Fasteners are an essential component in manufacturing and construction, they provide a strong, secure connection between two or more components, they are versatile, easy to use, cost-effective, and ensure safety.
They come in various forms like screws, bolts, nuts, washers, rivets and nails and can be used in a wide range of industries, from construction to aerospace.
What Is a Fastener?
A fastener is a mechanical hardware that is used to join two or more objects (usually non-permanent connection) together and can be dismantled easily if required.
These hardware’s can take many forms, including screws, nails, bolts, nuts, rivets, and pins. They are used to connect and maintain the relative position between multiple parts.
Fasteners are made from a variety of materials, including metal (carbon steel, stainless steel, aluminum, brass, copper alloys, etc.) and plastic, and are used in a wide range of applications, from construction and manufacturing to household and automotive repairs.
They are designed to provide a strong, secure connection between the objects they are joining and typically need specialized tools for their installation and removal.
Classification of Fasteners
Fasteners can be classified into different categories based on various factors, including their design, material, and intended application. Some common classifications of fasteners include:
- Threaded fasteners: This type of fastener includes screws, bolts, and nuts. They are designed with threads that allow them to be screwed into a material, and they can be used to clamp two or more parts together. Examples include machine screws, wood screws, nuts & bolts and lag bolts.
- Pins and Rivets: These types of fasteners are used to hold two or more parts together and are typically installed through one side of the parts being joined, and then retained by deforming the pin or head of the fastener. Examples include cotter pins, dowel pins, and pop rivets.
- Clinch fasteners: These types of fasteners are designed to be driven into a material, creating a cold work hardening of the material and then the clinched part holds the fastener in place. Examples include self-clinching nuts, studs and standoffs.
- Snap fits fasteners: These types of fasteners are used to hold two or more parts together by means of a spring-loaded mechanism. Examples include snaps, zippers and velcro.
How to select correct Fastener?
Selecting the correct fastener for a given application is crucial for the proper functioning and safety of the structure or device. Here are some key factors to consider when selecting a fastener:
- Materials: The fastener should be made from a material that is compatible with the materials of the parts being joined and can withstand the loads and stresses that the joint will experience.
- Strength: The fastener must be able to withstand the loads and stresses that the joint will experience. The strength of the fastener is determined by its size, material, and design.
- Environmental factors: The fastener should be able to withstand the environmental factors that the joint will be exposed to, such as heat, cold, humidity, and corrosion.
- Standards and Regulations: The fastener should meet the applicable international standards and regulations, such as ISO, DIN, ANSI, and ASTM.
- Compatibility: The fastener should be compatible with the tools, equipment and method of installation, if it requires special tools for installation or special techniques for removal.
- Maintenance and repair: The fastener should be able to be removed and replaced if maintenance or repair is needed.
- Cost and availability: The fastener should be cost-effective and readily available.
Most Common Types of Fasteners
Some of the most common types of fasteners include:
- Screws: a type of fastener with a helical ridge, known as a thread, that forms a screw-like shape. They can be driven into wood or other materials by turning them with a screwdriver or drill.
- Nails: a long, thin piece of metal with a pointed tip and a flared end that is used to join materials by driving it into them.
- Bolts: A type of fastener that is characterized by a cylindrical shaft with a smooth exterior and a screw thread on one end. They are typically used in combination with a nut to hold materials together.
- Rivets: a cylindrical mechanical fastener that is used to join two or more pieces of material together. They are typically made of aluminum or steel and are inserted into drilled holes in the materials to be joined.
- Washers: a small, flat ring of metal or other material that is placed between a nut or bolt head and a surface to distribute the load and reduce wear on the surface.
- Clips and Clamps: A device that is used to hold two or more objects together, such as pipe clamps, hose clamps, and spring clamps.
- Nut: Nut is a nut is a type of fastener that is used in combination with a bolt, screw, or stud to secure two or more pieces of material together. It is typically a hexagonal or cylindrical shaped piece of metal or other material that has internal threads that match the threads of the fastener.
Bolts and their main Types
Bolts are a fundamental component of many construction, engineering, and manufacturing projects. They are used to fasten and secure materials together and come in a variety of types and sizes to meet specific needs.
Read more: 25 Main Types of Bolt Heads
In this post, we will take a look at some of the most common types of bolts and their main uses.
Types of bolts
- Hex head bolts: These are the most common type of bolt and can be found in many applications. They have a hexagonal head that can be tightened with a wrench or socket. They are available in a wide range of sizes and can be made from various materials, including steel, aluminum, and brass.
- Carriage bolts: These bolts have a round head with a square shoulder under the head. They are often used to attach wood to wood or wood to metal. The square shoulder prevents the bolt from turning while the nut is tightened, ensuring a secure hold.
- Lag bolts: Also known as lag screws, these are heavy-duty wood screws that are driven into wood using a wrench or socket. They are typically used for heavy load-bearing applications such as attaching wood beams to wood posts.
- Button head bolts: A type of bolt that has a low profile, rounded head that sits flush against the surface of the material it is being used on.
- Socket head cap bolts: These bolts are also known as Allen bolts and have a hexagonal recess in the head, typically tightened using an Allen wrench or hex key.
