When it comes to aviation and fasteners the first image that comes to mind is a screw. It is one of the most popular pieces of hardware. But with popularity comes variety and too much variation can be confusing. That's why SkyGeek is here to add clarity to your purchasing decisions.

As mentioned, screws are fasteners, particularly threaded fasteners. Threading offers more strength and rigidity and in this way threaded fasteners are more practical than rivets.

One of the main problems with screws is figuring out how they are different from bolts. Like bolts, screws have a head and a threaded section. The threaded end of a bolt, however, is usually blunt whereas a screw may be blunt but is often pointed. Also, bolts have a relatively short threaded section and a relatively long grip length; a screw may have no clear grip length. A bolt head may or may not need turning while a screw is specifically designed so as to be turned by its head. While there is no official distinction, a general rule of thumb is this: bolts require a nut when screwing in the threaded end; screws, on the other hand, may use a nut but is generally secured directly into the affected area.

Screws are designated by type, three of the most common in aviation being machine, structural, and self-tapping. Machine screws are designed with finer threads and made with better precision; they are often used with nuts or tapped holes. Structural screws are strong and make durable connections. Self-tapping screws, as its name indicates, creates its own threads as it is driven into a hole.

Determining the difference among screw heads is essential in picking the right one. Common screw heads are: countersunk, round, brazier, flat, fillister, pan, truss, and socket. In addition, screw heads have different slots in them including straight, Phillips, and Reed and Price.

A screw's composition is vital in knowing its strength. Steel is quite common as well as its variations (e.g. corrosion resistant, carbon, etc.); aluminum, brass, bronze and copper screws are available as well. Moreover, screws sometimes have surface treatments and finishes—cadmium is frequently employed.

SkyGeek's inventory of screws continues to expand. We offer screws that conform to U.S. military standards and specifications. In order to zero in on what you need, examine each series of screw and compare their size and length to match the right screw for the proper application.