Coarse Thread Vs. Fine Thread Fasteners

When you’re planning your next project, choosing the best fastener type is essential to the overall function of your final product. Coarse and fine thread screws are two specific fastener types that work well in various applications. The difference between fine and coarse thread screws can help you determine which one is right for your next project.

What Is a Coarse Thread Screw?

Coarse thread fasteners have a wider thread pitch — the distance between each row of threading. Since this pitch is wider, coarse thread screws have a low number of threads across the distance of the fastener.

Coarse threads allow more material to settle between the threading, making it harder for these screws to strip or cross thread. The threading can take on damage like nicks and marring and still function efficiently. Coarse threads are also less likely to gall or seize during tightening, making them easier to install.

What Are Fine Thread Screws?

In contrast, because of a narrow thread pitch, fine thread screws have a larger number of threads per distance. These threads offer higher tensile strength than coarse thread fasteners, and they’re often easier to tap. Since fine threading involves narrow, shallow ridges, there’s material to cut when forming threads.

Fine thread screws also have a shallow pitch or helical angle, making them more resistant to vibration. These fasteners also have less heft than their coarse counterparts, so they require less torque to install.

Which One Is Right for Your Application?

Choosing the right fastener for your application is about understanding the environment, the material and how the screw will need to perform.

Generally, coarse thread screws work well in most applications. These fasteners offer the strength and ease needed for many construction and industrial applications. Coarse threads work well with the following materials:

• Softwoods
• Plywood
• Oriented strand board (OSB)
• Wood studs

Fine threads are best for applications where vibration may be an issue. You’ll often find fine thread fasteners in machine parts, transmission parts and hydraulic systems because these applications involve high vibration. The materials best suited to fine thread screws include:

• Hardwood
• High gauge metals, including aluminum, titanium and stainless steel
• Metal studs
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