- U-bolts: These are U-shaped bolts with two threads and commonly used to attach pipes to various surfaces.
Read more: What is Anchor Bolt and their types?
Screw Fasteners and their Types
Screw fasteners are a versatile and common type of fastener that are used in many different applications.
They are designed with a helical ridge, known as a thread, that forms a screw-like shape. They can be driven into wood or other materials by turning them with a screwdriver or drill.
Types of Screws
Read more: Complete List of Screw Types.
- Sheet metal screws: These screws have sharp threads and a pointy tip, they are typically used in metal and plastic and are great for attaching thin sheets of metal to wood or other materials.
- Machine screws: These screws have a small, cylindrical head and a slotted drive, they can be used in a wide range of applications and are great for small mechanical devices.
- Wood screws: These screws have a tapered, pointed tip and a wide, flat head, they are designed for use in wood and other soft materials and are great for attaching wood to wood or other materials.
- Self-tapping screws: These screws have threads that cut into the material they are being driven into, creating a secure hold. They are great for attaching metal to metal or other hard materials.
- Drywall screws: These screws have a sharp, pointed tip and coarse threads, they are typically used in drywall and other soft materials, and are great for attaching drywall to wood or metal studs.
- Thumb screws: These screws have large knurled heads that can be turned by hand, great for easy installation and removal.
- Deck screws: These screws have large, flat heads and are coated for corrosion resistance, designed for outdoor use and most commonly used for deck building and other outdoor projects.
- Set screws: They have no head, have a cone point or cup point and used to secure an object within or against another object.
Read more: Self-Tapping vs. Self-Drilling Screws.
These are just some examples of the many types of screws available, each with their own specific characteristics and uses. The selection of the appropriate type of screw depends on the application, load and design requirements.
The use of the right type of screw for the job can help ensure a strong and secure hold, and can help to prevent damage to the materials being joined.
Rivet and their main types
A rivet is a mechanical fastener that is used to join two or more pieces of material together. They are typically made of aluminum or steel and are inserted into drilled holes in the materials to be joined.
The end of the rivet that is inserted into the hole is called the tail, and the end that protrudes out of the hole is called the head.
Rivets can be used in a wide variety of applications and are known for their strength and durability.
There are several types of rivets, each with its own specific features and uses.
Types of Rivets
- Solid Rivets: Solid Rivets are the most common type of rivets and are used in a wide variety of applications. They are made of a single piece of metal and have a cylindrical shape with a head on one end and a tail on the other. They are typically inserted into a pre-drilled hole in the materials being joined, and the tail is then mushroomed over to create a secure hold.
- Semi-Tubular Rivets: These rivets have a hollow center, reducing their weight and material cost. They are inserted into a pre-drilled hole and then the end is mushroomed to secure the hold.
- Blind Rivets: Blind rivets are fasteners that are used to join two pieces of material together without the need for access to the back side of the material. They consist of a mandrel that is inserted into a pre-drilled hole and then pulled through the material, causing the end of the mandrel to expand and secure the hold.
- Pop Rivets: These rivets work similar to blind rivets, they have a mandrel inside a hollow dome, when the mandrel is pulled, the dome expands and the mandrel breaks off to secure the hold.
- Split Rivets: These rivets have a split down the shank which allows them to be inserted into a pre-drilled hole and then opened up to create a secure hold.
- Countersunk Rivets: These rivets have a countersunk head and can be used to provide a flush finish on one side of the materials being joined.
- Shoulder Rivets: These rivets have a shoulder between the head and shank which allows the head to sit flush with the surface of the material.
Washer and their types
A washer is a small, flat ring of metal or other material that is placed between a nut or bolt head and a surface to distribute the load and reduce wear on the surface.
They are typically used to increase the surface area of the fastener, preventing damage and increasing the stability of the joint.
Washers also help to prevent leaks by creating a tighter seal and also can help to reduce vibration, noise, and other mechanical issues.
The main types of washers based on their configuration are listed below:
Types of Washers
- Flat washers: The most basic and common type of washer, flat washers have a flat surface on one side and a smaller diameter hole in the center. They are used to provide a smooth and even surface for a nut or bolt head.
- Lock washers: Lock washers are designed to prevent nuts and bolts from vibrating loose. They have a split in the center or a protrusion on the inner diameter that digs into the surface of the material, creating a secure grip.
- Spring washers: Spring washers are designed to provide a pre-load to a fastener, creating a tighter and more secure hold. They are typically made from a flexible material and are cone-shaped or bowed to create the spring effect.
- Fender washers: These washers have a larger outer diameter and a smaller inner diameter, providing a wider surface area to distribute the load. They are commonly used in automotive and marine applications.
- Beveled washers: Beveled washers have one angled surface, and they can be used to align parts at an angle, providing a smooth and even surface for a nut or bolt head.
- Shakeproof washers: These washers are specifically designed to prevent nuts and bolts from vibrating loose, by providing a spring action that grips onto the threads of the fastener.
- Wave washers: These washers are designed to provide a spring action, they are made of a single spring-like wave of metal, they are typically used in low-load applications.