What Are Captive Fasteners?

Whether constructing a simple piping system or a robust aircraft structure, fasteners prove to be one of the most crucial components for assembly, load bearing, and more. Fasteners are mechanical devices, designed to conjoin or affix two or more components together in a permanent or non-permanent fashion. Within the aerospace industry, a number of fasteners are used to join together aircraft parts, allowing for structures to withstand the various extreme conditions that aircraft are subject to during typical flight operations. In this blog, we will discuss the captive fastener which is a type of screw that is commonly used for many types of assemblies.

With a captive fastener or captive screw, a permanent attachment or securement of components can be formed through installation in a pre-drilled hole. Similar to more common types of screws that are used within the aerospace industry, captive fasteners also feature external helical threading across their shaft as well as a head on the top. Despite this similarity, captive screws differ from traditional screws in the fact that they can be fastened and removed without having to detach the screw from the pilot hole that it is installed in. As such, more conventional screws are not optimal for installations and applications that may require removal of the aerospace fastener without detaching it from the pilot hole. With a captive screw, the screw remains inside of the pilot hole after installation, allowing for the surface that it was installed in to be free.

Captive fasteners are specifically engineered in order to provide a permanent hold through captivation, and their hold is achieved through a target assembly or housing. If there is a need for an anchor hold, a captive fastener may be designed with thread locking, broaching, press-fitting, or other anchor parts. Additionally, captive screws may also be installed onto an assembly through the use of cold forming or welding, guaranteeing a permanent fastening. As a type of machine screw, captive fasteners prove very beneficial for safety applications and assemblies, typically installed alongside a captive washer for a complete fitting.

As captive fasteners are installed to create permanent hold within pilot holes, they are typically not subjected to the same degradation that more conventional screws face with age. Captive fasteners are also beneficial in applications where there are high levels of vibration and physical forces, as they will not leave the pilot hole even when becoming unfastened. As such, captive screws are much more useful for the assembly of aerospace parts and aircraft components where traditional screws may easily become loose due to physical stressors.

As such, captive fasteners prove to be beneficial for a wide range of applications in which the capabilities of a screw are insufficient. Captive screws and fasteners may also be found in various materials depending on the need, though the most common type is the stainless steel screw with a passivation finish. Additionally, a number of head types may be chosen from such as head and pan head styles, each providing their own unique benefits for installation.

When it comes time to procure the aerospace fastener products that you need to carry out your operations, look no further than Vertible Aerospace. Veritable Aerospace is a leading online distributor of aircraft parts, offering customers access to an unparalleled inventory that has been sourced from countless top global manufacturers. We invite you to peruse our part catalogues at your leisure, and you may begin the purchasing process at any time by filling out and submitting an Instant RFQ form as provided through our website. Get started today and see how we can serve as your strategic sourcing partner for all of your operational needs.