This article takes an in-depth look at types of bolts.
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Bolts are essential components engineered to fasten and secure different sections of assemblies. They come equipped with threads and are commonly paired with a complementary nut. Bolts facilitate the connection of aligned, unthreaded holes by passing through them and are secured with the nut.
The shaft of a bolt is a round component that handles the shear forces applied to it and prevents lateral movement of the connected components. The bolt shaft is divided into two main parts:
Assemblies may encounter or create vibrations, potentially causing bolts to loosen up. If a bolt lacks a shank and has a fully threaded shaft, vibrations might cause it to loosen from the assembly.
The bolt head is built to endure the axial forces that hold the secured materials together. A wrench or driver applies torque to the bolt head for tightening or loosening. Bolt heads come in various shapes and designs, including the following:
Typically, bolts are used alongside the following mechanical devices:
A nut serves as the female counterpart of a bolted joint with a threaded hole, providing the needed clamping force to bind multiple parts and curtail axial movement. The securement arises from the combined forces exerted: the nut applies axial force, causing compression of the fastened elements. This compression generates friction between the bolt and nut threads, preventing unintended loosening. Additional methods like lock washers, jam nuts, split pins, and thread-locking fluids may be utilized to ensure the joint remains secure against prolonged vibrations and impacts.
A washer is a thin, flat disc featuring a central hole, routinely placed under the bolt head and nut. Its primary role is to evenly distribute the load of the threaded fastener over a larger area, thus preventing deformation of the materials being fastened. Washers composed of softer materials such as plastic, rubber, or urethane can effectively absorb vibrations, diminishing the risk of bolt thread loosening. Additionally, specialized washers are capable of forming waterproof seals to stop liquids from infiltrating the bolt joint.
Understanding essential fastener terminologies related to bolts is crucial for engineers, manufacturers, and anyone involved in selecting or specifying mechanical fasteners for industrial and construction applications. Below are the most important bolt terminology definitions and explanations, along with guidance on how to interpret bolt specifications across both metric and imperial systems.
The shank diameter is the diameter of the smooth, unthreaded section of the bolt shaft. It is also commonly known as the nominal diameter or body diameter. This measurement is central to identifying the strength properties and fitment of bolts in precision engineering, automotive, and construction projects.
The major diameter is the largest diameter of the bolt thread, measured between two opposite crests or the topmost surfaces of the threads. It is often the same as the nominal diameter. A bolt’s major diameter plays a critical role in determining compatibility with corresponding nuts and tapped holes, ensuring optimal load distribution and fastener reliability.
The minor diameter, also known as the root diameter, is the smallest diameter of the bolt thread. It is measured between two opposite roots or the bottommost surfaces of the threads. This parameter influences a bolt's shear strength and is a key consideration in threaded fastener design and selection.
The pitch diameter is the diameter that lies midway between the major and minor diameters of the bolt thread. This measurement is essential for threading compatibility, thread engagement, and ensuring proper assemblies in manufacturing and repair operations.
The fundamental dimensions of a bolt thread include:
The nominal length of a bolt is the total axial length of the bolt shaft, which is the sum of the grip length and the thread length. The grip length refers to the length of the unthreaded portion, while the thread length is measured from the first complete thread adjacent to the shank to the end of the bolt shaft. Choosing the correct nominal length is critical for applications that demand precise clamping force and proper joint integrity.
The thread pitch is the axial distance between two adjacent crests of the thread. This measurement is used for metric fasteners and is typically expressed in millimeters. Thread pitch directly influences the mechanical properties of a bolt, such as tensile strength, grip, and suitability for high-vibration environments.
Metric fastening components are manufactured according to ISO and DIN standards. Understanding how to interpret metric bolt sizes is essential for selecting the right bolt for your specific hardware requirements, preventing misfits or weaknesses in mechanical assemblies.
If you come across a bolt with the sizing M10-1.0 x 20, it indicates that the bolt has a nominal diameter of 10 mm, a thread pitch of 1.0 mm, and a length of 20 mm.
You might also see a bolt specification such as M12-50. In this case, the thread pitch is not specified, indicating that the bolt has a coarse thread. Here, the nominal diameter is 12 mm, and the bolt length is 50 mm. Understanding the difference between coarse and fine threads is key for selecting fasteners with the correct load-carrying capacities and resistance to loosening during service.
Choosing between fine and coarse threads is an important consideration in industrial bolting, influencing a bolt's resistance to stripping, durability under dynamic loads, and overall ease of assembly. Fine threads are often used for precision alignment and high-strength assemblies, while coarse threads are more resistant to cross-threading and ideal for quick installation in softer materials.
