Best Structural Bolts of 2025

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Structural bolts are an essential component in construction projects, providing a secure and reliable connection between structural steel members. These heavy-duty bolts are designed to withstand high loads and are commonly used in bridges, buildings, and other large-scale structures. Structural bolts come in various sizes and grades, each with specific strength and durability characteristics. They are typically made from high-strength materials such as carbon steel or alloy steel and are often coated with a protective layer to prevent corrosion. The use of structural bolts can help to ensure the safety and stability of a structure, making them an essential component in construction projects.
At a Glance: Our Top Picks
Top 10 Structural Bolts
Samac High Performance Structural Wood Screws
The Samac Structural Wood Screws are designed for high performance with a hex drive, making them easy to apply. With up to 1000 hours of salt spray resistance, they offer exceptional durability, ensuring your projects withstand the elements. You will appreciate the included 65mm driver hex head socket for effortless installation. Furthermore, these screws often eliminate the need for pre-drilling in most timbers, saving you time and effort during your woodworking tasks.
High Performance Structural Wood Screws 6.7 x 200mm
The Samac Structural Wood Screws are designed for high performance in timber applications. The hex drive allows for easy installation, ensuring you can securely fasten timber with ease. The Type 17 point helps to reduce drive torque, making your work smoother and less labour-intensive. Additionally, the extremely sharp piercing point means you can penetrate wood effortlessly, while the specially designed serrated milling thread provides a strong grip, enhancing overall stability. Each box comes with a convenient 65mm driver hex head socket for added user-friendliness.
M5 Pozi Pan Head Machine Screws Pack
The RC Screws M5 Screws are designed with a 5mm thread size and a thread length of 20mm, ensuring a secure fit for your projects. The head diameter of 10mm provides stability, making these screws ideal for various structural applications. With a head length of 3.95mm, they are easy to drive into materials without excessive protrusion. Made from A2 grade stainless steel, these screws offer excellent corrosion resistance, ensuring durability and longevity in both indoor and outdoor conditions.
M3 x 30 Brass Slotted Pan Machine Screws
The Singularity Supplies Screws are designed with a slotted pan head, making them easy to tighten and loosen with standard tools. These machine screws measure 3mm by 30mm, ensuring they are suitable for a variety of applications. Made from durable brass, they offer resistance to corrosion, enhancing the longevity of your projects. With a tolerance that meets ISO 965 standards, you can be assured of their reliability in structural tasks.
M6 Stainless Steel Slot Pan Machine Screw
The M6 Slot Pan Screw is designed for a variety of structural applications. Its slotted pan head allows for easy installation, making it convenient for you to secure components without hassle. Being a machine screw, it provides strong fastening capabilities, ensuring your projects remain stable and reliable. Made from high-quality stainless steel (A2), this screw is resistant to corrosion, which extends its lifespan and maintains its appearance. With a metric measurement, it fits seamlessly into standardised projects, enhancing your building experience.
M6 Stainless Steel Screws and Bolts Kit
The M6 Bolts and Nuts Kit is an essential assortment for anyone needing reliable fasteners. With 15 pieces of M6X10 screws, 10 pieces each of M6X20, M6X30, and M6X40 screws, plus 45 matching nuts, this kit provides a comprehensive solution for various applications. Made from 304 stainless steel, it offers excellent corrosion resistance, ensuring durability in different environments. The deep threads and uniform tooth distance allow for secure fastening, making your tasks easier and more efficient. This kit is ideal for automotive, maritime, and home office repairs.
M5 Stainless Steel Slotted Pan Screws Pack of 20
The M5 Slotted Pan Screws are designed to offer exceptional durability and reliability for your projects. With a slotted pan head type, you can easily use a flathead screwdriver for installation, ensuring a secure fit. Made from stainless steel (A2), these screws resist corrosion, making them ideal for outdoor applications. Their metric measurement guarantees compatibility with various components, while adhering to ISO 965 standards ensures high-quality tolerance. This combination of features allows you to complete your tasks confidently and efficiently.
M4 Stainless Steel Screws and Nuts Kit
The M4 Nuts and Bolts Kit offers a versatile assortment of 135 screws and 135 nuts in various sizes, including M410 to M430. Made from durable 304 stainless steel, it boasts excellent corrosion resistance, ensuring longevity for your projects. The deep threads and uniform tooth distance provide reliable fastening, making it easy for you to secure different components. This kit is ideal for replacing parts in automobiles, ships, and home offices, catering to both DIY enthusiasts and professionals alike.
M5 Pozi Pan Steel Machine Screws - Pack of 20
The M5 Steel Machine Screws are designed with a Pozi Pan head type, ensuring a secure grip for easy installation. Made from durable steel, they provide strength and reliability for various applications. The metric measurements make them suitable for standardised projects. Additionally, the corrosion-retardant zinc plating protects against rust, which enhances their longevity and performance in different environments. These features combined ensure that you can complete your tasks with confidence and ease.
M6 Slotted Mushroom Machine Screws - Pack of 20
The Singularity Supplies Screws are designed with a slotted mushroom head, making them easy to drive and adjust with a standard screwdriver. These machine screws are manufactured to metric measurements, ensuring they fit perfectly in various applications. Crafted from high-quality stainless steel (A2), they offer excellent corrosion resistance, which is beneficial for outdoor or damp environments. Additionally, they adhere to ISO 965 standards, providing reliable performance and precision in structural applications. You'll appreciate the convenience and durability these screws bring to your projects.
Frequently Asked Questions (FAQs)
1. Which type of bolt is a structural bolt?
ASTM A325 structural bolts are heavy hex bolts made of medium carbon steel with a flat bearing surface, washer faced, and chamfered point. They are commonly used in structural steel joints in heavy construction and available in diameters ranging from 1/2” up to 1-1/2”.
2. What are structural bolts used for?
Often used in structural steel to steel fastening applications, the structural bolt is a hex head style threaded fastener designed to provide the heavy duty holds needed in steel building frameworks. The heavy hex head of the bolt gives this fastener a wider bearing surface to distribute the load better.
3. Why are structural bolts installed up and out?
A: Traditionally the bolt stick-out through the nut has been an indicator that the correct length of bolt has been selected for a connection and to verify that the nut will not bottom out at the end of the threads during tensioning. The stick-out can be used as an inspection tool.
During our structural bolt research, we found 123 structural bolt products and shortlisted 10 quality products. We collected and analyzed 5,663 customer reviews through our big data system to write the structural bolts list. We found that most customers choose structural bolts with an average price of £6.06.
The structural bolts are available for purchase. We have researched hundreds of brands and picked the top brands of structural bolts, including Samac, RC Screws, Singularity Supplies, omyzam. The seller of top 1 product has received honest feedback from 63 consumers with an average rating of 4.3.

Corey Philips is an electrician and lighting expert. He graduated from the University of Birmingham in 2012 with a Bachelor's degree in electrical and electronics engineering. Corey is a specialist contractor in lights. He sells and installs and recommends lights and lamp sheds, and other lights accessories. Aside from that, Corey is vast in installing and maintaining electrical appliances like air conditioners, water heaters, and the likes.