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Finding the perfect solution for you starts with a conversation. Reach out today and we will reply in a timely manner.

icon_widget_image 999 Forest Edge Drive Vernon Hills, IL 60061 icon_widget_image (847) 970-4050 icon_widget_image sales@securitylocknut.com

Products & Solutions


Solving bolted joint problems is what we do.

Our engineers have extensive experience analyzing and solving bolted joint problems on a wide variety of applications. We will work with you to resolve your situation whether or not it involves using our locknut.

We work with industry leaders in railroads, mining, material handling, crushing & pulverizing, and more to identify issues and offer products and ideas specific to their needs.

The Original Security Locknut

Proven performance on the world’s most demanding applications.

Available in a wide variety of sizes and styles

(Inch series, Metric series, Hex, Square, thin, plated)

Custom Shapes & Sizes

We do that!

Non-locking Nuts

We make these too!

Available in all the same sizes and styles as our Security Locknut products

Spherical Washers

For use when bolting to surfaces that are unpredictable and non-parallel.

These washer sets will provide an even clamp surface to eliminate bending stress and help retain bolt tension.


Available in common sizes – call for details

Flat Washers

Used to protect the joint surface from damage during tightening and distribute the load under the bolt and nut head.

Available in common sizes – call for details

The Mill Hero

  • Fully integrated one-piece design features a Security Locknut, Washer, and Rubber Seal. Easy to handle, fast to install, and reusable.
  • Primarily designed for use on grinding mills in mining operations. This reusable product holds the mill liners secure and seals the through-hole to prevent leaking.

Bolts & Kits with Combined Parts

Working with our partner suppliers to provide bolts and externally threaded fasteners to our customers. Kit packed per your handing requirements.

Call for details.

Why Do More Engineers Choose Security Locknut?

Simple & effective all-steel construction

Requires no special tools for installation

Vibration-resistant “won’t back off”

Reusable and infinitely adjustable

Does not damage or deform the bolt thread

Proven for decades in the most demanding applications

Holds in any position on the bolt

Performs at extreme temperatures

Performs in extreme environments

Fast – Popular sizes in stock and ready to ship

Customized locknuts for your unique equipment

How it Works

The Patent

The key to Security Locknut’s performance is in the spring-steel lock ring. While other’s have tried to imitate our design, no other solution on the market comes close to our performance because of the unique way in which our spring-steel lock ring is engineered & manufactured. The amazing technology behind our spring-steel lock ring results in incredible rotational resistance for securing the locknut, while at the same time allows for ease of installation. The ring material is based on a durable spring steel alloy which doesn’t distort the threads of the bolt. This means repeatable performance even after the locknut has been removed and reinstalled dozens of times.

How it Works

Vibration Testing

Vibration testing using the NASM 1312-7 protocol. This standard that establishes a procedure for conducting accelerated vibration tests on any fastener system capable of providing a clamp-up load. The bolt/nut combination is installed in the fixture, the fixture is subjected to controlled vibration and times/cycles until the assembly loosens. The Security Locknut performed exceptionally well in tests against other commonly used products.  A summary of the test results are shown below.

Product Cycles to loosen Cycles to fall completely off
Security Locknut 55,000 Never **
Nylon Locknut 15,000 25,000
Conical (or Top lock) Locknut 2,000 6,000
Standard + split washer 100 500
* * Test stopped after 90,000 cycles 

Proven performance on the world’s most demanding applications.

Available in a wide variety of sizes and styles

(Inch series, Metric series, Hex, Square, thin, plated)