How do you read imperial bolt sizing, given that TPI (threads per inch) specifies the number of threads per inch of the bolt thread and is used exclusively for imperial or US fasteners?
If you encounter a bolt with the sizing ¼�-20 x 2�, it means the bolt has a nominal diameter of ¼ inch, a thread pitch of 20 threads per inch, and a length of 2 inches.
Understanding threads per inch is critical when sourcing replacement hardware, ensuring compatibility with existing equipment, and adhering to North American fastener standards such as ANSI and ASME. The correct TPI is essential for preventing cross-threading, maximizing load-bearing capacity, and achieving secure installations, especially in automotive, aerospace, and heavy machinery sectors.
Right-handed threads tighten when rotated clockwise and are the most commonly used type across almost every fastener application. In contrast, left-handed threads tighten when turned counterclockwise. These are employed in situations where right-handed threads might loosen under pressure or rotational force. Examples of applications for left-handed threads include bicycle pedals, vehicle wheels, circular saw blades, and gas supply valves, where rotational forces could otherwise compromise fastening security.
Choosing the correct thread direction is essential for safety and reliability in critical connections. Many fastener catalogs and engineering specifications clearly indicate thread direction to help avoid selection errors in assembly lines and field repairs.
A chamfer is a beveled edge near the tip of the bolt, created by cutting away part of the first thread. This feature helps facilitate the insertion of a nut and allows the bolt to fit more easily into holes. The chamfer angle is measured from a line perpendicular to the bolt's axis. Chamfered bolt ends help prevent thread damage during assembly and ensure smoother engagement, which is especially important in automated manufacturing environments or when precise alignment is required.
To further enhance your understanding of bolt specifications and fastener selection, here are several other industry-relevant terms:
By mastering fastener terminologies and understanding bolt specifications, users can compare products, ensure engineering compatibility, and achieve optimal performance in every bolted connection. When sourcing bolts from leading manufacturers or suppliers, be sure to verify product certifications, adherence to ISO and ASTM standards, and availability of technical support to make informed procurement decisions.
Here are various types of bolts.
Anchor bolts are designed to join components into concrete surfaces. They are commonly used in the construction industry. They are usually found in the bases of steel poles. They are also used in attaching façade systems to reinforced concrete walls. There are two classifications of anchor bolts:
There are two common types of anchor bolts are:
Arbor bolts are pre-assembled bolts with a washer permanently attached to the head. The head features a sinker design with ridges around it. Arbor bolts typically have a dark or black finish and are distinguished by their reverse threads. The reverse thread is a key feature of arbor bolts and is essential to their function.
Unlike other types of bolts, arbor bolts are not typically available in home improvement or hardware stores. They serve a specific purpose and are not considered general fasteners. Arbor bolts are used in electric saws to secure the saw blade, playing a crucial role in the saw's operation and ensuring the blade remains properly attached and functional.
Blind bolts are a specialized type of bolt designed for use in situations where hex bolts and rivets are impractical due to restricted access. They offer good tensile strength and can support loads that are slightly less than those handled by standard bolts. Blind bolts are used to join objects through a pre-drilled hole in one of the components, making them ideal for applications with limited space because of adjacent components.
The head of a blind bolt features a series of teeth that interlock with a nut, providing additional strength and stability when secured. The term "blind bolt" refers to their use in applications where access is limited to only one side of the objects being joined, making it impossible to see the opposite side. Blind bolts consist of a pin, collar, and sleeve, with the collar designed to collapse as the bolt is tightened.
Carriage bolts are partially threaded along their shank and feature a round head with a square neck, which prevents the bolt from turning during fastening. Also known as plow or coach bolts, they are primarily used in wood applications. Carriage bolts offer tensile and shear strength that varies based on the material they are made from. For example, stainless steel carriage bolts have a shear strength of 90,000 psi.
A carriage bolt is secured using a nut with a washer that is attached to the threads on the flat end of the bolt. When determining the size of a carriage bolt, it is important to measure them from under the head to the end of the bolt. Measuring from under the square neck leads to inaccurate measurements. A pilot hole of the diameter of the flat end of a carriage bolt has to be drilled prior to inserting the bolt. It is important to use a washer with a nut when securing a carriage bolt to reduce potential surface damage.
Elevator bolts are named for their use in elevator construction. Their flat head is designed to secure components without obstructing the elevator's movement. The key feature of elevator bolts is their flat, round, thin head, which sits flush with the surface when the bolt is fastened.
