What Are the Types of Fasteners Used in Automotive?

What keeps all the different car parts together? A car has thousands of small pieces that need to connect to each other like puzzle pieces. The things that hold it all together are called fasteners. They come in many shapes and sizes to suit different automotive needs.

There are various types of automotive fasteners. Bolts and screws securely attach metal parts through threading. Nuts tightly clamp pieces by threading onto bolts. Rivets are small aluminum cylinders that get smashed on both ends to grip panels together. Clips work like small clamps to neatly hold on trim pieces.

Keep reading to learn more about automotive fastener types and the special jobs they do in your vehicle. You’ll see why cars need the right fastener for every spot, from securing your engine to mounting wheels. 

Fasteners in Auto Manufacturing 

Fasteners play a vital role in automotive manufacturing. Without the countless screws, bolts, nuts, and other fasteners holding a vehicle together, there would be no cars. An automotive fastener must clamp parts securely, while resisting heavy loads and vibrations from driving.

Metal is the primary material for these fasteners due to its strength and durability. Steel and aluminum alloys are commonly used, thanks to their ability to withstand pressure without breaking. 

To protect against rust and corrosion, metal fasteners often receive protective coatings, like galvanization or anodization. These finishes help fasteners maintain their holding power for the lifetime of the vehicle.

While not as robust as metals, plastic fasteners also serve an important purpose in cars. Made through injection molding of materials like vinyl, these fasteners:

  • Are significantly cheaper than their metal counterparts
  • Don’t rust, conduct heat, or electricity
  • Are used for non-structural connections and spacers

Their lower cost helps offset overall production expenses. They also perform well in non-load bearing applications.

Advanced machining techniques, such as CNC turning, shape many automotive fasteners with precision. CNC lathes remove material in a controlled spinning process to cut consistent threads. This allows customization, like captive fasteners, with intricate geometries that fit perfectly while withstanding heavy use.

Types of Automotive Fasteners and Their Applications

There are many kinds of screws, bolts, and clips used on cars. Each one has a special job to do. Some fasteners hold parts together tightly, others let things move around a bit. 

We’ll look at common types of automotive fasteners and how they help cars work.

1. Nuts

A nut is a small metal part that has a spiral cut threading inside, so it can fit over a bolt. The threads on the nut lock it into place when you tighten it against another part. It works with bolts and washers to attach many different automotive parts. 

Some different types of nuts are:

  • Hex nuts: It’s the most common type used on cars. It has six sides like a hexagon shape, which makes it easier to turn with a wrench. 
  • Cap nuts: They have treading on one end because the other side has a flat domed head. 
  • Barrel nuts: The cylindrical nuts slide into holes perpendicular to the bolt axis.
  • Flange nuts: Having a hexagonal head, these nuts are wider at the bottom. So, there’s no need to use a washer under them.

Nuts help hold all kinds of things like wheels, doors, hoods, and exterior trim. They attach heavy car parts securely, so nothing falls off when you’re driving. Mechanics also use nuts as spacers or for adjusting parts sometimes. Different sizes let them control how tight things fit together. 

2. Bolts

Bolts are externally threaded metal rods that are used along with nuts to securely attach different vehicle components together. They come in many lengths and sizes to suit various automotive applications. 

The design of a bolt features a head at one end for turning with a wrench or socket, and a threaded shaft for screwing into a matching nut. The unthreaded part between the head and thread is called shank. The shank experiences less wear and abrasion than the threaded portions. It also provides more precision during installation since the bolt can extend farther through parts without rubbing on the threads. 

In vehicles, bolts are commonly found fastening things like:

  • Engine components 
  • Suspension arms, control arms, and other chassis parts
  • Transmission 
  • Dashboards

Bolts serve as sturdy but adjustable fasteners that hold vehicles together through years of operation and repair. Their simple threaded design allows easy assembly and disassembly as needed.

3. Screws

Screws are one of the most common types of automotive fasteners. They work like bolts but without the need for a nut. Instead, the threads along the shaft grip tight into matching holes. These fasteners are made with CNC machining because they require a high-level of precision.

