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8 Types of Hex Screws and Their Uses

Hex Screws

Hex screws are among the most popular types of screws used in different applications, from construction to DIY projects. Unlike other screw types, hex screws have a hexagonal shape, providing a perfect grip for tightening or loosening them. These screws vary in size, material, and design, making choosing the right type for your specific project essential. In this guide, we look at the different types of hex screws, their uses, and the benefits of each kind.

Types of Hex Screws

Hex Head Bolts

Hex head bolts are among the most common types of hex screws. These screws have a hexagonal head and come in various sizes, materials, and finishes. Hex bolts are typically used in applications requiring high strength, such as in construction, machinery, and automotive projects. They are sturdy and durable, making them ideal for projects requiring permanent fastening. Hex head bolts come with different thread pitches, and you should choose the right one, depending on the application.

Socket Head Cap Screws

Socket head cap screws, or Allen bolts, are hex screws with a flat head and a cylindrical body. Unlike hex bolts, socket head cap screws have a flush head, ideal for applications requiring a smooth finish. These screws are commonly used in bicycles, motorcycles, and consumer electronics, among other applications. They are available in different thread sizes and lengths, making them ideal for varied projects.

Lag Screws

Lag screws, also known as coach screws, are hex screws that are larger and are commonly used in wood and metal applications. They have a thick, coarse thread designed to grip the material to prevent it from stripping out. Lag screws are perfect for construction projects requiring a sturdy fastening solution. They are ideal for use in outdoor projects as they are resistant to corrosion and rusting.

Self-drilling Hex Screws

Self-drilling hex screws are fasteners that drill and tap their hole as they are being screwed in. This type of screw comes with a hexagonal head that provides additional torque and stability when tightening the screw. They are commonly used for metal-to-metal applications and are especially popular in the construction and automotive industries. Incorporating a hexagon head design into the self-drilling features makes these screws a top choice among professionals for their strength, durability, and ease of installation.

Button Head Cap Screws

Button head cap screws have a round, domed head and a hexagonal body. These screws are ideal for use in applications where a decorative finish is required, as they provide a clean and polished look. They are commonly used in furniture making, automotive, and consumer electronics, among other applications. Button head cap screws come in different materials, finishes, and colours, making them ideal for various projects.

Internal Hex Screws

Internal hex screws are a fastener commonly used in various applications, including those in the medical, dental, and manufacturing industries. They feature a hexagonal-shaped recess in the head, allowing easy tightening and loosening with a matching hexagonal wrench or driver. These screws are known for their reliability and strength, making them popular for applications where stability is crucial.

Set Screws

Set screws are hex screws used to secure shafts or gears onto machinery or mechanical parts. They are usually small and available in different lengths and thread sizes. Set screws are versatile and are commonly used in aerospace, automotive, and manufacturing industries. They can be made of other materials, such as steel or brass.

Combi Screws

Combi screws are an innovative solution for both wood and metal fastening. These unique screws have a combination of thread types on the shaft to allow for easy installation in both materials. The Wood thread ensures a secure grip on wooden materials, while the machine thread provides a stable hold on metal surfaces. The Combi screw’s versatility makes it a reliable option for projects with different materials.


When it comes to choosing the suitable hex screws, it all boils down to the project requirements. The type of hex screw you choose largely depends on the material you are fastening, the application and the required load capacity. From hex head bolts to button head cap screws, each type of hex screw has unique characteristics that make it ideal for specific projects. By understanding the different types of hex screws and their uses, you can choose the correct fasteners for your project and achieve the best results.

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