Elevator bolts have threads that extend partway up the shaft. Beneath the flat head, there is a square neck similar to that of a carriage bolt, which ensures a secure connection and prevents the bolt from turning during installation. Elevator bolts are available in various materials, diameters, lengths, and sizes to suit different applications.
Elevator bolts are commonly used in the construction of conveyors, where their flat heads provide a smooth surface essential for proper operation. Their secure connection helps prevent conveyors from vibrating or shifting. Additionally, elevator bolts are well-suited for fastening soft materials like softwoods, fabrics, and plastics.
The distinguishing feature of eye bolts is their head, which is shaped like a metal ring or circle. Eye bolts can be found with or without a shoulder. Shoulder eye bolts are stronger and provide greater support compared to those without a shoulder. The threads on an eye bolt extend the full length of the bolt, from its flat end up to its ring-shaped head. For shoulder eye bolts, the threads stop below the shoulder.
The different types of eye bolts include:
Flange bolts feature a circular, washer-like flange beneath their head, which helps distribute the clamping force over a larger area. In vehicles, they secure the outer casing of engine and transmission systems, providing protection. In piping systems, flange bolts are used to firmly join the ends of two flanged pipes together.
A flange bolt features a washer integrated into and attached to its head as a single, solid unit, enhancing its strength and stability. The threads of flange bolts extend the full length of the bolt, from its flat end up to the washer. Available in a wide range of sizes, styles, and materials, flange bolts can also be custom-made for specific applications. Their design enables them to distribute the load evenly across the entire surface of the bolt head.
Flange bolts are commonly used for attaching exhaust systems in vehicles and securing pipes. They are typically made from carbon steel or stainless steel to ensure strength and durability.
Hanger bolts are headless bolts with different types of threads at each end. One end features lag screw threading, while the other end has machine screw threading with a blunt tip. These bolts are made from materials such as stainless steel, zinc-plated steel, galvanized steel, and brass. They come in diameters ranging from 0.375 inches to 0.5 inches (9.5 mm to 12.7 mm) and lengths from 0.5 inches to 6 inches (12.7 mm to 152.4 mm). Typically, the diameter of the lag screw portion is smaller than that of the machine screw portion.
The lag and machine threads on a hanger bolt are separated by a square shoulder, which serves as a head for both sets of threads. This shoulder prevents the bolt from being installed beyond the length of the threads. The dual-thread design allows hanger bolts to be used in both metal and wood applications. To install a hanger bolt, first drill a pilot hole, then lubricate the bolt with wax or oil. Finally, use a wrench or drill bit to tighten the bolt.
The six-sided hexagonal head of a hex bolt gives it a distinctive appearance. This type of bolt is unslotted and can have threads running the full length of the shank or only on part of it. Hex bolts are available in a wide range of materials, types, styles, sizes, and dimensions. They are renowned for their exceptional tensile strength and versatility, making them suitable for a broad array of applications.
Hex bolts are used with pre-tapped holes and a nut that is tightened using a wrench, socket, spanner, or hex key. The hex head makes them easy to grip from multiple angles, which makes their installation and removal easy. They are categorized by their size, material or finish, and full or partial threading. The three sizes of a hex bolt are its length, metric thread size, and its thread pitch or the number of threads per inch.
JJ-bolts have a curved end resembling the letter "J," with threads at the opposite end of the curve. The curved section provides two points of contact for securing materials. Their unique shape facilitates easy insertion into pre-drilled holes. To install J-bolts, place them into two pre-drilled holes: one hole accommodates the flat end of the "J," while the other holds the threaded portion. J-bolts are particularly suited for anchoring walls to the ground or connecting beams.
J-bolts are commonly used in construction to anchor walls and support beams. In gardens and parks, they secure benches and playground equipment to concrete surfaces. In industrial settings, J-bolts are employed to fasten machinery, such as presses and conveyor belts, to the facility floor.
A lag bolt, also known as a lag screw, features a hexagonal or square head and a threaded shank. Similar to hex bolts, the threading on a lag bolt may extend the full length of the shank or just a significant portion, depending on its design. The shank and threads are tapered to facilitate driving the bolt into wood. This threading creates friction between the connected materials, enhancing the strength of the connection and preventing slippage.
The larger size of lag bolts assists in forming stronger and more secure connections and provides excellent surface grip. The installation of lag bolts into wood is easy due to their tapered shank, which makes assembling of large pieces quicker. It is important to note that lag bolts are difficult to remove when installed, a factor that necessitates careful planning when they are being used.
