What Is Bolt and Its Types? | Parts of a Bolt | Types of Bolts | Types of Nuts | Types of Washers

What Is Bolt and Its Types?

A bolt is a mechanical fastener with threaded shafts. The bolts are closely related to screws, which are also mechanical fasteners with threaded shafts.

This type of fastener is usually inserted through two parts, which have aligned holes. By some definitions, whether a thing is a bolt or a screw depends on how it is used.

The bolt is inserted through the parts that all have unshielded holes, & a nut is then screwed onto the bolt to provide a clamping force & prevent axial motion.

A screw my first pass through the first part with an evacuation hole, but its threads are being fastened with threads in one part. Using two numbers separated by a point, the bolts are classified according to their strength.

This grade is often stamped on the heads. The points are not decimal but act as a denominator. The first number is the ultimate tensile strengths (UTS) in MPA divided by 100, & the second numbers are the ratio of yield strength to UTS.

Common classes are 5.8, 8.8, & 10.9. For example, grades 8.8 bolt has a UTS, at which it fails, is 800 MPa and will receive 80% (640 MPa) of this value.

A bolt is a type of fastener that is used to connect two parts together. The bolts join the part non-permanently, i.e., the parts can be separated from each other using a suitable tool. Nuts are also used on the bolt to make the fastening process more effective.

Also, Read: Parts and Functions of Grinding Machine | Grinding Machine | Grinding Machine Types

Parts of a Bolt:

#1. Head

The head is the topmost part of a bolt. It serves as a gripping surface for the instrument. To tighten or loosen the bolt, a tool with the appropriate bit must hold the head. Most bolts have a head wrench-type.

In other words, a wrenching bit should be placed around the head of the bolt. However, some bolts use screw-type heads where the bit is placed in the center of the head.

Whether wrench or screw-type, all bolt heads provide a gripping surface so that the bolt can be tightened or loosened with a tool.

#2. Shank

There is a conch under the head. The Shank is the smooths part of a bolt that is devoid of threading. It is designed to prevent radial movements of the included workpiece.

Without the leg, the bolt is more likely to be loose. Some workpieces produce vibrations, while others are exposed to vibrations in the environment around them.

When the included workpiece vibrates, the bolt may loosen if it does not feature a leg. Lack of leg means that the bolt will fully extend from top to bottom (with the exception of the head). Therefore, the vibration may push the bolt backward from the included workpiece.

#3. Threading

All bolts have threading. Threading is one that allows a bolt to move in or out of the workpiece. However, most bolts do not have complete threading.

They have ahead, followed by a smooth leg and finally threading. Depending on the type of bolts, the Shank may cover a larger surface area than threading. However, all bolts have threading.

The threading of a bolt works together with the internal threading of the workpiece to join them. The bolts have external threading that is located outside their bottommost part. This allows the external threading bolt to be moved in or out of the internal threading of the workpiece.

---

Useful Article for You

• What Is Spring in Mechanical?
• Types of Wrenches
• Types of Hammers

---

Types of Bolts:

The Bolts are one of the most versatile structural fasteners, available in a vast array of configurations to suit different materials & strength requirements.

These fasteners differ mainly in thread specification, length, and head size, with different combinations of these characteristics resulting in bolts with different functions.

They usually require a drilled hole and a filler nut or mating portions taped for installation, and, unlike screws, they are generally not tapped.

The terminology that distinguishes between bolt types is often for inconsistent and incorrectly used screws, so it is best to select your bolt based on your project specifications rather than the exact name indicated on the supplier’s website.

• Carriage Bolt:- Carriage bolts feature a domed or countersunk head with a square underside that prevents post-installation from operating. They are often used with wood & masonry.
• Flange Bolt:- The flange bolt is a special type of hex head bolt that has an integrated flange that acts as a washer component to distribute the load more evenly.
• Hull Bolts:- Similar to carriage bolts, some hull bolts have a square-shaped counters top. Others have a domed design. These bolts are ideal for heavy-duty applications such as industrial machinery.
• Hex Head Bolt / Hex Head Cap Screw:- Characterized by their hexagonal head shape, hex head bolts are a wide range of bolts requiring installation with a wrench. They are available in many lengths & threading varieties. The hex head cap screw has a tight tolerance and is the most common hex bolt range.
• Square Head Bolts:- Like hex head bolts, square head bolts are defined by their head shape — that is, square. This head design facilitates tooling gripping while allowing easy installation.
• Socket Head Cap Screw / Allen Bolt:- The socket head cap screw has a flat chamfered top surface with smooth or curly cylindrical sides. Forged heat-treated alloy examples are high-strength fasteners intended for the most demanding mechanical applications with special alloy aggregates.
• Additional bolt types:- Other bolt types that we can custom manufacture include anchors, belts (e.g., eye, hook, J, & U), countersunk, lag, & T-handle bolts.

