Types of fasteners and how industries use them

Fasteners are used to connect two or more objects, either permanently or temporarily. There are many different types of fasteners, each with its own purpose.

Fasteners can be broadly classified as permanent or non-permanent. Permanent fasteners, such as rivets and nails, are single-use fasteners designed to connect two materials or parts permanently. Removing the fastener destroys it.

On the other hand, non-permanent fasteners are designed to allow easy removal and reuse. Fasteners such as bolts and screws are commonly used in many businesses and products because they allow parts to be disassembled and reassembled when necessary.

 

Threaded Fasteners

Threaded fasteners are most commonly used to assemble components, as they can be easily installed and uninstalled as needed. There are 3 main types of industrial fasteners: screws, bolts, and studs.

The bolt has a head on one end (this is usually a hex head) and is threaded on the other. They are typically used in conjunction with a nut (and sometimes a washer) to hold them in place.

Screws are like bolts in that they have a head at one end and a thread at the other. The main difference is that screws are typically used to screw into internally threaded holes. There are many different types of screws, such as cap screws, machine screws, and wood screws.

Studs are threaded at both ends and therefore have no head. They are used to connect two components with internally threaded holes.

 

Types of Threaded Fasteners

Bolts and setscrews – Bolts and set screws typically have a hexagonal head with a single thread. They can be used with a nut or in a threaded hole. The bolt usually has a shank under the head, while the set screw is threaded.

Carriage Bolts – Also known as cup square hex bolts, these have smooth circular heads with a square underside. These are used to secure wood to metal.

Eye Bolts – These bolts have a circular ring instead of the traditional head and are used to attach a rope or chain to a surface.

U-bolts – These bolts are used to attach round objects such as pipes and tubes to a wall or other surface.

Wood Screws – Featuring a smooth shank and tapered point, these screws are used in wood and come in various head shapes such as Phillips, slotted or posidrive.

Machine Screws – Machine screws are used with a nut or a tapped hole. Thread-cutting machine screws are also available, which have a thread-cutting point.

Self-Tapping Screws – Often referred to as self-tappers, these screws are used in sheet metals. Self-tapping screws tap their own thread.

Socket Screws – These screws have a smooth shank and an Allen head and are fastened using an Allen key. Socket screws come with various head shapes, such as buttons, socket caps, and countersunk.

Grub Screw – A grub screw is a special type of screw that usually does not have a head. These are used to prevent motion or rotation between two parts.

 

Nuts

Nuts are used with bolts to join two or more parts together. The most common type of nut is the hexagonal nut, but there are many different types of nuts for use in different applications.

Hex Nut – A plain, hexagonal nut with an internal thread. These are by far the most common type of nut and are used in many industries and applications.

Lock Nuts – These nuts are used when the nut needs to be locked in place without being clamped to any other object.

Nylon Insert Nuts – Commonly known as Nyloc Nuts, these hexagonal-shaped nuts have a nylon insert that prevents the nut from loosening due to vibration.

Shear Nuts – These cone-shaped nuts have a hexagonal gripping point that closes when maximum torque is reached, leaving only the cone-shaped nut that is difficult to remove.

Wing Nuts – Commonly used in applications where the nut needs to be removed frequently, wing nuts have two outer “wings” that allow for manual turning.

 

Washers

Washers are typically used between the head of a bolt, screw, or nut and the material to which they are clamped. Their primary function is to increase the bearing area of ​​the head, as well as to protect the material below it from damage. There are many different types of washers, each with its own uses.

Flat washers are the most common type of washer and are used to evenly distribute a load of a bolt, screw, or nut as the fastener is tightened.

Spring washers – These locking washers are designed to prevent the bolt, screw, or nut from loosening from vibration.

Cup washers – Cup washers form a cup to fit into the head of the fastener, creating a flush finish with the fastener head. They are used in conjunction with a wood screw.