Machine bolts may have either a hexagonal or square head and come with standard right-hand threads. Machine bolts shorter than six inches are fully threaded, while those longer than six inches are threaded up to twice the diameter of the bolt plus an additional half inch. These bolts are unslotted and are installed using a nut and socket wrench. They are made from materials such as carbon steel, stainless steel, and bronze, with bronze and stainless steel options offering corrosion resistance.
Machine bolts are available in several grades, with grades two, five, and eight being the most commonly used in the United States. Higher grades of machine bolts offer greater tensile strength and hardness, making them suitable for applications requiring strong, secure connections. Proper installation of machine bolts requires tightening them to the correct torque, as insufficient tightening can lead to joint failure.
Pentagon® tamper-proof bolts, also known as penta bolts, are industrial fasteners made from stainless steel. They feature a five-sided head shaped like a pentagon and are available in various sizes. The pentagon design helps prevent the accumulation of debris or dirt, which can be easily cleared away. When used to secure ground surfaces, penta bolts are recessed to minimize tripping hazards.
Penta bolts are commonly used in city, municipal, and government infrastructure applications, including manhole covers, waterworks, valve boxes, meter boxes, ground vaults, electrical junction boxes, and concrete enclosures. They are classified as security bolts because they require a specially designed tool for loosening or removal, making them ideal for applications where tamper-resistance is essential.
Penta head bolts are available in several styles, including machine bolts, washer head bolts, washer head captive style bolts, and lag bolts, and come in various sizes to accommodate different applications.
Plow bolts feature a flat, domed, or convex head with a tapered neck, and can have either fully or partially threaded shanks. The neck of a plow bolt is square and tapers as it connects to the shank and threads, matching the diameter of the bolt. The head is designed with an 80° taper. Plow bolts have standard right-hand threads, with short bolts having full-length threading and long bolts having minimal threading. The head diameters of plow bolts range from 0.375 inches to 1 inch (9.5 mm to 25.4 mm).
Originally, plow bolts were designed to secure a plow share to the frog of the plow, allowing soil to pass smoothly over the bolt's head. Today, plow bolts are commonly used to fasten components of heavy equipment because they sit flush with the surface, providing a clean finish. They are available in various grades, with grades 5 and 8 being the most common.
Rock bolts are threaded steel bars inserted into drilled holes in rock faces to stabilize the rock and ensure the safety of workers. Once installed, fully grouted rock bolts are secured with resin or cement, filling the entire hole. In contrast, partially grouted rock bolts are placed into the drilled hole but secured with a smaller amount of grout, which allows for a faster installation process.
Rock bolts consist of a threaded end and a free end. The free end is inserted into the drilled hole, while the threaded end is anchored to the wall, ceiling, or equipment such as scaffolding. A face plate is attached to the threaded end with a nut, helping to distribute the load evenly.
Rock bolts are used to stabilize rock faces by transferring loads from the exterior to the interior of the rock mass, effectively binding the rock together to prevent shifting or loosening. Self-drilling rock bolts streamline this process by integrating drilling, grouting, and anchoring into a single operation, and come with a pre-attached face plate. Other types of rock bolts include MDX bolts and fiber-reinforced polymer rock bolts, each offering distinct benefits for various applications.
Sex bolts are fasteners consisting of a barrel-shaped female component with internal threads that encase a threaded male component. The female part functions as a nut and is typically about the same length as the male part. Both components feature a flange that provides a stable bearing surface and ensures a more even connection. These bolts are particularly useful for fastening materials that are sensitive to abrasive components. They are commonly used in applications such as paper binding, helmets, railing systems, furniture, playground equipment, signage, bathroom partitions, and various other products.
Shoulder bolts feature a distinctive design with a shank that has a larger diameter than the threaded portion but is smaller than the bolt head. The heads of shoulder bolts can be either hexagonal or round. The shank is designed with a cylindrical section that provides stability and ensures the threads remain secure when inserted into a hole. Shoulder bolts are particularly suited for applications subjected to vibrations or heavy loads, offering reliable performance under such conditions.
Since shoulder bolts have a low profile, they can be used in tight spaces where traditional bolts do not fit. When a shoulder bolt is fully installed, the cylindrical portion extends beyond the threads to act as a shaft or dowel for rotating bearings, guides, axles, and pivot points or mounting pins. They are used in plastic injection molds to accurately align the mold halves.
