What is a structural rivet?

Ultimate Guide To Structural Rivets.  

High strength structural rivet is ideal when seeking a super strong vibration resistant solution. They are commonly used in heavy duty applications such as the fabrication of utility vehicles, trucks, trains, truck trailers, security fencing and numerous other applications. Structural rivets are commonly referred to as Huck rivets, lock rivets or Monobolt® and their industrial clamping strength comes from the unique combination of internal pin retention & locking mechanism that creates their inner strength. In this blog we will cover the range of structural rivets providing an overview of these industrial strength rivets, and the right rivet guns plus some lab rivet testing results to assist in rivet type selection.   

Rivets are a popular fastener to join two or more pieces of material. Essentially a rivet is composed of two components, a metal tube (body) & pin (mandrel). The pin is normally longer than the body and designed to be pulled up through the tube whilst enlarging it in the process and clamping the material. See image on the right showing the anatomy of a typical structural rivet.

Typical Structural Rivet

This results in the enlarged body clamping the material between the two ends of the tube. There are numerous rivet types for virtually any application; from connecting your home’s guttering through to the cars we drive and the planes we fly. In fact, it is almost impossible to imagine today’s world without rivets. Aerobolt has the complete range of structural rivets & standard rivets categories to assist in your application. 

What are the main structural rivets types?

There are three different type of structural rivets. Listed here is an overview of rivet labels and grouped accordingly.    

1. Multi-Grip Structural Rivets. (Huck Rivet Magna-LokHucklok®,  Monobolt®)

Huck Magna-Lok® is a versatile structural rivets that is ideal for multiple material grip ranges. This rivet has Huck’s unique internal locking mechanism that provides a high resistance to vibration & moisture. Fast and easy to install using conventional Huck brand gun or a structural rivet gun. Aerobolt is Australia's number #1 Huck distributor with the complete range of structural rivets and structural rivet tools. 

2. Bulb Structural Rivets.( Allok Rivet, High Strength Rivet, Hemlok®, BOM, Orlock Rivet)

Allok structural rivets feature a double-locking system that secures the material on both sides of the panel for great strength, providing a vibration and weather resistant joint. It has a non-protruding blind side bulb that spreads the load, whilst avoiding pull-through. Easy to install via a Huck gun & other structural rivet tools as a standard rivet gun is not built to install structural rivets. Also known as Orlock rivets or Hemlok rivets.   

3. Tri-Folding Aluminum Structural Rivets. (Bulb-Tite, Huck-Tite, Tri-Bulb)

These rivets have a slot or split body that creates a propeller shape blind-side anchor making it ideal for lightweight applications. The Bulb-Tite® is a tri-folding rivet that spreads it's clamping force through the anchor blades and combines with a washer to provide a weatherproof joint. Great for fabricating with composite materials or where water might be an issue. Its shear and tensile strength is significantly less that the other two structural rivets.

How do structural rivets work?

Structural rivets work a little differently to a standard rivet, as there is an internal  mechanism that locks a portion of the pin (mandrel) inside the rivet's body. This creates an additional layer of material that assists in increasing the rivets  strength, whilst interlocking with the material and creating their inner strength.  

When installing a structural rivet the body changes in one of the following ways as it interlocks itself into place. 

1. Broadening of the Body (Multi-Grip Structural Rivet)

Body widens when the cap of the pin is pulled up, resulting in the body expanding against the material.

2. Body Compresses & Bulges (Bulb Structural Rivet)

Rivet's body is compressed by the pin cap, causing it to bulge and form a bulb against the material.

3. Body Splits & Folds (Tri-Fold Split Structural Rivet)

The slotted body folds and splits into a  propeller shape blind–side anchor, ideal for lightweight material.   

What are the advantages of a Structural Rivet?

Renowned for their strength and being a superior option compared to most other fasteners, key advantages include:

  • One side assembly for fast installations as access to the rear is not required.
  • Super strong, forming a mechanically activated permanent joining solution.  
  • Vibration and weather resistant. Offering high shear & tensile strength.
  • Easy to use air, cordless, air and manual tools that are rugged & robust.  
  • Design flexibility, wide range of types, material, etc. to suit most applications.   
  • Easy inspection and maintenance, no expensive equipment for quality control.  

How do you install a structural rivet? 

Installation of a structural rivet is similar to pulling up a standard rivet, however you will require a special tool, as a structural rivet needs a Huck gun or a structural rivet gun for a successful installation. Standard rivet guns are not equipped to install these special type of rivets.

To install a structural rivet, pre drilling of holes is required. Load rivet’s pin tail section into rivet gun. Insert rivets body into hole and activate gun. Upon activation the head of the rivet is pushed against the nose of the tool, whilst the tool pulls up the central pin. As a result, the body compresses, and expands on the blind side until it maxes out to approximately one and a half times the size of the original diameter. Resulting in a larger surface in which the two materials are effectively fastened together.

