Socket Head Cap Screws

Socket hex head cap screws are externally threaded machine screws with an internal hex socket drive which corresponds to a hex key or allen wrench. Because the screws are internally wrenched, they require less surface area and are thus ideal for projects where there is insufficient space for traditional wrenches or sockets.

Socket head cap screws, or allen screws, can be either fully or partially threaded. On fully threaded varieties, the thread length equals the screw length, and the screw can be installed all the way into a threaded hole. Conversely, partially threaded screws have an unthreaded portion under the head and therefore, the thread length varies. Because the unthreaded portion of the screw is stronger than the threaded section, partially threaded screws possess more holding power when force is applied from the side.

AFT's socket cap screws are available in metric and inch sizes in a wide range of diameters and lengths. Use the menus to the left to narrow your search for the right socket head cap screw. Additionally, you'll find that most of the head cap styles are available with either nylon-patch or nylon-pellet self-sealing threadlocking modifications for added holding power. Our most popular products are the stainless steel socket head cap screws, but we also offer silicon bronze and Ni-Cu Alloy Steel. Should you not find the modification or finish that you desire on our website, please let us know. With on-site plating and coating facilities, we are able to customize any fastener with your desired modifications, including painting, plating, drilled holes and custom lengths. Contact us or request a quote to learn more from our experienced sales representatives.

Socket Head Cap Screw Resources

Frequently asked Questions

Q: What grade are socket head cap screws?

A: Standard inch socket head cap screws are not designated by a grade like hex cap screws. A standard inch socket head cap screw is 20% stronger than Grade 8 hex cap screws and 50% stronger than Grade 5 hex cap screws. Metric socket head cap screws are designated by classes - Class 8.8, Class 10.9 & Class 12.9.

Q: Do socket head cap screws need washers?

A: Washers aren't commonly required when using socket head cap screws. Exceptions may include applications with soft materials or irregular surfaces. If a washer is needed, try using a hi-collar split lock washer.