Fastener Technology

An Introduction to Hydrogen Embrittlement

Hydrogen Embrittlement

Hydrogen embrittlement is a permanent loss in ductility caused by introducing hydrogen into a metal fastener in combination with stress. A typical hydrogen embrittlement (HE) failure is a delayed failure and happens after assembly. An HE failure is caused when three requirements are fulfilled. These areas are (1) hydrogen induced, (2) stress applied, and (3) high hardness. Continue reading for more information about each area.

Hydrogen Induced

Hydrogen needs to be induced for an HE failure. This is most commonly induced in the electroplating process, but can also be introduced into the material through corrosion of the bolt.

Stress Applied

Once stress is applied to a bolt that has a significant amount of hydrogen trapped inside the molecular structure, it is a matter of time when the hydrogen collects in molecular void and that void will grow bigger until the fastener fails.

High Hardness

This is the easiest pillar of an HE failure to control in the HE failure spectrum. Industry standards dictate that anything 320 Vickers Hardness or higher needs stress relief and possible further special attention.

HE failures can be very dangerous because the failure is delayed after installation and is very sudden. Before a bolt with HE is installed, there is not a visual way to identify if HE is present.

Any fastener that meets the hardness criteria need special attention and care to avoid HE failures. Contact us at if you have any questions about HE and its causes.


Brandon Bouska
Application Engineer

March 16, 2018
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Should I Use Weld Nuts, Self-Clinching Nuts, or Blind Rivet Nuts?

assorted nuts & screws

The use of captive nuts is a great design opportunity for a variety of applications. These differing styles of nuts are captive because once installed, they become an integrated part of the assembly. Examples of captive nuts are weld nuts, self-clinching nuts and riveting nuts. For more information on the specific designs consider the technology of each one.

Weld Nuts

Weld nuts are welded to another piece of metal. These can be used instead of sheet metal screws in thin sheet metal applications. Weld nuts come in different sizes and shapes and require equipment to install. These types of nuts form the strongest bonds. They are not plated for corrosion protection as this would hinder the welding process; a subsequent plating process or painting would be required to protect the assembly from corrosion after welding is complete.

Weld Nut

Self-Clinching Nuts (swage nuts or insert nuts)

Self-clinching nuts are clinched or pressed into soft sheet metal. They come with several types of plating options and can be heat treated to provide more thread strength unlike its counterparts. Self-clinching nuts also require equipment to install.

Slef-Clinching Nut

Riveting Nuts (blind rivet nuts)

Riveting nuts are the quickest to install. The necessary tools to implement this nut design are also relatively less expensive. They are installed much like a blind rivet and can be fixed into blind holes unlike self-clinching nuts or weld nuts.

Riveting Nut

Captive Nuts Comparison Chart

Type Application Advantages Disadvantages Special Tool Required
Quick installation Inexpensive piece price Different plating options Different strength options Other Need access to both sides No plating options  Precise pre-drilling required Need special tooling to install Other
Weld Nut General X Strongest bond  X X X Yes → Welding machine $$
Sheet metal
Self-Clinching Nut Sheet metal X X X Strongest threads X X X Yes → Press $$$
Circuit boards
Blind Rivet Nut Sheet metal X X X X X Grip range limited Yes → Pneumatic tool $
Laminated materials

**Advantages and disadvantages are accurate for most catalog offerings of these nuts, exceptions may apply


Picking the right captive nut for your design can be difficult. Luckily, Bossard has an engineering team with decades of experience, ready to help you. Contact us at for more information.

Fadi Saliby
Technical Sales Director

March 02, 2018
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How to Use Lighting Industry Fasteners the Right Way

Lighting Industry Fasteners

The lighting industry benefits from modern advancements in the smallest details of engineered lighting components. Rivets and fasteners, as well as wire management products, help everyone with their lighting needs. Whether the requests are for residential electrical jobs or those industrial and institutional lighting projects, the industry is thriving with several options for each scenario.

Rivets and fasteners are a few components that offer creative solutions to many lighting necessities. Drive fasteners, mounting buttons, fastener plugs and push-in fasteners are all a part of successful lighting installations. They can ensure a successful installment of light fixtures with convenience in mind.