Also, Read: What Is Dial Gauge? | Parts of Dial Gauge Indicator | The Internal Arrangement of Dial Gauge | Working of Internal Parts

Types of Nuts:

The Nuts are available in a variety of shapes, sizes, materials, & thread patterns. Although your nut selection is somewhat constrained by your choice of the bolt – especially in terms of size and threading – you should still choose the size and material of the nut head that best suits your application.

• Coupling Nut:- A coupling nut is a long, cylindrical nut that connects two male threads. These components can be used to add length to an installation.
• Flange Nuts:- Similarly to flange bolts, the flange nuts are around the flange that acts as an external washer and allows for greater load distribution.
• Hex Nuts:- Hex nuts are hexagon-shaped. This nut is extremely versatile but requires a wrench for installations. The types of hexes nut we supply include finished hex, semi-finished hex, hex flange, hex jam, hex, and slated hex.
• Locknuts:- Locknuts are available in a range of sizes and are used to secure other nuts and prevent them from loosening. Types of locknuts include all-metal locknuts with top or side locking features, serrated hex flange, and nylon inserts.
• Slated Nuts:- Slated nuts are designed and manufactured such that they can form a locking mechanism with a cotters pin or a safety wire.
• Square nuts:- Square nuts are characterized by their square shape. This head size increases the surface area of ​​the fastener and experiences a greater amount of friction, reducing the risk of loosening it.
• Wheel nuts:- Wheel nuts are a wide range of nuts used in automotive wheel applications.
• Additional nut types:- Other walnut types that we can custom manufacture include hats, castles, conicals, caps, thumbs, and feathers.

Also, Read: Parts of Benson Boiler | Working Principle of Benson Boiler | Construction of Benson Boiler

Types of Washers:

Washers are disc-shaped components that provide controlled control of overlocking and friction when used with other fasteners.

These fasteners may include dentures, indentations, and other unique structural mechanisms for use in more specific applications.

In general, they perform a variety of tasks, including loosening the fastener assembly, protecting the surface under a fastener, and evenly distributing pressure during installation and use.

Compared to nuts and bolts, washers are much less available. However, among the washer types, there are significant differences. Like the nuts, the washers should complement your selected bolt and suit your unique fastening application.

• Beveled washers:- Beveled washers are made with a slightly angled surface, allowing them to join materials that are not parallel to each other.
• Flat washers:- Flat washer is the most common type of washer. They provide larger surface areas for better load distribution. Different thicknesses are available for different types of hold strength.
• Lock washers:- Lock washers come in many sizes, such as choppers, toothed rings, conical, or springs, each designed to prevent slippages of fasteners in demanding applications. They are commonly used in an environment that experiences a high degree of vibration.
• Structural washers:- Structurals washers are one of the most heavy-duty washer options available. This thick fastener is designed to withstand the highs load pressures of construction.

Also, Read: What Is Hydraulic Braking System? | Construction of Hydraulic Braking System | Parts of Hydraulic Braking System

---

Frequently Asked Questions (FAQ)

Different Types of Bolts

Basic bolts consist of a head and cylindrical body that has part of its length (or shaft) threaded (if it’s completely threaded, it’s a screw). The bolt screws into a nut that has internal threads to match the bolts.

Types of Bolts

• Anchor Bolts
• Blind Bolts
• Carriage Bolts
• Double End Bolts
• Eye Bolts
• Flange Bolts
• Hex Bolts
• Machine Bolts and Machine Screws
• Penta-Head Bolts
• Round Head Bolts
• Shoulder Bolts
• Socket Head Bolts
• Square Head Bolts
• T-Head Bolts
• U-Bolts

Bolt Head Types

• Flats Bolt Head: A counter shank head with flats top.
• Oval Bolts Head: A counter shank head with a round head top.
• Pan Bolts Head: A slightly rounded head with a short vertical side.
• Truss Bolts Head: An extra-wide head with a rounded top.
• Round Bolt Head: A dome head.
• Hex Bolts Head: A hexagonal head.
• Hex Washer Bolts Head: A hexagonal head with a round washer at the bottom.
• Slotted Hex Washer Bolts Head: A hexagonal head with a built-in washer and slot.
• Socket Cap Bolts Head: A small cylindrical head using a socket driver.
• Button Bolts Head: A low-profile round head with a socket driver.

