head. The head of a traditional rivet will stick out of the parts with which it’s used, resulting in increased drag. And considering that many airplanes have hundreds or thousands of rivets, that’s a lot of added drag.
Flush rivets don’t have a protruding head. They are designed specifically so that the head rests at the same level as the top surface of the parts, thereby creating a flush finish. This reduces drag, which in turn makes airplanes more fuel-efficient.
