The diverse aircraft screw

Screws are a type of fastener that feature a helical external threading that wedges and digs into the component it is installed into as it is tightened. As torque is applied and the screw is driven in, materials are pulled in tightly to prevent easy removal of the screw. Materials that screws are used in can include wood, sheet metals, and plastics. The most common material that is used to manufacture screws is steel, though stainless steel, titanium, brass, bronze, and other screw types are also available. Screws are the most commonly used threaded fastener on aircraft, having many different applications. While many variations of screws exist, they are generally classified in three groups: structural, machine, and self-tapping.

Structural screws are made of alloy steel, heat treated, and can be used as structural bolts. These aerospace screws have a defined grip and the same shear strength as bolts of the same size. Shank tolerance of structural screws are similar to that of AN (Air Force & Navy standard) hex head bolts. These screws are available with round, brazier, or countersunk heads. The AN509 flathead screw is an example of a structural screw, used in countersunk holes where a flush surface is required. Another example, the AN525 washer head screw, is used in applications where a raised head is acceptable.

Machine screws usually feature flathead (or countersunk), roundhead, or washer head types. These screws are used for general purpose applications and are made in different materials such as low carbon steel, brass, corrosion resistant steel, and aluminum alloy. Roundhead screws such as AN515, AN520, AN505, AN510, AN500, AN503,are all examples of machine screws.

Self-tapping screws typically consist of a round head and are countersunk by 82 degrees. These screws are used to attach removable parts such as nameplates, castings, and parts in which the screw cuts its own threads. Examples of self-tapping screws include the AN530 and AN531, which are made from sheet metal. These screws are often used in the temporary attachment of metal for riveting, as well as in the permanent assembly of nonstructural assemblies. As self-tapping screws are tailored for light, temporary use, they should not be used to replace standard screws, nuts, bolts, or rivets.

At ASAP Purchasing, owned and operated by ASAP Semiconductor, we can help you find all the aircraft screws for the aerospace, civil aviation, and defense industries. 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, email us at sales@asapsemi.com or call us at 1-714-705-4780.