Bolts are a type of mechanical fastener with external threads designed to be used in conjunction with a nut to join parts together by applying tightening torque. Bolts are typically inserted through pre-drilled holes in the material being fastened.
Unlike screws, which also feature external threads, bolts require a nut to function properly, as the nut threads onto the bolt to secure the joint. Bolts may be used in conjunction with a drilled hole into which they can be inserted.
It’s worth noting that the terms “bolting” or “types of bolting” are not commonly used in reference to bolts as fasteners. These terms are often associated with fabric bolting and bolting machines used in the fabric industry.
Different Types of Bolts
There are many different types of bolts, each having different characteristics that make them suitable for use across a wide range of applications. The principal types of bolts commonly used include:
#1. Arbor Bolts.
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.
#2. Anchor Bolts.
Anchor bolts are specially manufactured to attach the structural or non-structural elements to the concrete. Besides, they can use them to attach the steel to concrete, also. You can find several kinds of anchor bolts in the market.
The anchor bolt comes with the rooted end that has a consistent hexagonal bolt, flange, washer, and 90-degree bend. Also, there is the post-installed anchor. The anchor bolts have the threaded part on one end. Then, it also has the non-threaded part with an L shape on the other end. It can transfer several types of loads as well.
#3. Carriage Bolts.
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 it 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.
#4. Hanger bolts.
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.
#5. Elevator Bolts.
The elevator bolts are the threaded fasteners, which consist of the threaded shank. As they were used for the elevator systems, they are especially known as elevator bolts.
It is designed to hold the canvas belts for the elevator system or any mechanical systems as well. Well, the elevator bolt comes with a thin head and a square neck.
It helps to make the best surface so that it can retain the bolt from going through the soft material.
#6. Hex Bolts.
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.
#7. Lag Bolts.
The lag bolts are basically types of screw, which come with a woodscrew thread and a wrench head. It is used to attach the larger pieces of lumber together in wood materials.
Well, lag bolts are essential for home projects and renovation projects as well. All types of heavy-duty works such as the foundation or repairing roofs, must need heavy bolts so that they can grip the weight efficiently.
#8. J Bolts.
J-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.
#9. Shoulder Bolts.
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 the 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.
#10. U-bolts.
U-bolts are types of bolts that comes with a shape of the letter U. It used to support the pipework.
And, they are specifically measured by using pipe-work engineering. The U bolt is basically a curved bolt, which features the threads on each end. The curved design helps the bolt to fit around the pipes perfectly.
#11. Bent Bolts.
A bent bolt is a type of ITA fastener that works for fabrication, waterworks, metal building, and many other projects. It manufactures stainless steel that makes it more durable and rust-resistant. The bolts are perfect to use in generators, motors, pipes, or ignition engine mechanisms.
Moreover, it can meet the hardest tolerances very proficiently, which makes your product more durable and stronger.
#12. Track Bolts.
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.
#13. Round Bolts.
The Round bolts are specially designed according to the ASTM standards. The bolts are the most common type of bolt that comes with a smooth, round head. It gives the surface a finished and smooth look.
The bolt is quite the same as the carriage bolt. But they don’t have the square neck just like the carriage bolt. Likewise, they are best suited to secure the links in industrial applications.
#14. Square Bolts.
Just like the round bolts, the square bolts are also the most commonly used bolts for several projects. It comes with a threaded body and a square head. The bolt is ideal for the aesthetic purpose that gives it a rustic look.
It needs to be used with the flat washer to get rid of any damage. It can be found in numerous sizes that can range between the diameters of ½ inches and 1½ inches.
#15. Expansion Bolts.
Expansion bolts are ideal for securing heavy objects such as stone, brick, or concrete to the floors and walls. The bolt was specifically made with the lead.
Moreover, the heavy-duty bolt can handle both horizontal and vertical loads. Basically, it is designed to expand after it is installed. It needs a socket wrench or spanner to tighten or loosen the object. The yellow coating makes it corrosion-resistant.
#16. Eye Bolts.
Eye bolts feature a fully closed or partially closed-looped end in place of the traditional bolt head. The loop can be used in some cases for lifting the object to which the eye bolt is attached. Some eye bolts are not designated for lifting but rather can be used to route wire, cables, or other similar elements cleanly to avoid accidental interference.