SSocket head bolts have a cylindrical shape with a barrel head featuring a hexagonal socket designed for tightening with an Allen wrench. The head of socket head bolts is smaller compared to traditional bolts, allowing them to be recessed when installed. Like shoulder bolts, socket head bolts are well-suited for applications with limited space. In some cases, they are recessed into a countersunk hole so that the top of the bolt is flush with the surface of the item being fastened.
Socket head bolts are favored for their high tensile, yield, and shear strengths, which make them suitable for demanding applications. Their small head size allows them to be used in compact countersunk holes. Variations of socket head bolts include button heads, which are domed and smooth, flange heads that feature a load-distributing flange, low-profile heads designed for tight spaces, self-locking heads that prevent loosening under vibration, and vented heads that have a hole drilled through the bolt’s length to facilitate the venting of fluids and gases.
Square head bolts are named for their distinctive head shape, which can be either four-sided or six-sided. Often, these bolts are countersunk to ensure that their heads do not protrude. The shanks of square head bolts can vary based on their intended application, and the threads begin at the end of the shank, extending toward the head. The length of the threads can differ depending on the specific design of the bolt.
The square heads of square head bolts offer a larger surface area, allowing for greater torque to be applied without the risk of stripping or breaking the bolt. This feature makes them particularly useful in applications that require significant force for securing equipment and heavy machinery. Additionally, their shape and pointed tips facilitate easy insertion into pre-drilled holes, enhancing their effectiveness in various fastening tasks.
Structural bolts are employed with hex nuts to join structural steel members and are manufactured to comply with ASTM standards A563 and A194. They are classified based on their size range, proof load, and minimum yield and tensile strength. These bolts are considered high-strength due to their superior tensile strength and capability to create secure, tight connections. Additionally, structural bolts can endure higher torque, which is crucial for maintaining stability in steel constructions.
SAE Grade 9 structural bolts, also known as grade 9 hex cap screws, represent the highest strength category of structural bolts, with a tensile strength of 180,000 PSI. These bolts are designed for extremely demanding applications that require heavy-duty performance, such as in manufacturing machinery and bulldozers. Additionally, Grade 9 structural bolts are coated with yellow zinc chromate to enhance their corrosion resistance, making them suitable for challenging environments.
Stud bolts are characterized by their fully or partially threaded cylindrical design without a head. They are secured using nuts on both ends of the stud, ensuring a tight connection. Partially threaded stud bolts feature an unthreaded section in the middle, with threaded portions of varying lengths at each end. For certain applications, stud bolts can be paired with washers and additional nuts. They are commonly used in high-pressure piping systems, wheel hub assemblies, and pipeline flange connections.
The ends of stud bolts are rounded, sheared, saw cut, flat, or chamfered. Their length is measured from one end of the threads to the other end of the threads and come in quarter inch incremental lengths. They are normally used for joining components with internal holes such as wheel hub assemblies.
The types of stud bolts include:
There are two types of partially threaded stud bolts:
T-head bolts feature a threaded shank with threads of varying lengths and a head shaped like a "T" or rectangle. This design resembles a hammer, which has led to them being called hammerhead bolts. The unique T-shaped head allows these bolts to be used in slots, where they are secured by a 90-degree turn of the head, ensuring a stable and secure fit.
T-head bolts come in various configurations, including those with a square neck, a long extended T, a flat head T, and a domed T. These bolts are commonly used to secure channeling, guide rails, and flush fittings. The T-shaped head is designed to fit seamlessly into the corresponding T-shaped slots of drill swivel heads, facilitating a secure and stable connection.
Tap bolts are fully threaded bolts featuring a hexagonal head and standard right-hand threads. The end of the bolt is chamfered or rounded to protect the first threads and ease their entry into parts. Available in various lengths, tap bolts are versatile and suitable for a wide range of applications. For proper installation, the bolt must extend sufficiently into the pre-drilled hole to allow for the placement of a nut and washer on its shank.
Tap bolts come in different threading configurations depending on the manufacturer, but the standard thread length is typically twice the diameter of the shank. They are usually installed with a washer and a hex nut. Made from stainless or hardened steel, stainless steel tap bolts are preferred for use in corrosive environments. Common applications for tap bolts include adjusting pulley tension and securing motors.
Toggle bolts, also known as butterfly anchors, are designed to support heavy loads such as brackets and shelves. They consist of two main components: a fully threaded bolt and a metal wing toggle. To install toggle bolts, first, a pilot hole is drilled into the surface, typically drywall, where the item will be mounted. The wings are then removed, and the item to be secured is positioned on the bolt. After the item is correctly placed, the wings are reattached to the bolt, expanding behind the surface to provide a secure hold.
