The Definitive Guide to Tamper-Proof Nuts, Screws and Bolts

Tue 18th Nov 2025

Introduction

Protecting assets from theft, tampering and vandalism remains just as crucial today as it’s always been. Staggeringly, metal and cable theft cost the UK economy nearly £480 million in 2022, and an estimated £4.3 billion since 2013. [1] From rail networks and transport hubs to electrical installations and public infrastructure, one of the most effective ways to safeguard equipment is through specialised tamper-proof nuts and bolts (tamper-resistant screws). This guide will take you through everything you need to know about tamper-proof nuts, security bolts and other anti-tamper screws. We’ll cover their types, applications, security ratings, installation best practices and even the sustainability benefits they bring to long-term projects. By the end, you’ll understand how to select and install the right fasteners for your needs, keeping your assets secure and compliant.

Throughout this blog, we place a particular focus on Hafren Security Fasteners. E-Tech Components are now an Authorised Distributor for Hafren Fasteners who are the UK’s leading name in security and tamper-resistant fasteners. We supply their Kinmar® Permanent and Removable Nuts as well as their 6-Lobe Pin and Pin Hex Fasteners.

What are Security Fasteners and Their Types?

Security Fasteners are specially designed screws, bolts, and nuts that prevent unauthorised access, tampering and theft. Unlike standard fasteners, they feature unique drive heads or patented designs that require specialised tools for installation and removal. Common examples include Tamper-Resistant Screws, which use unconventional drive heads such as pin hex or one-way designs to make removal difficult without the correct tools.

Then there’s Security Bolts, which often feature breakaway or shear heads that cannot be easily removed once tightened; and Tamper-Proof Nuts, which require specific tools for removal and provide a high level of protection against unauthorised interference. Hafren’s Kinmar® Permanent and Removable Nuts are ideal examples of these. One-Way Fasteners are another option, designed to be installed easily but nearly impossible to remove without causing damage, adding an additional layer of deterrence.

Industries and Applications

Security fasteners are used across a wide range of industries, from public infrastructure and transportation to government facilities, retail and electronics. Hafren Security Fasteners are trusted worldwide for projects that require high-security and durability. Common applications include airports, rail stations, data centres, fencing, signage, streets, parks, playgrounds, prisons, regeneration projects, stadiums and other public venues. By incorporating tamper-proof nuts, tamper-resistant bolts and anti-tamper screws into their assemblies, businesses can significantly strengthen the physical security of their assets.

Choosing the Right Tamper-Proof Nuts and Bolts

Selecting the correct fastener depends entirely on the application and the level of security required. Hafren Security Fasteners have simplified this decision with a 1-to-5 security rating system, helping you choose the right solution. Selecting the appropriate security level ensures that the fastener provides adequate protection without compromising functionality or maintenance needs.

Understanding Security Ratings

Security ratings hinge on removability and tool accessibility. Understanding the distinction ensures the right balance between security and operational flexibility.

Best Practices for Installing Tamper-Proof Nuts and Bolts

Even the strongest tamper-proof nuts and bolts can fail if installed incorrectly. Key practices include:

Advantages of Tamper-Proof Nuts and Bolts

Using tamper-proof nuts and bolts (tamper-resistant bolts) and anti-tamper screws offers a range of benefits that go beyond basic security. They provide protection by deterring theft, tampering and vandalism, and enhance safety by reducing the risk of accidents in sensitive environments such as electrical panels. They also improve operational efficiency, helping to minimise downtime and maintenance costs. Many designs offer flexibility, allowing for removal during servicing without compromising the overall security of the installation. Finally, they deliver exceptional durability. Hafren products, including their Kinmar® Nuts, Pin Hex and 6-Lobe Pin Fasteners, are specifically engineered to perform reliably in harsh conditions and over extended periods of use.

Security Fasteners and Sustainability

High-quality fasteners play an important role in supporting sustainable infrastructure. Their durability helps reduce waste by extending the lifespan of installations and minimising the need for frequent replacements. They also lower maintenance costs and environmental impact, as fewer site visits translate into reduced fuel consumption and carbon emissions. Additionally, many are made from recyclable materials such as stainless steel and coated alloys, offering long-lasting, eco-friendly performance. For instance, public transport authorities have successfully reduced maintenance cycles and operational costs by upgrading to Hafren tamper-proof nuts and bolts. This choice strengthens both their security measures and their sustainability objectives simultaneously.

