Common Fastener Heads For A Screw Or Bolt

Introduction

Choosing the right head for your fastener is crucial to the success of any project. With so many different options and applications available, it can be overwhelming to make the right choice. In this guide, we will explore the various types of fastener heads and their uses, providing you with the knowledge to select the perfect head style for your needs.

The Importance of Fastener Heads

The head of a fastener is the area that contains the drive, which is used to install the screw or bolt. It acts as the clamping point between the fastener and the workpiece. Not only does the head play a critical role in the anatomy of a screw, but it also determines the length and strength of the fastener. Additionally, the head is often the only visible part of the fastener after installation.

Fastener Head Types

There is a wide array of head types available for fasteners, each with its own common use and advantages. It’s essential to understand the different head styles and their applications to choose the right one for your project. Let’s explore some of the most commonly used fastener head types:

Binding Undercut Head

The binding undercut head is frequently used in electrical applications. It features a channel that allows for the incorporation of electrical wires underneath the head, ensuring secure connections and increased electrical conductivity. This head can be utilized with Phillips, slotted, and combination drives.

Bugle Head

The bugle head, named after the bugle horn, is commonly used in wood decking and drywall screws. It boasts a countersunk head style and is ideally suited for “softer” materials. The tapered wedge of the bugle head provides a self-made countersink without the need for additional tools. This head applies more downward clamping force, thanks to its wider face, and can be used with Phillips, slotted, and 6 Lobe drives.

Fillister Head

The fillister head has a deep slotted profile, offering a higher profile than round or pan heads. It can be used with Phillips or slotted drives and is often favored for its versatility in various applications.

82° Flat Head

The 82° flat head, also known as the standard flat head (90° flat in metric), is prevalent in both metal and wood applications. It provides a “flush” or smooth finish, making it ideal for aesthetic and decorative purposes. This head style can be used with Phillips, slotted, 6 lobe, Pozi, and square drives. Unlike the bugle head, the flat head requires pre-drilling before installation.

82° Flat Undercut Head

Similar to the standard flat head, the 82° flat undercut head features an undercut that allows for a smaller countersunk area. It is commonly used in thin sheet metal applications, particularly in door hinges. This head style has no metric standard and provides a sleek appearance.

100° Flat Head

The 100° flat head offers an alternative to the standard 82° flat head, with a larger head diameter and a 100° angle. This head style is commonly used for thinner materials, providing excellent surface area contact without sacrificing strength. It is available with various drive options but is only available in 90° flat as the metric equivalent.

Hex Head

Hex heads are commonly found in bolts and provide a large surface area for torque application. The hexagonal shape allows for a significant amount of force to be applied, making it ideal for high-torque applications. This drive requires the use of a wrench or socket. Hex cap bolts have a washer bearing surface under the hex head to keep it perpendicular when tightened.

Hex Washer Head

The hex washer head is a popular choice, offering the same advantages as the hex head but with the addition of a washer-style flange. This flange provides a larger bearing surface, distributing the load of the fastener and preventing marring of the workpiece surface. The hex portion of the head allows for the use of secondary drives such as combination, slotted, and Phillips.

Oval Head

The oval head is similar to the flat head but features a domed oval section on top. This head style creates a finished and aesthetic look, sitting proud of the workpiece when seated. It can be used with Phillips, slotted, and 6 Lobe drives, making it versatile for various applications.

Oval Undercut Head

Similar to the standard oval head, the oval undercut head includes an undercut for shallower countersunk depths. It offers the same finished appearance but with the added advantage of a reduced countersunk area. This head style is commonly used for thin sheet metal applications and is a popular choice for electrical outlet covers.

Pan Head

The pan head is the most common rounded head style, featuring a relatively small profile. It is commonly used in mounting brackets and hardware applications. The pan head can be substituted for round, truss, or binding heads due to its smaller outer diameter. It can be used with Phillips, slotted, 6 lobe, and combination drives, providing versatility and ease of use.

Round Head

The round head is a versatile option that can be used in a variety of applications. It is often used as an alternative to the oval head, offering a finished look without the need for countersinks. This head style is commonly used in electrical applications and can be used with Phillips, slotted, U-drive, and combination drives.

Round Washer Head

Similar to round heads, the round washer head features a washer-style flange attached to the bottom of the head. This design allows for more distributed loading and less stress on the head of the fastener. The washer also provides a finished aesthetic look, making it ideal for various applications.

Serrated Heads

Hex washer, pan, and truss heads can be equipped with serrations under the head. These serrations prevent loosening and backing out, making them suitable for high-vibration applications. Serrated heads offer enhanced security and peace of mind, ensuring that your fasteners stay in place.

Trim Head

The trim head is specially designed for finishing work, featuring a narrower head for a less visible appearance after installation. It is commonly used in woodworking projects and carpentry applications. This head style can be used with Phillips, square, and 6 Lobe drives.

Truss Head

The truss head, also known as a “mushroom” head, provides an increase in bearing surface without significantly increasing the profile. It offers a larger bearing surface than round heads, providing greater clamp force. While weaker than pan or round heads, the truss head is ideal for applications with minimal clearance. It can be used with Phillips, slotted, 6 Lobe, and combination drives.

Modified Truss Head

The modified truss head features a larger head diameter and lower profile than the standard truss head. Similar to the truss head, it also has a washer-style flange for increased bearing surface contact. This head style is often found on self-drilling screws used to attach metal lathe to metal studs.

Wafer Head

The wafer head is commonly used in self-drilling screws and features a countersunk design with a bearing surface. It sits flush with the workpiece surface, ensuring even load distribution. This head style is ideal for wood and softer materials and can be used with Phillips, slotted, 6 Lobe, and combination drives.

Conclusion

Choosing the right head style for your fasteners is essential for the success of your project. Consider factors such as aesthetics, strength, length, and functionality when making your decision. By understanding the different head types and their applications, you can make an informed choice for your specific needs. Now, armed with this knowledge, let’s get building!

References:

• Image Source
• Spec Sheet