Once the item to be hung is attached, the bolt and toggle are inserted through the pre-drilled hole. The bolt is then pulled back to allow the wings to spread behind the surface. Once the wings are fully open and positioned, the bolt is tightened to firmly secure the item in place.
There are two basic types of toggle bolts: standard and spring. The key difference between them lies in the design of their wings. Standard toggle bolts feature metal wings that fold against the threads and shaft of the bolt during insertion into the pre-drilled hole. In contrast, spring toggle bolts use an anchor with wing-like extensions that resemble a nut. During installation, the anchor is first placed into the pre-drilled hole, and as the bolt is screwed into the anchor, the wings expand on the interior of the wall, providing a secure hold.
Tork bolts, also known as shear bolts or breakaway bolts, are distinctive security fasteners with a unique design. They feature either flat or countersunk heads, as well as button heads. The structure of a Tork bolt includes one head placed on top of another, connected by a breakaway connector. The upper head is hexagonal, allowing for easy installation with traditional wrenches. This design is intended to enhance security by ensuring that the bolt can be securely fastened but will break away if tampered with or subjected to excessive force.
A Tork bolt is designed so that the hexagonal head shears off or breaks away once the maximum torque is reached. This feature ensures that the bolt is permanently secured in place and makes it challenging to remove with conventional tools. When the head is detached by a wrench, the remaining portion of the bolt cannot be gripped, providing an exceptionally secure fastening solution.
Since Torx bolts don’t require a specialized tool for installation, they offer an effective solution for securing products, equipment, or components that might be susceptible to tampering with other types of bolts. Their design helps safeguard items against unauthorized relocation, tampering, or interference.
Track bolts typically feature a round or circular head, often with an oval shape that has a round face and two holes—one at the top and one at the bottom. These holes are designed for attaching the bolt to tracks or equipment. Track bolts come with either round or square necks, and their design can vary depending on the specific application and requirements of the bolt.
Track bolts are primarily used to fasten tracks, railway signals, footbridges, and trackside equipment. Designed to withstand the demanding conditions of high-speed rail traffic, these bolts are built for exceptional durability due to the extreme wear and stress they encounter. Typically made from high-strength steel, track bolts have strength grades ranging from 8.8 to 10.9, with grade 10.9 being the most common. They are substantial in size, often weighing over two pounds (0.907 kg) and measuring nearly six inches (15 cm) in length.
U-bolts are shaped like a "U" with threaded ends on each arm. They are crafted from various metals depending on the strength needed for their application, with steel, stainless steel, copper, and brass being the most commonly used materials. The size of U-bolts is defined by the distance between the arms and the overall length from end to end.
A common use for U-bolts is supporting piping to rest, guide, or hold pipes. The sizes and thicknesses of U-bolts is designed to fit the various sizes of pipes. Non-gripped U-bolts are the most common form and do not restrict axial movement of piping. Gripped U-bolts serve as anchors and restrict pipe movement. When gripped U-bolts are installed, there is no space between the pipe and the curve of the U-bolt.
Expansion bolts consist of a bolt, a nut, and an expansion sleeve that covers the bolt's shaft. They are particularly useful in situations where access to the backside of the surface to be secured is limited. The head of the expansion bolt rests on top of the expansion sleeve and is inserted into a pre-drilled hole in the material. As the nut is tightened, the sleeve expands outward against the walls of the hole, creating a firm and secure grip. This expansion provides a tight hold that resists loosening from vibrations or shock loads.
Expansion bolts are well-suited for securing connections in porous materials like brick, stone, and concrete due to their design. They are intended for single-use applications and are not meant to be removed once installed. The key component of an expansion bolt is its sleeve, which must be durable and capable of making contact with multiple anchor points to ensure a stable and secure hold.
Industrial bolts are robust fasteners designed to endure extreme weather conditions and chemical exposure. This category encompasses a variety of bolt types, including hex bolts, leg bolts, eye bolts, U-bolts, and stud bolts. The term "industrial bolt" broadly refers to bolts used for connecting equipment, parts, and components in demanding environments. Typically, these bolts are installed permanently, necessitating exceptional strength and durability to ensure reliable performance.
Industrial bolts are classified broadly due to their diverse applications and the varying types needed for different industrial uses. While standard industrial bolts have been in use for centuries, ongoing innovations are continually improving designs to meet the evolving demands of industrial processes. Despite these advancements, the fundamental components of industrial bolts typically include a shaft, head, threading, and sometimes a rod. Although nuts are commonly used with industrial bolts to secure them, they are not always necessary for every application.