Eye bolts can offer additional capabilities depending on the material composition and finish; some are suitable for low-temperature operations, while others are designed not to reflect light and therefore will blend into the background.
Eye bolts are available with or without a shoulder at the base of the loop. Other options include whether the loop is open or closed (including welded), whether the thread is internal or external, and whether it is designed with a pointed end, such as a wood screw, or intended for use with a nut to secure it.
Both metric and inch sizes and a variety of lengths are available. Different sizes of eye diameter enable these fasteners to be used for a variety of purposes.
#17. Stove Bolts.
The stove bolts come with a round flat head and a square nut design. The head of the stove bolt is designed to be used with the standard screwdriver. It is mainly used to join the pieces of metal parts together. The bolts are available in plenty of materials.
It is designed with steel, which is appropriate for everyday use. It can be fastened with a hex or square nut.
#18. Hook Bolts.
The hook bolt is a kind of curved steel fastener, which comes threaded on one end and hooked on the other end. The bolt looks like a question mark. The hook bolts are a type of anchor bolt that is used to fasten the shaft hangers.
It works for the extensions of beams and joists. Basically, they are perfect for hanging objects from the walls and ceilings.
#19. Nylon Bolts.
Nylon bolts are widely used and perfect for electronics. It provides high tensile strength. Also provides higher wear resistance than aluminium. They are not interactive with some chemicals and hydrocarbons. It weighs almost half of the aluminium.
Nylon bolts don’t burn; they melt. They are ideal for fire-resistant products. A high-quality nylon 6/6 has a tensile strength of 10000 psi. It’s not that weak but also not that strong as metals or aluminium bolts.
#20. Bronze bolts.
Bronze bolts are manufactured with an alloy mostly copper and tin, which contains a small amount of silicon. Usually, these types of bolts are used in marine environments. Bronze bolts have superior corrosion resistance. Ideal to use where longer support is required.
They are a little bit more costly than other metals, but they provide reliability and durability as expected. In additional benefit, they are highly thermal conductive, nonmagnetic, and superior in friction-reducing.
#21. Stainless Steel Bolts.
A stainless-steel alloy-made bolts are corrosion-resistant, durable, and stronger. They are ideal for use in outdoor environmental construction works.
Stainless steel shall not lose its properties. It has an incredible 100000 to 150000 psi tensile strength, which makes it ultra-durable, whatever the situation is. Ultimately, stainless steel is a wise choice if you want a safer solution and you have no objection to spending a little more money.
#22. Steel bolts.
Steel bolts are common fasteners. They are available plain and also with zinc or chrome plating or galvanization. Steel bolts have a variety of four grades: Grade 2, Grade 5, Grade 8, and Alloy Steel. They are made by mixing iron with carbon.
These steel bolts are relatively inexpensive. They are not ideal for use in hydraulic applications and wet environments. Also, they are more prone to corrosion and rust.
#23. Countersunk Bolts.
Countersunk bolts are one type of precision screws that have a countersunk head. They are intended to be used in pre-drilled holes. They can sit completely flush on the surface. The head has an angle of approximately 80 degrees.
Usually, there are driving slots in the head, and exception, some bolts don’t have slots. These bolts are likely the same as other types of bolts, but the only difference is that the head part is leveled with the surface area to enhance applicability.
#24. Flanged Bolts.
Flanged bolt comes in different head and body shapes, such as partial thread, full thread, full thread serrated, oversized full thread serrated, etc. They are manufactured with stainless steel and have a good mirror finish, which gives excellent corrosion resistance.
They have a wide variety of applications, like mechanics, plumbing, electronics, hard-to-reach applications, and large-scale applications. The head portion distributes the force across a greater surface.
#25. Plow Bolts.
It is a type of fastener that is used for making a mechanical connection where a smooth surface is required. Plow bolts are used in heavy construction types of equipment.
The head part is large and has a cylindrical shaft. They come in a variety of standards and sizes, and depending on the application, the right Plow bolt is selected. They are made with carbon steel, stainless steel, and metal alloys to have high wear resistance.
As you can see above, we have talked about 25 types of bolts and their uses. Hopefully, our writing piece will help you to know about them more precisely. So now, you can choose the right one depending on your project without any doubt. We wish that it would meet all your expectations properly.