In the automotive industry, normally, engineers are familiar with every aspect of the specifications and torque required in automotive manufacturing. The crucial information regarding tightening, however, is unfortunately rather scarce. This is a vital aspect of automobile fastening that requires further illumination. The fundamentals of bolts and adequate tightening procedures need a comprehensive study.

What does the automotive industry use?

Automotive fasteners are mainly nuts, bolts, and washers. Nuts secure bolts and screws to a surface, and they use interior female threading. Bolts are normally threaded with pins and rods; they always contain heads and are utilised for wheel construction. Washers used in automobiles tend to be small, flat discs with holes at their centre. They are used to hold several automotive bolts in order to prevent leakage, distribute pressure, and secure radiators.

Plastic fasteners, often crafted with vinyl, are manufactured through the process of injection molding, while metal fasteners are normally cold-worked and heat-treated to optimise strength, tightness, and durability. Stainless steel is highly valued as material for automotive fasteners because of its strength and resistance to corrosion.

Vehicle parts often corrode as a result of changing weather conditions; corrosion resistance is an important factor to consider when selecting the material for fasteners. One of the most reliable fastener materials for vehicles is titanium; however, its use is usually restricted to aerospace fastener applications.

The most critical issue that needs to be addressed

The most common type of fastener used in the automobile industry, without a doubt, is the Hex head bolt, closely followed by the hex-headed cap screw and the stud. A stud is a hybrid between a screw and a bolt. If any of the fasteners happen to become loose, the owner is likely to experience problems with his vehicle. For instance, a loose bolt in the engine or in the transmission area can prevent the car from starting, just as unsteady fasteners in the suspension or brake system can lead to extremely dangerous situations like accidents and collisions.

The risks are eliminated with the right tightening

Engineers need to ensure that the tension holding together the head bolts utilized in the critical areas is higher than the fasteners’ maximum load. The joints need to stay as tight as possible. Automotive fasteners are designed to withstand a load somewhere between 65% and 90% of their yield strength. Insufficient tension in the joint will cause force and vibration to loosen the bolt. On the other hand, excessive tension could damage the fastener.

‘Tightening’ is not the same as ‘torque’

When we say “tightening” with regard to fastener applications, we are referring to the pressure exerted on the parts clamped by the bolt. The fastener stretches, as the extension provides the necessary tension to keep the automobile’s parts together. Torque, on the other hand, refers to the rotational force applied; the screw rotates, creating the desired tension to hold the assembly. Automotive engineers can achieve the ideal tension on small fasteners through torque wrenches, and tightening for larger threaded bolts.

What affects the tension resulting from torque?

To achieve the right amount of tension resulting from tightness, technicians should consider a number of factors. First and foremost, when the torque reflects the fastener’s resistance to rotation; a bit of lubrication modifies the bolt’s ability to provide the necessary tension. It enables a bolt to exceed its original yield point.

Another important element that can alter the fastener’s ability to provide the desired tension is the installation of a hardened washer. It can serve as a bearing and hence, the fastener can rotate easier, as well as wear out faster. The lack of utilizing a washer to strengthen the tightness can make the bolt come loose faster in certain cases.

The bolts and nuts employed in the car manufacturing industry need to have the same grad; if you have a 10.9 grade bolt, it would require tightening with a 10-grade nut as well. To account for the washer, fastener grading, and lubrication, technicians normally use OEM standards as a guide.

Selecting the Right Fasteners for Specific Components

In order to select the right fasteners for automotive applications, it is imperative to become familiar with various aspects of manufacturing; adequate tightening procedures need to be comprehensively studied. Let’s explore the use of fasteners in specific components and aspects of vehicles:


Good lighting requires unique engineered fastening solutions such as thread-forming fasteners, gear head fasteners, attachment studs, and ball studs. The design and development of adjusting systems such as compact, mini and motorized gear box adjusters involve complex processes, with a carefully selected list of fastener tools to ensure their smooth functioning.


Engineered thread-forming fasteners and components are the foundation for strong fastening in the interior of vehicles, used right from instrument panels to centre consoles and door modules. Fastening in the case of interiors requires a careful application of tools handled by experts who have worked extensively on automotive applications. Application testing, samples, boss design, drive types, and clamp load-- these are important aspects of fasteners that need to be studied in order to select the right fasteners to enable a high level of performance.


Fasteners used include shoulder bolts, bolt- and crush-washer assemblies, couplers, lead screw brackets, spline gear shafts, seat actuation spindles and more. You require a certain standard of expertise when it comes to handling clinch fasteners and installation tooling and equipment. Unique engineered fasteners can be found in seat rails, seat tracks, and in the side panels.


A range of braking components is used in foundation and brake actuation applications. Foundation brakes use caliper bolts and caliper pins (utilized in disc brake calipers). Drum brakes and parking brakes use adjuster components and assemblies. For brake actuation, supply input rods, push rods, tie rods and damper assemblies are employed.


Thread forming screws are used for aluminum, magnesium, as well as tilt bolts and tilt pins used in both manual and power tilt and telescope steering columns. Experts should choose the right variety of components for steering columns, gears, and pumps.

Safety Measures

Critical components need to be selected by experts to use in air-bag and seat belt applications. This includes components and assemblies utlilised to retain air-bag modules in the steering wheel during deployment, as well as engineered fasteners that retain the air-bag and inflator.

ITA Fasteners brings you a wide range of fasteners that are of the highest quality. With our expertise as thought-leaders in the world of fasteners, we assess and understand your specific needs in the automotive industry, providing the most suitable fasteners to ensure that all parts of the vehicles are properly fastened, safe and secure!

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