Our Hafren Range of Tamper-Proof Nuts & Bolts

Kinmar® Permanent Nuts

	Hafren KMPN-S A2 Stainless Steel Kinmar ® Permanent Nuts They require a matching driver socket for installation, ensuring accurate torque levels and allowing for re-torquing if needed. Not governed by shear point and leaving no unplated surfaces, they leave a clean smart finish.
	Hafren KMPN-Z Case Hardened Steel Bright Zinc Plated Kinmar ® Permanent Nuts They require a matching driver socket for installation, ensuring guaranteed torque levels and allowing for re-torquing if needed. Unlike traditional shear nuts, these Zinc Plated Kinmar Nuts leave no unplated surfaces, resulting in a clean, professional finish.
	Hafren KMPN-GEO Case Hardened Steel Geomet ® Kinmar ® Permanent Nuts They require a matching driver socket for installation, ensuring consistent torque levels and allowing re-torquing if needed. Unlike standard shear nuts, these Steel Geomet Kinmar Nuts provide full surface protection with no exposed metal, leaving a clean, professional finish.
	Hafren KMPM-Z Case Hardened Steel Bright Zinc Plated Kinmar ® Permanent Bolts They require a matching driver socket for installation, ensuring guaranteed torque levels and allowing for re-torquing if needed. Unlike traditional shear bolts, these tamper-resistant bolts leave no unplated surfaces, providing a clean, professional finish ideal for high-security applications.
	Hafren KMPM-GEO Case Hardened Steel Geomet ® Kinmar ® Permanent Bolts They require a matching driver socket for installation, ensuring guaranteed torque levels and allowing for re-torquing if needed. Unlike traditional shear bolts, these tamper-resistant bolts leave no unplated surfaces, providing a clean, professional finish ideal for high-security applications.

Kinmar® Removable Nuts

	Hafren KMRN-S A2 Stainless Steel Kinmar ® Removable Nuts They offer outstanding resistance to tampering, combining strength, reusability and a smooth finish. Ideal for a wide range of applications, these Stainless Steel Nuts deliver long-lasting corrosion resistance.
	Hafren KMRN-Z Case Hardened Steel Bright Zinc Plated Kinmar ® Removable Nuts They feature a unique segment-shaped profile that requires a matching driver socket for installation and removal. This ensures maximum security and convenience. These Zinc Plated Kinmar Removable Nuts offer a smooth, professional appearance with no unplated surfaces, providing both functionality and visual appeal.
	Hafren KMRN-GEO Case Hardened Steel Geomet ® Kinmar ® Removable Nuts They require a matching driver socket for both installation and removal. This provides a precise, torque-controlled fit while maintaining exceptional resistance to tampering or forced attack. The Geomet ® coating offers outstanding corrosion protection and a clean, professional finish ideal for both indoor and outdoor high-security applications.
	Hafren KMRM-Z Case Hardened Steel Bright Zinc Plated Kinmar ® Removable Bolts They require a matching driver socket for both installation and removal. This ensures precise torque control while maintaining exceptional resistance to tampering or forced attack. Unlike traditional bolts, these tamper-resistant bolts leave no unplated surfaces, providing a clean, professional finish suitable for high-security applications.
	Hafren KMRM-GEO Case Hardened Steel Geomet ® Kinmar ® Removable Bolts They require a matching driver socket for installation and removal. This ensures guaranteed torque levels while allowing for versatile, cost-effective use. Unlike traditional shear bolts, these tamper-resistant bolts leave no unplated surfaces, providing a clean, professional finish suitable for high-security and aesthetic-sensitive applications.