Some different types of screws are:

  • Hex screw. It has a hex-shaped top that lets you twist it with a wrench. They can be fully or partially threaded and are suitable for pre-tapped holes. 
  • Countersunk head screw. It’s similar to a hex screw, except its head sits totally flat with the surface.
  • Pan head screw. It has a rounded top and is good for keeping water and dirt out of connections. 
  • Self-tapping screw: It can actually cut its own threads as they go into a surface. This makes them great for attaching sheets of metal or plastic.

4. Lock Washers

Lock washers help nuts and bolts stay tight. When you put one under a nut or bolt head, it adds friction. The bumps on the washer push back when something tries to turn the fastener. This helps nuts and bolts from becoming loose over time. 

Cars have lots of vibrating parts that can slowly loosen bolts. Lock washers fight against this and keep everything well-connected.

5. Clips

Clips are small fasteners that hold many auto parts in place. Made of both plastic and metal, they work kind of like wall anchors, which means you squeeze them through a hole and they expand out on the other side. This keeps trim pieces and panels securely mounted. 

In cars, clips are used to attach interior panels, door panels, and plastic bumpers. Whether plastic or metal, they fit through holes and latch on tightly. They do a good job keeping things from moving around. But you need special tools to remove them without damaging anything.

6. Studs

Studs are special types of automotive fasteners. They are a kind of screw but don’t have a head like regular screws. Instead, they are welded or pressed right into metal parts, which help them to stay in place. 

The most important thing studs do is hold wheels on vehicles. Each wheel has several studs sticking out to attach it to the car. Nuts thread onto the end of the studs to tightly clamp the wheel in place. Other things studs might hold include engine components, suspension parts, and trim pieces inside and out. 

7. Clamps

You will find all kinds of clamps holding hoses and tubes in place under a car’s hood. Things like coolant hoses, brake lines, and vacuum tubes need to stay exactly where they are to help engines and systems work properly. 

Made of mostly metal and sometimes plastic, clamps squeeze tightly around components when screwed up. The right clamp makes sure everything stays put no matter how much the vehicle moves. 

8. Pins

Pin fasteners keep car parts together but still allow some movement. Both metal and plastic pins are used for fastening various types of car components.

Cotter pins hold the wheel axles in place but let them move a little side to side. The movement is important for turning the wheels smoothly. 

Clevis pins connect parts of the brakes, so the brakes can still operate while moving up and down a bit over bumps. Lynch pins, on the other hand, hold axles to different rigs on off-road vehicles. This lets the axles pivot to handle rough trails without leaving the rig. 

9. Springs 

Springs are usually made of metal, such as steel. They can be compressed or stretched from their normal shape, which helps some parts like wheels stay attached to axles or suspension parts connected to the vehicle frame. 

These types of automotive fasteners bend and flex during driving to give your car a smooth ride. Their elastic properties mean parts can move around a little without coming loose. Different types of springs have different shapes too, like clips that go around a shaft end. No matter the type, all automotive springs let vehicles roll along while safely fastening various parts. 

10. Rivets

Rivets are tube-shaped and fit through pre-drilled holes. You have to use a special tool to expand them inside the hole. 

Made of both metal and plastic, there are different types of rivets used in the automotive sector. They are good for attaching metal parts, making them perfect for putting a car’s shell, hood, and doors in place.

11. Specialty Automotive Fasteners

Specialty automotive fasteners feature unique designs just for automotive uses. Some of them include push-in fasteners, rivet nuts, panel clips, captive nuts, etc. 

The materials and shapes of these fasteners allow them to join some parts that regular bolts and nuts can’t. Panels and trim often have spots too small or hard to reach for hands. Captive nuts, for example, which don’t fall out easily are the right choice for joining these parts. 

Carmakers test these special fasteners a lot to make sure they last in places that get very hot or wet. Without the right fasteners, parts might not stay on right or come loose over time. 

Conclusion

From the engine to the wheels, fasteners are the tiny parts that keep your car in one piece. They come in all shapes and sizes, each with a specific job to do. Whether it’s a bolt holding on an engine part or a clip keeping the trim in place, fasteners are what make your car a functioning machine.

Need precision automotive or aerospace fasteners manufactured? Contact Zintilon to discuss designing and CNC machining parts to your specifications, tolerances and deadlines. We’ll get you the fasteners you need on time and on budget.

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