Wire management is another concept to be appreciated when stringing it all together. Cable clamps will be a beneficial factor in keeping wires and cables neat and organized. A variety of clips and clamps exist in the markets today that are customized for those very specific jobs at hand.

The lighting industry has come a long way in making the little things matter more. The technological benefits and enhanced features that have been implemented in the smaller aspects of lighting are making more lighting preferences possible.

Reach out to us at to see how Bossard can help you with your lighting fastener needs.

February 23, 2018
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Joining CFRP: Attachment Methods for bigHead® Fasteners

bigHead® Fasteners

Choosing the right method of attachment for bigHead® fasteners can literally make or break your application. With innovations in materials and processes daily, in a continuously growing industry, choosing the right technique is imperative. It all comes down to details.

When it comes to Carbon Fiber Reinforced Polymer (CFRP) and attaching fasteners there are a few methods to consider. Today, traditional adhesive bonding methods are still effectively used in many production environments.  However, we have new techniques currently in development which include lean bonding and pre-form mechanical fixing prior to molding.

The lean bonding solution utilizes a pre-applied dry film adhesive, induction heating and pressure to reduce bonding time dramatically. Bonding times well under a minute can be expected. As an alternative to the adhesive bonding methods, bigHead® fasteners can be attached to CFRP by stitching, tufting, over-laminating or clinching into the pre-formed material.

For a more practical application, outlined below are techniques for attaching fasteners into dry fiber pre-forms:

  • Over-laminated: Either with ply-drops/localized or overlay holes to accommodate for stud
  • Stitching/tufting: Fastener retained in place by stitching into pre-form
  • Pocket stitched: Like over-laminated, but with stitching around the fastener to secure inside “pocket”
  • Pre-coupled patch: Fiber patch pre-applied to fastener and incorporated into molding (can be attached by adhesive or stitching/tufting)
  • Clinched: Fastener with spiked protrusions that embed into the pre-form

If you have any questions about bigHead® fastener attachment techniques into preformed CFRP please contact us through

February 16, 2018
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The Benefits of Understanding Basic Fastener Finish Requirements

When designing a bolted joint, many engineers look to a library of current designed-in parts, which is a great practice and should always be the first step when selecting possible fastening components. Many times, a part gets selected based on the dimensions of the fastener and is chosen for that reason alone. If the fastener’s finish is overlooked, it could be outperforming its requirements with regards to the finish. Basic knowledge of plating and coating practices can help create cost effective designs.

In one example, a bolt already in one customer’s fastener library had a finish designed for a corrosive environment. The finish standard limited that particular finish to one applicator. Without a basic knowledge of finishes, it is difficult to understand the consequences of requiring a bolt to use such a restricted supply base. After reviewing the example application, a suggestion was made to change the finish on the fastener to a coating more readily available in the industry. This suggestion resulted in a cost savings of over $30,000 per year.

A basic understanding of any implemented coating could help reduce initial cost of the bolted joint and will help the designer create a cost-effective design.

For more information on how you can create a more cost-effective bolted joint design, contact us at


Brandon Bouska
Application Engineer

February 02, 2018
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Why Process Control is Important for Fasteners – Continued

It is not uncommon for fastener manufacturers to adopt an SOP (standard operating procedure) and perform final inspection of the product after it is completed.

Do you believe final inspection is the best detection method?

Not always. If the product was contracted out of the manufacturers facility for heat treatment, patch, coatings or sorting, many things can potentially happen when the product is shipped out for further processing that the manufacturer cannot control. Product may be damaged, mixed with other types of product, or missed critical processes such as heat treatment or baking requirements. At minimum, all containers received back from outside services should go through a thorough visual inspection, and the certifications received back from contractors should be reviewed, as it is important to understand them.

So how many processes are there to make a simple hardened hex head cap screw with a patch?

Typically, there are manufacturing drawings created by an engineering group that are then reviewed and officially released for production. Wire is then ordered, sometimes delivered in a raw state, then cleaned, pickled, and drawn to a specific diameter. When completed, off to production:

  • Heading/Forming
  • Cleaned
  • Thread Rolling
  • Secondary (drilling/turning/milling/straightening), if applicable
  • Heat Treatment
  • Surface Treatment
  • Patch Application

So which process is most important?

