Half threaded hex bolts are a versatile and widely used fastener in the hardware industry. Known for their unique design, these bolts feature a partially threaded shank and a hexagonal head, making them ideal for applications requiring both strength and precision. But what exactly are half threaded hex bolts called, and why are they so popular in construction, automotive, and industrial settings?

In this article, we’ll explore the technical name for half threaded hex bolts, their key features, and their applications. We’ll also discuss the benefits of using these bolts and provide insights into their specifications and installation methods. By the end, you’ll have a comprehensive understanding of why these fasteners are a go-to choice for engineers and DIY enthusiasts alike.

What Are Half Threaded Hex Bolts Called?

Half threaded hex bolts are commonly referred to as "partially threaded hex bolts" or "tap bolts." These terms describe their design, which includes a threaded portion at the end of the shank and an unthreaded portion closer to the head. The unthreaded section provides added strength and stability, while the threaded end allows for secure fastening.

In some regions, they are also called "dowel bolts" or "shoulder bolts," especially when used in alignment or positioning applications. Regardless of the name, these bolts are recognized for their durability and versatility.

Key Features of Half Threaded Hex Bolts

Half threaded hex bolts are designed to meet specific performance requirements. Here are their key features:

1. Hexagonal Head: The six-sided head allows for easy tightening and loosening using a wrench or socket.

2. Partially Threaded Shank: The threaded portion is typically 1.5 to 2 times the bolt diameter, while the unthreaded section provides shear strength.

3. Material Options: These bolts are available in various materials, including carbon steel, stainless steel, and alloy steel, to suit different environments.

4. Coatings and Finishes: Common finishes include zinc plating, hot-dip galvanizing, and black oxide, which enhance corrosion resistance.

5. DIN/ANSI/ISO Compliance: Manufactured to international standards, ensuring compatibility and reliability.

Applications of Half Threaded Hex Bolts

Half threaded hex bolts are used in a wide range of industries due to their unique design and strength. Here are some common applications:

1. Construction Projects
In construction, these bolts are used to connect structural components, such as steel beams and concrete forms. The unthreaded section provides additional shear strength, making them ideal for load-bearing applications.

2. Automotive Industry
Half threaded hex bolts are commonly used in vehicle assembly, particularly for securing engine components, suspension systems, and chassis parts. Their durability ensures long-lasting performance under high stress and vibration.

3. Machinery and Equipment
In industrial machinery, these bolts are used to assemble heavy equipment, conveyor systems, and hydraulic presses. The partially threaded design allows for precise alignment and secure fastening.

4. DIY and Home Improvement
For DIY enthusiasts, half threaded hex bolts are a reliable choice for building furniture, installing shelves, or repairing outdoor structures. Their versatility makes them suitable for both indoor and outdoor use.

Advantages of Using Half Threaded Hex Bolts

Why choose half threaded hex bolts over fully threaded alternatives? Here are some of their key benefits:

1. Increased Shear Strength: The unthreaded section provides greater resistance to lateral forces, making them ideal for structural applications.

2. Easier Alignment: The smooth shank allows for easier alignment of components during assembly.

3. Reduced Thread Damage: The partially threaded design minimizes wear and tear on the threads, extending the bolt’s lifespan.

4. Versatility: Suitable for a wide range of materials, including metal, wood, and plastic.

5. Cost-Effective: Their durability and reusability make them a cost-effective choice for long-term projects.

How to Choose the Right Half Threaded Hex Bolt

Selecting the right bolt for your project involves considering several factors:

1. Material: Choose a material that matches the environmental conditions (e.g., stainless steel for corrosive environments).

2. Size and Length: Ensure the bolt length is appropriate for the thickness of the materials being joined.

3. Thread Pitch: Match the thread pitch to the corresponding nut or tapped hole.

4. Finish: Select a finish that provides the necessary corrosion resistance and aesthetic appeal.

5. Standards Compliance: Verify that the bolts meet DIN, ANSI, or ISO standards for quality assurance.

Installation Tips for Half Threaded Hex Bolts

Proper installation is crucial to ensure the performance and longevity of half threaded hex bolts. Follow these tips:

• Use the correct size wrench or socket to avoid stripping the hex head.

• Apply a thread-locking compound if the bolt will be exposed to vibration.

• Tighten the bolt to the recommended torque specification using a torque wrench.

• Inspect the bolt periodically for signs of wear or corrosion.

Conclusion

Half threaded hex bolts, also known as partially threaded hex bolts or tap bolts, are an essential fastener in various industries. Their unique design, combining a threaded end with an unthreaded shank, provides exceptional strength and versatility. Whether you’re working on a construction project, assembling machinery, or tackling a DIY task, these bolts offer reliable performance and durability.