Cap Screw vs Set Screw – What’s the Difference

Cap Screw VS Set Screw

There are many options to choose from when it comes to fastening parts together. Two of the most commonly used fasteners are cap screws and set screws. While they may look similar, they serve different purposes and have unique characteristics. Understanding the difference between the two will help you choose the right type of fastener for your project. In this blog post, we will explore the difference between cap screws and set screws.

What is Cap Screw?

Cap screws are also referred to as machine screws or hex bolts. They come with a hex head and a threaded shank that runs the length of the screw. Cap screws are available in different lengths, diameters, and materials and are used to fasten metal parts together. The hex head is designed to be tightened with a wrench, providing additional torque and resistance to loosening. Cap screws are ideal for secure and strong fastening applications, such as automotive, construction, and industrial machinery.

What is Set Screw?

Set screws, on the other hand, are small screws that are used to secure a component onto a shaft. They do not have a head like a cap screw but instead have a threaded shaft that is screwed directly into the component. Set screws are commonly used in applications where there is no need for additional torque or where there is not enough space for a cap screw. They are designed to seat flush with the component’s surface and provide a secure, low-profile fastening. Set screws are commonly used in electronics, woodworking, and small machinery applications.

Difference Between Cap Screw and Set Screw

A cap screw is a machine fastener with a threaded shaft and hexagonal head to fasten different parts together. A set screw is an unthreaded cylindrical component that sits in a pre-drilled hole and is tightened into the mating part with a hex key. The main difference lies in the threads: cap screws have threads, while set screws do not. This distinction allows for better tightening strength and more flexibility when it comes to customization.

Thread Types

One of the main differences between cap screws and set screws is the type of thread they have. Cap screws have a fully threaded shank, which means the threads run the length of the screw. This provides maximum grip and holding power when threaded into a component. Set screws, on the other hand, have a partial thread that only runs a portion of the length of the screw.

Material and Strength

Cap screws are made from various materials, including steel, stainless steel, and titanium. They are known for their high strength, durability, and resistance to corrosion. Set screws are typically made from steel, brass, or aluminium. They have lower strength than cap screws but can still provide sufficient holding power for their intended applications. Choosing the right material and strength for your application ensures a secure and long-lasting fastening.

Size and Appearance

Cap screws come in various sizes and diameters, and the hex head design provides a uniform appearance once fastened. Set screws are smaller, typically cylindrical, with a hex socket or slotted head. The lack of a head gives set screws a low-profile appearance that is often desired in certain applications.


In conclusion, the main difference between cap screws and set screws is their design and intended application. Cap screws provide a strong and secure fastening where additional torque is required, while set screws provide a low-profile and flush fastening. Understanding the differences between the two will help you choose the right type of fastener for your project to ensure a stable and long-lasting result. So, next time you are working on a project, remember the differences between cap screws and set screws so that choosing the right one is a breeze.



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