Vibration Loosening Resistance

Test Parameters: ¼”-28 nut run @ 20 Hz with ±0.033” amplitude of transverse movement.

Extensive testing on Junker’s transverse vibration equipment has proven that the Spiralock internal locking thread form outperforms other thread locking devices. In fact—unlike other locking devices, which lose preload within the first minute of testing—Spiralock joints remain tight until the bolts fail due to fatigue.

Goddard Space Flight Center also determined that the Spiralock thread form was the only product able to withstand the vibrations imposed by the Space Shuttle's solid rocket boosters. Even tests that exceeded specifications for the Space Shuttle by a factor of 10x did not cause Spiralock fasteners to loosen.

Spiralock vs. Other Locking Features

  • Adhesive
  • Patch bolt
  • Lock washers
  • Disk lock - wedge type
  • Serrations
  • Jam nuts
  • Lockwire
  • Cotter pin
  • Tab lock
  • Prevailing torque
    • All metal
    • Nylon ring
    • Interference fit

None of these “fixes” address the root cause of loosening! They are primarily a fail-safe to hold the hardware after loss of tension. Spiralock modifies basic joint behavior instead of relying on thread friction.