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
- Patch bolt
- Lock washers
- Disk lock - wedge type
- Jam nuts
- 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.