Types of Bolts and Their Uses in Construction

In construction, various types of bolts are used depending on the specific application and requirements. Here are some commonly used bolts and their uses:

1. Hex Bolts: Also known as hexagon head bolts or hex cap screws, these bolts have a hexagonal head and a threaded shaft. They are used in a wide range of construction applications, such as fastening steel structures, connecting wood components, or securing heavy machinery.
2. Carriage Bolts: Carriage bolts have a round head with a square-shaped collar beneath it. They are designed to be used with a corresponding square hole or slot to prevent the bolt from rotating while tightening the nut. Carriage bolts are often used in applications where a smooth, finished appearance is desired, such as attaching decorative elements or joining wood components.
3. Anchor Bolts: Anchor bolts are used to attach structural elements to concrete or masonry surfaces. They typically have a threaded end for securing a nut and washer, while the other end is embedded in the concrete. Anchor bolts are crucial for securing building columns, steel structures, equipment, and other heavy loads.
4. Eye Bolts: Eye bolts have a loop or eye-shaped end instead of a traditional head. They are primarily used for lifting heavy objects, securing cables, or creating attachment points for ropes, chains, or hooks. Eye bolts are commonly found in construction projects involving rigging, hoisting, or suspension systems.
5. Lag Bolts: Lag bolts, also known as lag screws, are heavy-duty screws with a hexagonal head. These bolts have coarse threads and are used for fastening wood to wood or wood to other materials, such as attaching beams, brackets, or large fixtures to wooden structures. Lag bolts require pre-drilled pilot holes to ensure proper installation.

Different Bolt Head Types and Their Advantages

Different bolt head types are designed to provide specific advantages and functionalities in construction and other industries. Here are some common bolt head types and their advantages:

1. Hex Head: Hex head bolts, also known as hexagon head bolts or hex cap screws, have a six-sided head. The advantages of hex head bolts include:
   • Easy to grip and tighten with a wrench or socket.
   • Provides a large surface area for applying torque, allowing for higher tightening forces.
   • Widely available and commonly used, making them easy to source.
2. Square Head: Square head bolts have a square-shaped head with four sides. The advantages of square head bolts include:
   • Provides a large contact area, reducing the risk of rounding off the head when tightening.
   • Offers increased resistance to loosening due to the flat sides of the head.
   • Ideal for applications where a high level of torque is required.
3. Round Head: Round head bolts have a domed or rounded head with a smooth surface. The advantages of round head bolts include:
   • Provides a finished and aesthetically pleasing appearance.
   • Reduces the risk of injury or snagging on the bolt head.
   • Suitable for applications where a smooth and flush finish is desired.
4. Pan Head: Pan head bolts have a low-profile, rounded head with a flat or slightly curved top surface. The advantages of pan head bolts include:
   • Provides a smooth and low-profile appearance.
   • Minimizes the risk of snagging or catching on the bolt head.
   • Suitable for applications where a flush or countersunk installation is required.
5. Countersunk Head: Countersunk head bolts have a conical head that sits flush with or below the surface of the material when installed. The advantages of countersunk head bolts include:
   • Creates a flush and smooth surface when installed, minimizing protrusions.
   • Reduces the risk of catching or snagging on the bolt head.
   • Commonly used in applications where a flat surface is desired or to prevent obstruction.

Bolt Material Options and Their Properties

Bolts are available in a variety of materials, each with its own properties and characteristics. The choice of bolt material depends on factors such as the application, environmental conditions, load requirements, and desired mechanical properties. Here are some common bolt material options and their properties:

1. Carbon Steel: Carbon steel is a popular choice for bolts due to its affordability, availability, and general strength. Different grades of carbon steel, such as Grade 2, Grade 5, and Grade 8, offer varying levels of strength and hardness. Carbon steel bolts are susceptible to corrosion and are typically coated or plated for improved corrosion resistance.
2. Alloy Steel: Alloy steel bolts are made from a variety of alloying elements, such as chromium, molybdenum, and vanadium, in addition to carbon. Alloy steel bolts offer higher tensile strength, hardness, and resistance to wear and fatigue compared to carbon steel. They are commonly used in applications that require greater strength or where specific mechanical properties are needed.
3. Stainless Steel: Stainless steel bolts are known for their excellent corrosion resistance, making them suitable for applications where exposure to moisture or corrosive environments is a concern. Stainless steel contains chromium, which forms a protective oxide layer that helps prevent rusting. Common stainless steel grades used for bolts include 304 and 316, with 316 offering higher corrosion resistance, especially in marine environments.
4. Titanium: Titanium bolts offer high strength-to-weight ratio, excellent corrosion resistance, and resistance to extreme temperatures. They are commonly used in aerospace, marine, and chemical industries. Titanium bolts are lightweight, non-magnetic, and biocompatible, making them suitable for applications where weight reduction, non-reactivity, and biocompatibility are crucial.
5. Brass: Brass bolts are primarily used in applications that require good electrical conductivity or resistance to corrosion. Brass is an alloy of copper and zinc, providing decent strength and resistance to atmospheric corrosion. They are often used in electrical and plumbing installations, as well as decorative applications.

Top-Rated Bolt Manufacturers in the USA

---