How to install a Structural Rivet

Which is the best structural rivet gun?  

Selecting the correct rivet gun depends on the nature of the project + your specific requirements, below we cover the main rivet gun categories, along with their pros. & cons. At Aerobolt, we stock a wide range of popular brand rivet guns plus a few alternative options that we have rivet gun lab tested for quality and value. Our site has extensive information covering most tools for you to review. To discuss further, simply contact us

Structural rivets guns are broken down to two main types

  1. Huck guns that install both structural rivets and Huck bolts (pin & collar).
  2. Rivet guns that install structural and or standard rivets. Note that not all rivet guns are capable of installing structural rivets. Here at  Aerobolt, we have both options. 

Huck Gun, air + cordless

Huck tools are suitable for the installation of both Huck bolts and Huck structural rivets with the simple changeover of a nose assembly (priced separately).

Air Huck Guns: For frequent installation, an air-powered Huck gun is the easiest choice for the job. Air powered Huck guns offer fast installations with consistent results. Some of the pros include: Easy to use, economical (cost saving compared to cordless), and no physical exertion required. They will also install to a set pressure / stroke. Cons: Requires an air source such as a compressor, possibly limiting mobility and making remote use impractical.

Cordless Battery Huck guns: Cordless Huck guns run on battery power and provide incredible versatility, allowing you to install Huck fasteners from practically anywhere. Like air tools, battery-powered tools are basically point-and-shoot. Pros: Mobility, speed. Cons: Batteries have limited charge before needing to be plugged in again, cost.

Rivet Guns, air + cordless

These guns are suitable for the installation of both structural and standard rivets, i.e. they do not install pin and collar Huck Bolts. They do not require a separate nose assembly and are generally an economical alternative to a Huck gun.  

Air Rivet Guns: For frequent rivet installation, an air-powered riveter is the easiest choice for the job. Air rivet guns offer fast installations with consistent results. Some of the pros include: Easy to use, economical (cost saving compared to cordless), and no physical exertion required. They will also install to a set pressure / stroke. Cons: Requires an air source such as a compressor, possibly limiting mobility and making remote use impractical.

Cordless Battery Rivet Guns: Cordless structural rivet guns run on battery power and provide incredible versatility, allowing you to install rivets from practically anywhere. Like air tools, battery-powered tools are basically point-and-shoot. Pros: Mobility, speed. Cons: Batteries have limited charge before needing to be plugged in again, cost.

Manual Structural Rivet Tool. 

For the occasional installation of structural rivets, a manual riveter like the RT-33 (picture on the right) might be the most cost-effective option. Hand rivet tool work by adding the rivet to the end of the tool, squeezing the handles, and retracting the tool from the now applied rivet. Some of the pros include: Inexpensive, easy to use, great for the handy person. Cons: They require physical force.

Manual Rivet Tool

    What's the difference between Monobolt® and  Magna-Lok® rivet?

    Both Monobolt® and Magna-Lok® are popular multi-grip structural rivets that share many physical similarities however their longevity is the key difference. In laboratory rivet tests, the Huck Magna-Lok® rivet has outlasted the Avdel® Monobolt® by 20 to 1. Magna-Lok rivet lasted 2 million cycles whilst the other lasted 100,000.  Another key difference is that Magna-Lok does not require a special nose tip to be installed correctly, unlike the Monobolt® which requires a special nose tip. Huck’s locking mechanism has been engineered into the rivet to eliminate tooling and operator error. Read more about how these rivet's lab results expose differences.

    How do I select the right structural rivet?

    When considering selection you will need to look at; materials, diameter (size), grip range, head style, and strength. Here we look into the important criteria to consider prior to making a final decision. 

    Materials.

    Ensure the rivet material is compatible with the material being joined to avoid galvanic corrosion. As a rule, avoid using aluminium and stainless steel together, we recommend keeping the metal material like for like for maximum life. Stainless with stainless, aluminium with aluminium, etc.

    Rivet material compatibility table

    Rivet Diameter & Hole Size.

    The size of the rivet diameter & the drill hole size is critical for success. If the rivets diameter is too small for its hole, then the gap may cause installation failure. Referring to the hole diameters before drilling is an easy way to avoid issues later.

    Material Grip Range.

    The material grip range refers to the material thickness or the depth the rivet can be effectively installed. For example, if two 1.5 mm plates/items need to be riveted, a blind rivet with a material grip range between 2- 5 mm is required. Best practice dictates that the middle grip range of a rivet should be used and not the minimum/maximum sizes. This assists in achieving correct shear and tensile strength whilst ensuring the longevity of the rivet. Please note that the grip range is not the length of the rivet as many people mistakenly believe the length is the amount of material the rivet will pull up.

    Structural rivet head type.

    The rivet head type assists in holding the material together and enhancing its appearances. Dome heads sit proudly above the material, whilst large flange or truss head is a shallower broader head profile & suited for thin or soft material items like thin steel sheeting. The countersunk option provides a flush neat finish subject to countersinking the hole, allowing the head to sit level with the surrounding material.

