Vibration Testing


DIN 65151



CoiLok™ has been tested against applicable testing standards and shown to meet and exceed the strict safety performance requirements demanded in the wide range of industries and applications in which locking fasteners are used.

CoiLok™ provides real world bolting security that works. Period.

Junker Test (DIN 65151)


Known as the Junker Test, this test measures the effect of transverse vibration on a bolted joint.

The test is performed on a Junker test rig, vibrating the joint at a predefined frequency and amplitude, measuring changes in clamp load of the joint from the start of the test until its end.


Bolt Size: M8
Frequency: 12.5 Hz
Amplitude: ±1 mm
Duration: 1600 cycles


Testing was performed to ensure locking performance well over the number of vibration cycles required. CoiLok™ maintained locking throughout the test, displaying excellent vibration resistance.


CoiLok™ was tested under the strict guidelines of the military and aerospace standard NASM 1312-7 severe vibration impact test.

This test also makes up the vibration/impact testing portion of the US NAS 3350/3354 standard impact shock vibration test. This testing verified that all types of CoiLok™ locking fasteners exceed this evaluation standard by a clear margin.


CoiLok™ is designed for use in a wide range of applications exposed to vibrations and impacts on a continuing basis. Whether land or air transportation vehicles, machinery, bridges, or any other critical joints, CoiLok™ can be relied upon as meeting the standards.


Standard Test Duration: 17 Minutes
Vibration Frequency: 1,780 c.p.m.
Vibration Stroke: 11mm
Impact Stroke: 19mm
Structure Acceleration: 19.5G


CoiLok successfully passed the NASM1312-7 test as well as exceededing the requirements of 17 minute test by more than 600% by running the test for 1 hour 42 minutes showing no signs of loosening and total security! The data from these tests prove that the CoiLok™ secured nuts maintain stable locking and resist loosening – regardless of the severe impact to which they are exposed.

A performance comparison with other lock nut and lock washer solutions on the market demonstrates the clear superiority of CoiLok™ for vibration resistance and prevention of unwanted loosening.

NAS 3350
NASM 1312-7



  • •HDG 10270-1 Steel / Stainless Steel
  • •Reusable
  • •Corrosion resistant
  • •Impact Shock & Vibration resistant
  • •Coarse threading only
  • •For bolted joints only
  • •Coarse threading
  • •Minimum of 4 bolt threads protruding past nut.

Other sizes and materials available by request.

    •Materials: Other steels, Inconel. •Plating/Coating: Oil or Phosphate, HDG, Black, Oxide, Zinc and more.

CoiLok™ Quick Tool

• Included with large volume orders.*
• Available for order separately
• Materials: Carbon Steel
• Plating: Zinc

*Contact your distributor or LIMIT Lock Ltd. for more information or to get a user guide.


CoiLok™ can be installed and removed easily by a number of ways.

Low volume assembly: Hand tightening and removal is simple. For even greater ease a thin metal tool like a screw driver can be used. For mid-level and high level volume, the purpose built CoiLok™ Quick Tool can be used  for both assembly and disassembly

For more comprehensive information, refer to the 'How To Use CoiLok™' guide available on request or from your distributor.

The CoiLok™ tightening torque is under 1Nm. Correct force and installation is determined easily and visually or is automatically controlled when using the CoiLok™ Quick Tool.

Stainless Steel: When tightened and loosened correctly, 2-3 cycles of reusability can be achieved. Carbon Steel: When tightened and loosened correctly 5+ cycles are possible, for sizes M16 or 5/18" and larger 15+ cycles are possible.

Before reuse, the CoiLok™ should be physically inspected for deformity.  If deformed, the CoiLok™ should not be reused.

Four threads is the recommended minimum. For sizes smaller than M10, three is the minimum.

The CoiLok™ will work with industry standard bolting lubricant or anti seize. For more information, feel free to consult with a CoiLok™ distributor or specialist.

In general, CoiLok™ can be used effectively wherever the corresponding material of fastener performs well.  For very high or low temperature applications, consult with a CoiLok™ distributor or specialist before ordering to ensure correct material and/or plating is being used. For more information, refer to the 'How To Use CoiLok™ Guide'.