Types of Fasteners and Their Application

Fasteners can be classified mainly into two categories: Permanent fasteners and Non-Permanent fasteners. As their names imply, a permanent fastener forms a permanent joint and the latter, a temporary joint. This versatility of having different types of bolt heads makes them high in demand. Mechanical fasteners are commercially available in many sizes and forms. They have different types which have several categories within themselves as well. Some of the most common types of fasteners are summarized below:

·       Screws: An externally threaded fastener with high durability and better grip strength

·       Bolts: A partially threaded fastener that holds two parts together also called threaded bolts

·       Nuts: It is internally threaded and fits into a bolt for securing objects and preventing loosening

·       Rivets: It forms permanent joints between objects, also contains pop rivets

·       Washers: A flat disc that is used with a nut and bolt for load distribution

·       Nails: A long and thin piece of metal used for joining objects

·       Anchors: it is used for fixing objects to concrete surfaces

All these types of fasteners mentioned above have further categories and relevant unique applications. Let’s dig into the details of the types of fasteners and also see what fasteners are used for.

Screws:

Screw fasteners are the most commonly used type of fasteners. They are highly versatile and durable. These socket screws have to fix eroded internal threads spanning across their whole length and their heads come in various shapes. Screws require internal threads in objects for holding them together. They make male threads into the object in which they are inserted. This reduces the need for pre-tapping.

There are many designs of screw fasteners commercially available for example machine screws, deck screws, sheet metal screws, lock nuts, lock washers, slotted headless set screws and many more. Some of these include:

·       Machine screws

Machine screws are used for fastening two metallic objects. They are inserted into already threaded holes that is why machine screws sometimes are also referred to as threaded fasteners.

·       Deck screws

This type of screw fastener- sometimes referred to as wood screws, has coarse threads and a tapered head. They are used in outdoor decks and wooden materials to resist corrosion.

·       Sheet metal screw

These crews have sharp-cutting threads for joining metal with other objects.  They can cut through sheet metals, plastics, and wood using their notched point. Sheet metal screws usually make the best bond in a nut threaded hole or tapped hole.

·       Drywall screw

They have coarse threads and tapered heads with fine tips to be inserted into drywall without damaging the material.

·       Hex Lag screw

These are large wood screws that are driven with a wrench instead of a screwdriver. They are used in heavy-duty applications. Hex cap screws have a hexagonal head shape, this hexagonal gripping point helps them build a greater torque. That is why these hex head bolts are known to be the strongest metal fasteners. Hex cap screw is sometimes also referred to as a wood screw.

These are some types of most common screws, now let’s jump towards the bolts, bolt head, and their types.

Bolts:

Another common type of fastener is bolts. These two pieces work together for holding unthreaded parts together. The bolt is a fastener with a straight, threaded shank and a head paired with a nut to clamp objects together. Some of the various types of bolts and nuts include:

·       Carriage bolts

Carriage bolts have square necks, convex heads, and multiple threads on them which are used for fastening wooden materials.

·       Allen bolts

These bolts have a hexagonal socket in their head for use with an Allen wrench

·       Plow bolts

These plow bolts are the flat square head bolts, countersunk, square neck, and unified thread, plow bolts are heavy-duty fasteners.

·       Flange bolts

They have a circular flange, a U bolts shape, under their head that acts as a washer for load distribution. These can be categorized as U bolts.

·       Fastening anchor bolts

These anchor bolts connect non-structured and structured elements strongly with each other.

·       Double End bolts

As clear from the name, double end bolts have sharp threads on both sides, hence these are used for the joining of two flanges together.

Bolts are considered as important as screws, and we have briefly defined some of their major types to elaborate their functioning.

Nuts:

An important fastener that works in pair with a bolt is a nut. It is internally threaded to fit with a bolt of the same size to improve the grip and provide increased torque. Lock Nuts are threaded in a way to an already defined nut or tapped hole. The different types of hex nuts include the following:

·       Wheel nuts

Also known as lug nuts, they are used for securing the wheels of vehicles.

·       Cap nuts

Socket cap nut protect internally threaded anchors of the fastener by avoiding their protrusion

·       Flange nuts

Used widely in assembly lines, these nuts have a wide flange at one end. This distributes the pressure and secures the part.

·       Coupling nuts

A coupling nut is an elongated jam nut for joining threaded rods. They also allow extending a rod.

Nails:

Nails are the most ancient fasteners used in history, and we still find a lot of applications that make use of nails. A nail physically appears a lot like a screw, but the difference can be easily spotted in them. One of the major differences between nails and self-tapping screws is that a nail doesn’t have machine threads on it, while a screw carries threading. No doubt a screw provides a better and strong joint, but a nail has a better shearing property, which makes it a good choice to be used in some applications.

Here we have discussed some major types of nails:

·       Common nails

This category of nails has a thicker body shank, and this thick property helps it to make a stronger joint between two or more objects. One of the major disadvantages of a common nail is that its thicker shank is visible in the joint and this greatly reduces the aesthetic property of the joint parts.

·       Box nails

Box nails have both a diamond point tip and head shapes tip. These are most commonly deployed in the joining of steel constructions.

·       Finishing nails

Finishing nails are flat square head set screws, which when used in the applications, make them blended in the application material with a better locking mechanism. This category of smooth rounded head nails leads to a neat finish and is utilized commonly in intricate and detailed design works.

·       Flooring nails

As narrated in the name, this category of nails is used in flooring applications.

·       Roofing nails

Roofing nails are said to be corrosion-free nails, and these have a wide head appearance.

·       Framing nails

These nails have many different manufacturing designs, often deployed in the installation of flush and associated applications. They also exhibit easy camouflage and concealment.  

So, these are some important types of fasteners that have been briefly narrated above. You must be wondering that of what material these nuts, screws, bolts, and structural washers are made of. Let’s move towards the materials required for making fasteners and plain washers.