As anticipated, the variety of industrial bolts are produced from several different metals, chosen based on the specific application requirements. The most commonly used metals for manufacturing industrial bolts include steel, stainless steel, titanium, bronze, brass, and aluminum. Among these, carbon steel and hardened steel are the most prevalent due to their strength and durability.
Steel grades for industrial bolts include Grades 2, 5, 8, and various alloyed steels. For stainless steel bolts, common grades are 18-8, 316, and 410. The durability of these bolts is often enhanced through coatings such as zinc, hot-dip galvanizing, and chrome, with galvanizing being the most commonly used to provide additional corrosion resistance.
Unlike other types of bolts, industrial bolts must be carefully selected to ensure optimal performance, durability, stability, and endurance. They play a critical role in securing equipment, platforms, floors, machinery, and other vital components of industrial operations. Their proper selection is essential for maintaining the integrity and safety of these systems.
Metric bolts are produced using dimensions based on the metric system, which includes measurements for thread pitch, shaft lengths, and diameters. The metric system is favored by manufacturers because it simplifies scaling dimensions up or down. Metric bolts larger than 6 mm are typically stamped with "ISO M" to indicate compliance with ISO standards.
A metric bolt is defined by its length being measured in millimeters, with bolts shorter than 6 mm typically being categorized under the imperial measurement system. For a bolt to be classified as metric, both its shaft and diameter are measured in millimeters, with the diameter determined by measuring across the bolt's flat surface. Metric bolts come in five thread types and ten strength grades, and are available in nineteen standard sizes and ten non-standard sizes..
TThe primary distinction between standard and metric bolts lies in their thread specifications. Metric threads are characterized by their pitch, which is the distance between the peaks of adjacent threads, measured in millimeters. In contrast, standard threads are identified by the number of threads per inch. Additionally, metric bolts are specified by their major diameter in millimeters, which is the measurement across the bolt from the peak of one thread to the peak of the thread directly opposite.
Nearly every type of bolt can be manufactured from stainless steel, which comes in around 150 different grades and surface finishes. The most commonly used grades are Grade 304, known for its general commercial applications, and Grade 316, which is specifically designed for marine environments. Additionally, Grades 18-8 and A2 are often used interchangeably with Grade 304, as they share similar properties, leading some users to consider them equivalent.
Stainless steel is used in bolt manufacturing due to its outstanding resistance to corrosion and varying resistance to acids. Stainless steel alloys are iron-based and contain at least 10% chromium, along with varying amounts of other metals. These additional elements influence the steel’s resistance to acids, chemicals, and heat, as well as its strength. The chromium in stainless steel forms a protective, sealed layer on the surface, which is the primary reason for its corrosion resistance.
Stainless steel is easy to fabricate and is commonly used in the production of consumer products, including those for food preparation. Its attractive appearance enhances the aesthetic appeal of products. Additionally, stainless steel's hygienic properties make it ideal for use in food preparation equipment, medical instruments, surgical tools, and hospital equipment.
A thru-bolt consists of several components: a nut, a washer, a shank with an expansion taper, and an expansion clip. At the opposite end of the expansion taper and clip, there is a plain, blunt nip located above the nut and washer. Some specialized thru-bolts feature depth indicators on their threads. These bolts are friction anchor bolts designed to exert substantial stress on the substrate, making them particularly suitable for use with concrete substrates.
TThru-bolts are installed by first drilling a hole with a diameter matching that of the bolt. After thoroughly cleaning the hole, the expansion taper end of the bolt is inserted into the hole until it reaches just before the threaded portion. The bolt and washer are then tightened, causing the tapered end to push into the expansion clip. This action forces the clip to expand and press against the walls of the hole. The torque applied during the tightening of the nut sets the anchor and generates a clamping force, securing the bolt in place.
Proper installation of thru-bolts includes the correct spacing between bolts and avoidance of placing them too close to the edge of the substrate. Thru-bolts, also known as through bolts, use the same principle as expansion bolts to secure items to brick, concrete, and cement. The key to the performance of thru-bolts is to ensure that they are installed with the correct torque.
American Fastener Technologies manufactures a diverse range of fasteners for construction, marine, and oil and gas applications. The company produces fasteners in both metric and standard English measurements. Their reputation for precision and exacting tolerances drives the demand for their products. In addition to their extensive selection of standard fasteners, American Fastener Technologies' skilled engineers can also design and produce specialty fasteners for unique applications.