6-Lobe Pins

	Hafren RTBS Button Head 6-Lobe Pin Self Tappers They feature an internal pin recess, allowing quick and secure installation and removal using the matching driver tool. Ideal for high torque applications, these A2 Stainless Steel anti-tamper screws are durable, versatile, and cost-effective. They provide a clean, professional finish for both security and aesthetic-sensitive projects.
	Hafren RTCS Countersunk 6-Lobe Pin Self Tappers They feature a 6-lobe recess with an internal pin, ensuring secure fastening while preventing tampering. Quickly and easily installed and removed using matching tooling, these A2 Stainless Steel tamper-resistant screws provide reliable performance across a wide range of applications.
	Hafren RTBM Button Head 6-Lobe Pin Machine Screws These anti-tamper screws feature a 6-Lobe recess with an internal pin. They have a matching driver socket for quick and reliable installation and removal. These A2 Stainless Steel tamper-resistant screws deliver excellent corrosion resistance and a clean, professional finish suitable for high-security and precision assemblies.
	Hafren RTCM Countersunk 6-Lobe Pin Machine Screws Manufactured from high-quality A2 Stainless Steel, these screws feature a 6-Lobe recess with a central security pin. This offers an ideal combination of durability, security and corrosion resistance. The countersunk head ensures a flush, professional finish, making these tamper-resistant screws suitable for a wide range of safety-critical and aesthetic applications.
	Hafren RTRM Raised Countersunk 6-Lobe Pin Machine Screws They feature a 6-Lobe recess with an internal pin, providing a secure, tamper-resistant drive for high torque installation. Quickly and easily installed or removed using the matching driver tooling, these tamper-resistant screws deliver reliable performance and a professional finish.

Pin Hex

	Hafren PHBS Button Head Pin Hex Self Tappers These anti-tamper screws ensure that medium torque applications are secure. They are one of the most difficult-to-remove fasteners without the matching driver. Their button head design provides a smooth, professional finish ideal for industrial and commercial applications.
	Hafren PHCS Countersunk A2 Stainless Steel Pin Hex Self Tappers Manufactured from durable A2 Stainless Steel, these screws feature an internal pin hex drive that prevents removal with standard tools. This provides a strong deterrent against tampering and vandalism. The precision-engineered design ensures a clean countersunk finish, making Hafren PHCS Self Tappers ideal for applications where both security and appearance matter.
	Hafren PHBM Pin Hex Button Head Metric Machine Screws These screws offer secure fastening and exceptional resistance to tampering, as they cannot be removed using standard hex tools. Ideal for medium torque applications, these tamper-resistant screws offer a professional finish and long-lasting performance in both commercial and industrial settings.
	Hafren PHCM Countersunk Pin Hex Machine Screws They cannot be removed with standard hex tools, ensuring secure fastening and high tamper resistance in medium-torque applications. Unlike standard countersunk screws, these A2 Stainless Steel tamper-resistant screws provide a clean, corrosion-resistant finish.
	Hafren PHRM Raised Countersunk Pin Hex Machine Screws These anti-tamper screws feature an internal pin that prevents removal using standard hexagon tools. This makes them ideal for medium torque applications where security and integrity are critical. The raised countersunk design ensures a neat, professional finish while offering excellent tamper resistance.

E-Tech Components are proud to be an Authorised Distributor of Hafren Security Fasteners, providing customers with expert technical support, premium products and tailored solutions. Our team offers specialist guidance to help you select the right tamper-proof nuts and bolts for your specific application. We supply high-quality, patented fasteners engineered for maximum durability and tamper resistance. This includes Hafren’s Kinmar® Permanent and Removable Nuts, as well as Pin Hex and 6-Lobe Pin Fasteners. For projects with unique specifications, we also offer bespoke solutions, such as custom lengths, finishes and specialised designs. By partnering with E-Tech Components, you can be confident that your installations are secure, compliant and backed by industry-leading expertise.

Frequently Asked Questions

Are Security Fasteners Removable?

Yes, depending on the type, Some are permanent 1-way fasteners, while others are removable with the correct tooling.

Can Security Fasteners Be Used Outdoors?

Yes. Many fasteners are made from corrosion-resistant stainless steel suitable for harsh conditions.

Are Tamper-Proof Fasteners Fire-Resistant?

Materials like stainless steel withstand high temperatures, while compliance with standards ensures safe performance.

How Do I Maintain Security Fasteners?

Regular inspections, cleaning and torque checks are recommended to maintain integrity.

Conclusion

Tamper-proof nuts and tamper-resistant bolts are essential for safeguarding modern infrastructure. They protect assets, enhance safety, reduce maintenance costs and contribute to sustainable practices. By choosing the right security fasteners and working with E-Tech Components, you can ensure your projects are secure, reliable and future-proof.

References

1. Tackling Metal Theft: A report by the All-Party Parliamentary Group on Metal, Stone and Heritage Crime