    Structural Rivet Head Types

    Frequently Asked Structural Rivet Questions.

    How does a structural rivet work?

    Below we illustrate how a rivet works. Essentially a rivet is a metal tube with a pin (mandrel) through it, upon installation the pin's head is shaped to expand the tube & lock up the material.

    How Rivets Work

    Which is the strongest structural rivet? 

    Structural rivet is the strongest rivet type on the market and Aerobolt has the complete Huck Rivet range including the original multi-grip rivet "Magna-Lok", the Huck Rivet "Magna-Bulb" with its superior strength and the hybrid of the two "Hucklok Rivet"One of the strongest structural rivet type is the the Huck Rivet "Magna-Bulb". For installation values, refer to the table below to compare a range of structural rivet's lab results. We have taken the guess work out of selection by providing lab rivet results, so you can purchase in confidence.

    STRUCTURAL RIVET TYPE -STEEL KEY LAB METRICS FOR RIVET DIA. 6.4MM (1/4")
    Shear Typ. (kN) Tensile Typ. (kN) Grip Range (mm)
    Magna-Lok® (HRDS-0806) 11.1 8.2 2.0 – 9.5
    Hucklok® (HKLP-R8-6) 15.6 8.5 2.0 – 9.5
    Magna-Bulb® (MBDS-0806) 16.0 8.9 5.8 – 7.8
    Allok® (ARDS-08145) 13.7 7.9 5.0 – 8.5

    Can I get coloured structural rivets?

    Yes, Aerobolt can assist with painted structural rivets. They cost a little extra compared to the mill (raw) finish and are available in a wide range of colours. Refer to the Colorbond®  colour chart for selection.  

    How do I remove a structural rivet?

    Rivet removal is straight forward with the right tools. This requires the destruction of the rivet, and the best method is to drill it. You will need, a drill, drill bit, long nose pliers, & safety accessories such as glasses and gloves.

    Steps: Use your safety glass & gloves before starting the drilling process. Place the drill bit against the rivets’ center pin and drill through the body at a low but steady speed. Once drilling is completed, pull the rivet off with your long nose pliers. 

    What’s the difference between Huck Bolt and Monobolt®?

    A Huck bolt is a two-piece fastener whilst a Monobolt® is a one-piece fastener.

    A Huck bolt is a two-part pin & collar assembly that becomes a single entity through a mechanical process. This occurs when a tool applies pressure to the collar and forces it into the grooves of the Huck bolt pin. This process is known as a swaging process or cold forging.

    A Monobolt® is a single fastener that installs like a standard rivet via a tool. Monobolt® is a trademark for fundamentally a structural rivet, a rivet is composed of two components, a metal tube (body) & pin (mandrel). The pin is normally longer than the tube and designed to be pulled up through the tube whilst enlarging it in the process. This results in the rivet clamping the material. 

    Does a Huck structural rivet have an advantage over a Huck bolt?

    A Huck bolt is cumbersome and time consuming to install compared to a Huck rivet. To install a Huck bolt you will need access to both sides of the application, whilst a rivet requires access to one side. However, to many people a Huck bolt has a much better appearance because of the neat head.   

    Why has my structural rivet failed?

    There are a couple of reasons your rivet has failed. The issue could be a dodgy rivet from a shifty supplier or an installation issue. Either way we offer a wide range of technical services to right the wrong, including rivet testing lab services. We have teamed up with a NATA approved lab, that undertakes laboratory rivet testing services. Should you have a rivet failure, let us know rivetlabel, size, and material depth so we can review your application or have your rivets sent to the NATA approved lab for laboratory rivet testing. 

    Do you deliver rivets throughout Australia?

    Yes, we can deliver Australia wide through our network team of courier companies. In Sydney we offer our customers same day delivery if you order before 10.00 am or delivery the next day. Deliveries to regional New South Wales or other major Australian cities such as Melbourne and Brisbane including regional South Eastern Australia are either next day delivery or within 2 days. We also send to New Zealand and Asia.  

    Structural Rivet Summary

    Structural rivets offer superior fastening capabilities for heavy-duty and light fabrication applications. A rivet in one form or another has been used by people for numerous centuries and it is hard to imagine a world without rivets. Rivets are everywhere from the metal roofing and guttering that protect our homes, to the air conditioners that make us more comfortable, to the cars we drive, the planes we fly, and the ships we sail.

    Wherever there is a joining application there is bound to be a rivet to suit. Rivets are the #1 fastener in endless applications. At the conclusion of this blog, it is evident that rivets play an important part of the fastener world and irrespective of the rivet type needed for your project, be assured that your project will end up as a successful one with the use of the correct rivet - call us on 02 9755 3747 or contact us for guidance.

    Copyright © 2022 Aerobolt Australia Pty Ltd. All rights reserved.