Spiralock Corporation has transformed the standard internal thread profile into a self-locking female thread form with the addition of a unique 30° wedge ramp at the root of the thread. This unidirectional locking feature, called Spiralock®, is compatible with standard 60° male thread fasteners.
The wedge ramp allows male fasteners to spin freely relative to the female threads until clamp load is applied. At that point, the crest of the standard male threads is drawn tightly against the wedge ramp, creating a continuous spiral line of contact along the entire length of the thread engagement. As clamp load increases, the wedge ramp pushes against the male thread from all sides, eliminating the radial clearance that allows fasteners to begin self-loosening under vibration.
Why use Spiralock thread form? Read here about the advantages of replacing standard locking methods with Spiralock.
Testing on Junker vibration equipment has proven that the Spiralock thread form outperforms other thread locking devices.
The load carried by Spiralock threads is more uniform than 60° threads. Load percentage on the first engaged Spiralock thread is significantly lower.