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Seventy years ago Louis C. Huck – the founder of Huck Fasteners, which ultimately became part of AFSR – was approached by the US Navy and the railcar market to produce a vibration resistant fastening element. The solution he created was the original Huck lockbolt.

The original Huck lockbolt was developed as an alternative to the conventional bolt and nut combinations, which exhibited some severe weaknesses. These included loss of preload under service load; setting and relaxation effects in thread; self-loosening effects under vibration load; and relative movement in the thread bearing area.

The traditional Huck lockbolt was able to combat these problems and consistently provide a secure locking system. For instance, the lockbolt has a special locking groove design that provides vibration resistance and extreme fatigue life. This is due to a larger cross-sectional area and no stress concentration. When compared, a 16mm lockbolt has 18% more bolt cross sectional area than a M16 IS0 or EN screw standards bolt. Lockbolts also have a larger core diameter than regular bolts.

When it comes to the self-loosening effect under vibration load we are all aware of the Junker test, which monitors a bolted joint as it loses its preload when subjected to shear loading caused by transverse vibration. Compared to conventional bolts and nuts, lockbolts demonstrate superior vibration resistance. They have no relative movement in the thread bearing area. There is also no need for washers when using a lockbolt. Predominately in civil engineering a conventional bolt needs washers on both sides to protect the surface from damage caused by the rotation of the nut when torqued. With a Huck lockbolt there is no need for a washer, as a lockbolt is simply an axial installation. In addition, when users install conventional bolts on sloped surfaces they need a sloped washer and there is a good chance there will be misalignment. Again, with a Huck lockbolt there is no need for such a washer and there is no misalignment – thanks to the Huck lockbolt’s ‘collar’ design.

Huck lockbolt technology works on a different principle to regular bolting, where instead of a threaded nut, a cylindrical ‘collar’ with a smooth internal bore is used. The collar is placed over a pin with locking grooves that either follow the form of annular grooves or a special form helical thread. During installation this collar is ‘swaged’ permanently.

This joining process offers a number of significant advantages over regular bolting. The joint is maintenance free as once the collar is ‘swaged’, it will not loosen under vibration. This provides major savings in labour costs by eliminating the need to re-torque bolts periodically in order to ensure joint integrity. The major safety benefit is that the joint is guaranteed to maintain clamp and not become compromised over time.

Over the years the Huck lockbolt fastener has evolved. The traditional lockbolt has advanced all the way to an innovative lockbolts without pintail – such as the Huck BobTail® system.

Launched in 2009, the BobTail fastener has been successfully used in a variety of industrial applications. It offers up to 10 times the fatigue strength of conventional nuts and bolts, and delivers ultimate strength, installation speed, and vibration resistance.

The BobTail lockbolt was designed to provide superior joining strength and offers fast and secure installation. Through its advanced fastener design, as well as using the latest easy-to-use ergonomic installation tooling, the BobTail system offers a strong connection. In addition the pintail-less design of the BobTail means that there is a reduction in noise during installation; there is no waste through breaking of the pin; and there is an improvement in corrosion resistance by eliminating the exposed surface resulting from the pintail break.

The recently developed Huck 360 system is a special system that works like a lockbolt, but with a unique tightening installation process. At first sight, the Huck 360 system looks very much like a conventional threaded bolt and nut combination. However, there are very significant technical and even more significant performance differences.

The Huck 360 has a shallow proprietary thread form that concentrates 27% less axial stress in the root than conventional bolt threads. This stress concentration area is the primary contributing factory leading to stress corrosion cracking and fatigue failures. Huck 360 lockbolt’s thread flanks are effectively locked preventing the nut from moving relative to the bolt – in contrast to a conventional threaded bolt where thread flanks are able to slide when subjected to transverse vibration, resulting in the nut moving relative to the bolt.

Additonally, when the Huck 360 lockbolt nut is tightened, it plastically deforms around the thread. This results in a very close circumferential contact when tightened, helping to generate vibration resistance previously only achievable by using a traditional lockbolt. The Huck 360 lockbolt is also available in steel up to Grade 10.9, which is unique in the market.

These innovative fastening solutions underline AFSR’s commitment to helping our customers with their challenges. We are always focusing on what the market needs and how we can help solve assembly issues. By developing our lockbolt capabilities we are helping users solve problems in applications – no torque, easier evaluation, maintenance free, and high corrosion standards.


The Arconic product range currently offers the greatest breadth and depth of fastening solutions available including: self-locking nuts, quick-release fasteners, draw latches, threaded inserts, lock-bolts & structural blind fasteners.

Arconic is built on an extraordinary heritage of innovation that began with Alcoa’s founding in 1888. Our businesses have helped shape the aerospace, automotive and building and construction industries since the days of the Wright brothers and Henry Ford, and the first modern downtowns.

On November 1, 2016, Arconic launched as a global leader in multi-material, precision-engineered products and solutions for high-growth markets, following our successful separation from Alcoa’s bauxite, alumina and aluminium products units.

Through decades of experience working closely with major manufacturers from a myriad of markets, Arconic has developed the capability to engineer and produce special parts to meet specific fastening requirements. We have successfully worked with some of the world’s leading manufacturers to develop unique and cost-effective solutions to fastening problems. With manufacturing and distribution facilities on all major continents Arconic has extensive experience working with customers on a global scale as well as providing for the fastening needs of local manufacturers. Global experience combined with Arconic’s long-standing leadership and ‘commitment to excellence’ make Arconic the best choice for fastening systems.

Arconic Fastening Systems and Rings’ brands include:

Huck –

Huck’s product line features an extensive collection of:

Huck LockBolts

Structural Blind Fasteners

Pneumatic and Hydraulic Tooling Systems including Power Rigs

Huck LockBolts and structural blind fasteners are designed to provide permanent, vibration-resistant, superior-quality joining solutions for use in industrial applications.

Marson –

Marson’s product line features an extensive collection of:

Non-structural blind rivets

Rivet Nuts

Tooling Systems

The Marson brand offers a full line of blind rivets in a wide variety of materials. Products include standard Open-End rivets and specialty rivets, including Closed-End, Multi-Grip and Plastic rivets.

Camloc –

Camloc’s product line features an extensive collection of:

Quick Release Fasteners

Draw Latches

Solid Inserts/Keenserts®




Captive Solutions

Customised Solutions

The range of quick release fasteners, draw latches & solid inserts from Camloc brings together 70 years worth of experience, traditional engineering skill and innovation, providing customers with effective, reliable and creative solutions for applications in electronics, industrial, transportation, aerospace and defence markets.

Recoil –

Recoil’s product line features an extensive collection of:

Precision wire thread inserts

High quality taps

Versatile tooling

Thread repair kits

Complementary thread repair products

Recoil’s range of quality wire thread inserts enable you to produce strong, permanent threads in metals and plastics but are particularly useful for creating strong threads in softer materials such as aluminium, titanium and magnesium alloys.

Simmonds –

Simmonds Self-Locking Nuts

Cold forging and Screw Machining

Value Range – Cage Nuts, Flange Nuts, Nylstop Nuts, Weld Nuts and Washer Nuts

Stainless Steel Screws

In recent years, Simmonds has continued to develop this expertise and capability in high specification female thread fastener solutions which enables us to make high precision bespoke nuts to meet the specific quality, performance and cost requirements of our customers.


Single and double slotted self-locking nuts (Network Rail certified)

Special nuts

Drawing parts

SNEP products are commonly used in a wide variety of differing industries and markets and are so versatile they can be used in applications ranging from automotive to green energy and from aerospace to rail-track.

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