US Bolt Manufacturing produces bolts for a range of applications including offshore drilling, production equipment, power generation, pumps, valves, Navy ships, and pressure vessels. The company's primary focus is on safety-related applications and includes the manufacture of hex head bolts, flange bolts, hex nuts, lock nuts, and specialty fasteners. US Bolt Manufacturing is certified to ISO 9001:2015 and ISO 17025:2017 standards. Their success is attributed to their rigorous quality control, which involves closely monitoring the production process from raw materials through to the final products.
American Bolt Corporation manufactures a range of products including sockets, bolts, screws, nuts, and washers, featuring nine different styles of bolts. They are equipped to produce both single and double-ended studs, as well as anchor bolt assemblies with tack welds and plate washers. Additionally, American Bolt offers services such as cutting, threading, crimping, and provides packaging and kitting solutions.
Conformance Fasteners, based in Michigan, manufactures a diverse range of bolts, screws, nuts, and other fasteners. The company holds an ISO 9001:2008 certification and has a strong collaboration with the automotive industry. They produce bolts and screws in various lengths and designs, including flanged bolts, elevator bolts, and carrier bolts. A key advantage of working with Conformance Fasteners is their commitment to reducing customer costs and offering engineering assistance.
All State Fastener Corporation manufactures bolts, screws, nuts, washers, and various specialty products from materials such as aluminum, brass, bronze, steel, and stainless steel. They boast one of the largest selections of cold-formed and hot-forged bolts and screws. All State Fastener offers fasteners designed for weight reduction, heat and corrosion resistance, and strict tolerance requirements. The company takes pride in providing both standard fasteners and those for critical safety applications.
The types of bolts are:
Die stamping is a cold forming process that takes a sheet of metal, referred to as a blank or tool steel, and cuts and shapes it using a single or series of dies to create a desired shape or profile. The force that is applied to the blank modifies and changes its geometry...
An eyelet is a metal, rubber, or plastic ring with flanges are used to strengthen or reinforce holes punched in thin fabrics. It is a smaller counterpart of a grommet that is bigger in size and used for more heavy duty materials...
A fastener is a non-permanent or permanent mechanical tool that rigidly connects or affixes two surfaces or objects together. Non-permanent fasteners can easily be removed without damaging the joined materials...
A metal bracket is a fastener or connector designed to secure and hold two pieces or objects together. They are used to support shelves, stabilize equipment, fasten uprights, or serve as decorative accents. Metal brackets come with...
Shim Definition: The material used to cover empty spaces is referred to as a shim. For instance, window and door jamb construction frequently involve the usage of construction shims. A shim can be made from materials on hand, especially when...
Metal stamping is a coldworking process that transforms sheets of metal into specific, preset shapes. It uses specialized tooling which involves the stroke of the punch that brings conformational change to the metal sheet...
A metal washer is a small flat piece of metal that has a hole in the center and is used as a spacer, a method for absorbing shock, or distributing the load of a fastener. The hole in the middle of a metal washer allows for a bolt or screw to pass through...
The metal stamping process began during the industrial revolution as a cold forming means for producing frames and handlebars for bicycles. From its beginnings in Germany, it has grown into an essential part of modern industry for the production of parts and components for a wide variety of industries...
A self-drilling screw is a type of tool that has the same design features as a drill bit or cutting tool. As the name implies, self-drilling screws do not require a pilot hole in order to perform as a fastener...
Bolts are mechanical devices used in assembling and fastening objects, typically used with a matching nut. They are designed to be installed in aligned unthreaded holes of multiple parts...
Ball screws are mechanical linear actuators that consist of a screw shaft and a nut that contain a ball that rolls between their matching helical grooves. The primary function of ball screws is to convert rotational motion to linear motion. Ball nuts are used in...
Cold forming can be defined as the process of continuously forming a specific shape or design from a metal wire without adding heat. This is aided by hammers, dies, and punches at a very high speed...
Powder metallurgy is a manufacturing process that produces precision and highly accurate parts by pressing powdered metals and alloys into a rigid die under extreme pressure. With the development and implementation of technological advances...
A lead screw is a kind of mechanical linear actuator that converts rotational motion into linear motion. Its operation relies on the sliding of the screw shaft and the nut threads with no ball bearings between them. The screw shaft and the nut are directly moving against each other on...
Thread rolling is a type of threading process which involves deforming a metal stock by rolling it through dies. This process forms external threads along the surface of the metal stock...