The Essential Guide to Threaded Fasteners: Screws, Nuts and Bolts

Guide to Threaded Fasteners: Screws, Nuts and Bolts

Table of Contents:

Fasteners are hardware devices that join or secure two or more objects together. They come in various types and are important for various industries, from manufacturing and construction to transportation and automotive, where secure and reliable connections are imperative.

If you’re looking to purchase threaded products, you want to ensure the fasteners you choose are cost-effective and suitable for your specific project. We put together this essential guide to threaded fasteners that includes information on screws, nuts and bolts to help you better understand each part and make the most informed decision for your needs.

Threaded vs. Non-Threaded Fasteners

Fasteners have a simple function — to fasten things together and hold them in place. You have a choice between threaded and non-threaded fasteners. Each category comes with its own set of advantages.

What Are Threaded Fasteners?

Threaded fasteners are fixtures with spiral ridges that allow them to be twisted into materials to create secure connections. The twisting threads help to grip and hold these materials together. They’re a popular choice as they provide a strong and secure force yet are easy to assemble, adjust and disassemble.

What Are Non-Threaded Fasteners?

These fixtures lack helical threads. Instead, they rely on different mechanisms like expansion, interference fits or locking mechanisms to secure components together. They’re used in situations where future disassembly isn’t required or where the material is unsuitable for threaded fasteners.

Types of Threaded Fasteners 

Standard threaded fasteners include screws, nuts and bolts. Each one contains different subtypes that make them more suited for specific applications.

The Essential Guide to Threaded Fasteners: Screws, Nuts and Bolts


Screws have external spiral grooves and a pointed end to dig and penetrate into the material. They’re designed to be turned — usually with a screwdriver — to form a secure grip.

Different threaded screw types include:

  • Cap screws: Cap screws have thick, wide heads with flat bottoms facing the pointed ends.
  • Machine screws: These screws are designed with finer and more accurate threads to fasten various types of metal parts together.
  • Security screws: Also known as tamper-proof or anti-temper screws, this type features a special head that makes it harder to remove.
  • Tapping screws: Tapping screws create threads in the materials they’re turned into, which makes them ideal for disassembling and reassembling products.
  • Socket screws: Designed with a hexagonal internal drive in the head, socket screws can only be tightened and loosened with specific wrenches or hex keys as opposed to a screwdriver.
  • Construction screws: These screws offer corrosion resistance and durability, making them ideal for use on construction sites where performance is required.
  • Metric screws: A metric screw’s size is specified using the metric system — in millimeters.


A threaded bolt is a fastener that contains threads at one end and a head at the other. It’s similar to a screw. However, the thread of a bolt is designed to be used with a nut so it can fasten two or more components together. Where screws are not meant to pass a piece of material completely, bolts need to make a connection with a nut. In some cases, bolts are fastened with washers to distribute loads evenly while tightening the bolt.

Screws are best for lighter applications, while bolts are more suited for heavy-duty projects. Different types of bolts are applied in various industries.

  • Tension control bolts: These three-piece preassembled bolts are often used in steel frame construction and require a dual socket electric wrench to install. Tension control bolts consist of a hardened flat washer, 12-point spline and heavy hex nut. During installation, the inner socket grips the spline to hold the bolt in position while the external socket turns the nut. The spline shears off when it reaches the torque coefficient, leaving the nut and bolt to maintain the structural integrity of the connection.
  • Structural bolts: Structural bolts often have hex-style heads and are made for heavy-duty structures, such as buildings and bridges. They tend to be larger in size than finished hex bolts with the same-sized flats. These bolts are ideal for high-pressure or high-temperature applications. Both steel and alloy steel structural bolts must follow specifications under ASTM guidelines. 


Nuts are small circular or hex-shaped objects with a round hole in the center that matches the thread of a bolt. They are screwed onto bolts to help hold materials together.

Various types of nuts exist, making them ideal for many applications. These are some of the most common nut types:

  • Hex nuts: Most nuts have six sides, making them easy to grip and install or remove without much effort.
  • Flange nuts: Flange nuts are often used on automotive exhausts and play the same role as a washer.
  • Slotted nuts: These nuts are used to prevent rotation in applications with constant vibrations, secured with a cotter pin or wire.
  • Wing nuts: These nuts come with side wings that enable quick and easy tightening and loosening by hand.
  • Dome nuts: These nuts form a protective dome over bolt threads, preventing sharp edges from sticking out.

Frequently Asked Questions

Have further questions about fasteners? Check out a few answers to FAQs below.

What Factors Should Be Considered When Choosing a Fastener? 

When selecting any type of fastener for your next project, consider the following factors:

  • Material: Knowing where and how you will use fasteners can help you determine the right type of material and coating for them. Some materials and coatings are stronger and more durable in specific conditions.
  • Strength: Bolts tend to be stronger than screws due to the help of nuts. You can reference the ASTM fastener standards for more information on fastener strength.
  • Cost: Custom fasteners are more costly than generic fasteners. However, the right fasteners should ensure your product’s reliability and success, and custom fasteners may be needed to meet unique product specifications.
  • Size and shape: Most fasteners come in a variety of industry-standard shapes and sizes. Heavy-duty applications normally need larger fasteners, while projects with tighter designs need smaller fasteners.

What Are the Qualities of Good Fasteners? 

The Essential Guide to Threaded Fasteners: Screws, Nuts and Bolts

The best fasteners will meet high safety standards following industry guidelines and feature coatings that protect against corrosion and wear and tear. Specifically, the highest quality fasteners for your project will be the ones that are also the correct shape for your tools.

What Are the Common Materials Used in Threaded Fasteners?

Some of the most common materials used in threaded fasteners include:

  • Steel: Most fasteners are made of steel, including stainless steel and alloy steel, for its tensile strength and durability.
  • Bronze: Bronze fasteners can withstand highly corrosive environments.
  • Aluminum: Fasteners made from aluminum are resistant to corrosion and lightweight.
  • Nylon: Nylon fasteners are lightweight, like aluminum fasteners, with the added advantage of being electrical insulators.
The Essential Guide to Threaded Fasteners: Screws, Nuts and Bolts The Essential Guide to Threaded Fasteners: Screws, Nuts and Bolts

Contact C.M. Mockbee Co. for Custom Threaded Products

C.M. Mockbee Co. specializes in the production of custom-threaded products. For more than a century, we’ve offered reliable manufacturing capabilities for customers just like you. Thanks to our high-speed roll threading machines, we can address the specific needs and applications within your industry with quick lead times.

Our team provides amazing one-on-one attention to all customers, along with the capacity to handle projects of all sizes. To find out more about our threaded products, our large portfolio of fasteners and anchoring products or custom solutions and capabilities for your organization, request a quote today. We’ll be in touch soon.

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The Essential Guide to Threaded Fasteners: Screws, Nuts and Bolts
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