HARDLOCK Nuts, Securing Against Vibration

The most secure fastener for extreme vibration environments.

01.

Anti-vibration performance

02.

Unique wedge-locking principle

03.

Reduced maintenance

04.

Built for demanding applications

How does it work?

The Hardlock Nut utilises the wedge principle to create a powerful self-locking force.

Forcing a wedge into the gap between a cylinder and its surrounding tube makes it possible to create a powerfully locked assembly.

Creating matching key grooves in both the nut and bolt, and then using a hammer to drive a wedge into those grooves does provide a powerful self-locking effect. However, this method is unsatisfactory from the standpoint of operability.

The solution is to use two nuts to play the roles of the hammer and wedge respectively. A small eccentricity in the sliding part of the convex top of the lower nut acts as the wedge. When the concave upper nut is tightened, the effect is exactly the same as that produced by a hammer driving in a wedge. It is much more effective to use a screw as this makes it very easy to force the wedge into place.

After tightening the lower nut (1), install and tighten the upper nut (2) by hand. At this time, a gap is created. This is a tightening margin used to provide the self-locking effect.

*During installation, installing the nuts in the opposite order to that shown above, i.e., installing concave nut (2) first and then tightening the convex nut 1, results in exactly the same self-locking effect.

Tightening the upper nut (2) with a wrench generates torque, which allows the self-locking effect to be felt by hand. Make use of this feedback to set the torque value as required. At this time, the powerful self-locking effect is intrinsic, regardless of whether or not there are any gaps between the upper and lower nuts, so you can rest assured that the nut is securely tightened.

Hardlock Fishplate Installation Demo

In this video we demonstrate Staytite Rail’s recommended method for fitting a fishplate using a metric conversion kit and Hardlock Industry Nuts.

The most secure fastener for extreme vibration environments.

Superior Vibration Resistance

The Hardlock Nut resists loosening from vibration longer than any other fastener or locking nut on the market.

A leading choice for engineers in Japan, America, the United Kingdom and Europe, the Hardlock Nut uses a unique wedge principle to create an unprecedented and powerful self-locking force.

Proven Across Industries

Hardlock Nuts have been successfully deployed in many applications worldwide for more than a decade.

They are used across industries including railways, automotive, civil engineering, telecommunications, radar, power masts, towers and pylons, wind turbines and masts, to name but a few.

Proven Performance

DIN 65151 vibration tests demonstrate how Hardlock Nuts outperform other nuts in the fastener market today.

Test data is also available upon request, just use our contact page for more information. At Staytite, we hold large stocks of Hardlock Nuts in various sizes, materials and finishes to meet your requirements.

Network Rail Certificate of Acceptance

PA05/02077 – Hardlock Nuts

Staytite Hardlock Nuts are covered by Network Rail Certificate of Acceptance PA05/02077, supporting approved rail fastening applications where connection security and vibration resistance are critical.

At Staytite we hold large stocks of Hardlock Nuts in various sizes, materials and finishes to meet your requirements.

Click the link below to access the certificate documentation:

What does a modern approach to fishplate installation look like?

Modernising fishplate installation with reliable fastening technology

A NEW APPROACH

Fishplates have traditionally used imperial bolts, nylon insert fasteners and black grease.

There are a few practical problems with this approach.

The joint needs to be opened periodically when the lubricant needs replacing. Traditional locking methods, such as nylon insert fasteners, can lose performance with repeated use and may be more susceptible to loosening under vibration.

ACCESSIBLE METHODS

Hardlock Nuts provide a mechanical locking system designed to resist loosening from vibration and other external forces.

Black grease can also obscure the fishplate during visual inspection. While not shown in this video, Interflon Lube EP provides an alternative to traditional black grease.

It allows the fishplate to remain visible for inspection and can be applied by spraying over the exposed joint rather than opening the joint.

REUSABLE PERFORMANCE

Metric bolts provide an accessible alternative to imperial arrangements. Hardlock Nuts work on a wedge-like principle, so they can be reused multiple times without loss of performance.

Testing has demonstrated successful installation and removal for 51 cycles, supporting their suitability for applications where components may need to be removed and refitted.

Data is available on request, for more information visit our contact page.

For more information about our Hardlock Nuts, call us at 0300 373 9029 or contact us at our email address: rail@staytite.com