They all are! If a non-conformity is not detected “in process”, the manufacturer will invest more time and resources in further processes, and hopefully detect the non-conformity during a final sample inspection, or even worse, at the customer.

Contact us through, and find out what robust quality processes we encourage Bossard manufacturers to practice to ensure good quality fasteners for our customers.


Tony Peters
Quality Manager

January 19, 2018
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Are Prints Needed for Fasteners?

What is a “special” fastener?  It is important to differentiate between standards and specials when identifying fasteners to be purchased or quoted.  If a fastener can be defined in a simple text description, it is not “special” and should not require a blueprint. See the following standard metric fastener description per ISO 8991:

Hexagon head bolt ISO 4014 – M12 x 80 – 8.8 – A2C

Customers will often create prints for fasteners and detail every dimension. This slows down the quoting process because every dimension has to be verified as “standard” or “special” by every manufacturer who looks at the print. Best practices for specials is to dimension only those items that are non-standard, and reference a dimensional standard for those items which are not special. For standard parts, a print is not needed, so save yourself the trouble and don’t make a print!

Contact us through with any questions or more information regarding standard and special fasteners and components.


Doug Jones
Applications Engineer




January 12, 2018
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Why You Should Be Prepared for Industry 4.0

You may be hearing about the fourth industrial revolution, otherwise known as Industry 4.0. What does this mean? Ever since technology became integrated into the workplace during the third industrial revolution, companies have become more efficient.

To keep up with the ever-changing industry, more and more companies are using digitalization to streamline their systems. Now that we are getting deeper into the technological age, the integration of advanced technology such as cloud computing, 3D printing, artificial intelligence, and so much more is being integrated into the workplace.

What does this mean for you and your company? This means utilizing advanced technology and implementing it into the workforce or workplace. Industry 4.0 and IoT will create transparency which creates maximized efficiency and reduced downtime.

Bossard has created Smart Factory Logistics which keeps you at the cutting edge of the industry. If you would like to learn more about Industry 4.0 and manufacturing, check out our other pages such as the 7 steps to get ready for Industry 4.0 and digitalization or how will Industry 4.0 impact your supply chain?.

January 05, 2018
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What is a Metal Locking Tie?

metal locking tie

A Metal Locking Tie (MLT) is a cable bundling product that is made of stainless steel. It has a self-locking head to increase efficiency in installations. The head locks into place at any place along the tie body to provide convenience and ease for your toughest jobs.

Uses & Performance

While on the job the smooth surface and rounded edges protect the worker and increase safety on the job site. This product can be used for outdoor, indoor, and underground applications, including direct burial. The Metal Locking Tie is a strong durable method of cable bundling. Metal Locking Ties can be used for both general-purposes and corrosive environments.

Self-Locking Head

This patent design has an aggressive locking head for a quicker locking, tighter installation. With a unique locking ramp this assures the self-locking head is locked in any positon. The strengthening ribs increases the locking hold for safety and security on the job site.


Check out more about Metal Locking Ties visit at For more information, or if you have any questions please reach out to us at

December 22, 2017
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The Nut vs. The Bolt: Which One Is Stronger?

Engineers design joints to withstand a certain amount of clamp load, but clamp load is not easy to measure when assembling a joint, so torque is specified. The assembler knows they have a “good” joint when the proper torque is achieved, indicated by an audible click of the wrench, or a green light.

Now consider what happens if too much torque is applied, and the joint starts to yield. If the bolt is the weaker joint member, it will begin to stretch, necking down in the threaded portion, eventually breaking before it ever reaches the prescribed torque. In this case, the assembler stops his work and raises a red flag – something is wrong and the problem is addressed.

In the second scenario, we again apply too much torque and the joint starts to fail, but the nut or tapped hole begins to yield instead of the bolt. As the internal threads start to fail, friction and heat are created, and galling or seizing of the threads may occur. In some instances, we may achieve the click or green light, indicating that we have a “good” joint and the assembler moves on to the next job, not realizing that yielding has occurred. Once the product is put to use, the service loads may be enough to cause a catastrophic failure of the already compromised joint.

So, which is stronger – the nut or the bolt? As a rule of thumb, always make sure that the nut (or nut member) is stronger than the bolt!

Check out our thread engagement length calculator on to make sure that your joints are designed properly.

Doug Jones
Applications Engineer



November 24, 2017
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