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.

Thread Form Benefits


Why Use Spiralock® Thread Form?:

  • Exceptionally resistant to vibration loosening
  • Eliminates need for other locking devices
  • Compatible with standard male fasteners
  • Free spinning
  • Consistent reusability
  • Improves joint fatigue life

Vibration Loosening Resistance


Testing on Junker vibration equipment has proven that the Spiralock® thread form outperforms other thread locking devices.

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Load Distribution


The load carried by Spiralock® threads is more uniform than 60° threads. Load percentage on the first engaged Spiralock® thread is significantly lower.

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See it Work

Spiralock® Products

Watch Spiralock® in animated clips showing the Morphing Animation, Load Vector Comparison, and Photoelastic Analysis.

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