Socket Shoulder Cap Screws, Nylon Patch/Pellet

Socket shoulder cap screws are often called shoulder bolts or shoulder screws due to the key component that sets them apart from the socket product family- the shoulder. A socket shoulder screw has a raised cylindrical head that is often knurled, the same head design as found in socket head cap screws. Installation is completed the same too with a hexagon drive tool, such as a hex key. The hexagon drive is advantageous for those installations with limited space, allowing a user to apply the appropriate torque using a standard Allen wrench.  Directly below the bolt head is the key element, an unthreaded section or the shoulder. Lastly, a threaded shaft is found at the far end of the bolt. Fasteners Etc. Inc. offers socket shoulder cap screws in black oxide coated steel with a nylon patch and nylon pellet.  Both nylon patch and pellets are designed to prevent the threaded portion of the screw from loosening; however, they differ in functionality and application. Both options are heavily utilized in mechanical applications with vibration or movement.

A nylon pellet is a small, cylindrical insert made of nylon. It is a separate component added to the threading of the screw. As the screw is installed and tightened, the nylon distorts causing friction and further securing the hold. Screws with nylon pellets may be multi-use so long as the user inspects the nylon to ensure no damage has occurred. 

A nylon patch is a coating applied to the screw’s threading during manufacturing. There are after-market options for thread locking material that can be applied on site; however, this option increases labor costs and installation time to allow for dry-time. The nylon patches are often colorful to help the user easily identify the nylon patch from the bolt threads. It succeeds by creating friction between the bolt threads and base material. Screws with nylon patches may be multi-use; however, the patch will wear over time and requires inspection.