Self Tapping vs Machine Screw – What’s the Difference

Self Tapping vs Machine Screw

There are many options when it comes to fastening two pieces of material together. Two of the most popular options are self-tapping screws and machine screws. While these screws may look similar, they have different functions and uses. Understanding their differences can help you choose the right one for your projects. In this blog post, we will explore the differences between self-tapping screws and machine screws.

Self Tapping Screw

A self-tapping screw has a unique design allows it to create its threads when driven into the material. This screw is commonly used in materials such as wood or plastic, where it is necessary to create threads within the material itself.

Machine Screw

A machine screw requires an existing thread to be present in the material to be fastened. This type of screw is often used in metal or other hard materials that can easily be threaded.

Difference Between Self-Tapping and Machine Screw

Self-tapping screws are designed to create their mating thread on installation, while machine screws require a separate nut or tapped hole for installation. Self-tapping screw styles include wood and sheet metal threads, sealing and non-sealing versions, and even hardened varieties. Machine screws come in various materials like steel, brass and stainless steel with various finishes. Both self-tapping and machine screws offer great versatility when used properly, depending on the application & material being fastened.


The primary difference between self-tapping and machine screws is the type of threads used. Self-tapping screws have a special thread design that allows them to cut their thread into the material they are being driven into. Machine screws, on the other hand, have a standard thread design that requires pre-tapped holes to be installed properly.

Head Types

Another difference between self-tapping and machine screws is the type of head used. Self-tapping screws typically have a pan or truss head, whereas machine screws usually have a flat or oval head. The head’s shape helps determine how much torque can be applied when driving the screw into place.


Self-tapping and machine screws are also available in different materials, such as steel, stainless steel, brass, and aluminium. The material used will depend on the application and the type of strength needed for the job. Generally speaking, steel is stronger than aluminium but may rust if exposed to certain elements over time. Stainless steel offers better corrosion resistance but is more expensive than other materials.

Drive Types

Self-tapping and machine screws also come in different drive types, such as Phillips, slotted, Torx®, hex sockets, and square drive heads. The drive type chosen will depend on the application and whether a power tool or manual tool will be used for installation purposes. Phillips’s heads are the most common drive type for self-tapping and machine screws due to their ease of use with manual and power tools.


The cost of self-tapping and machine screws can vary depending on size, material, drive type, quantity purchased, etc. Generally speaking, self-tapping screws tend to be more expensive than machine screws due to their specialized thread design, which requires additional manufacturing steps for them to function properly.


Self-tapping screws and machine screws may look similar, but they have distinct differences that make one suitable for certain applications over the other. Now that you understand the differences between these two screws, you can choose the right type for your projects. Whether you need to fasten materials together in a wooden frame or a metal structure, you can select the perfect screw by considering the material type, screw size, and installation requirements. Always choose the right screw to keep your projects strong and durable.



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