You’ve probably stood in front of a confusing display of screws in your local DIY store and tried to figure out which one is best for your project.
You’re not the only one. Fasteners may be difficult to understand, but the first step to becoming an expert at any home improvement project is to educate yourself on the many types of screw heads. The right screw head can make a big difference when assembling furniture or building a home.
This guide will help you with that. We’ll show you the many types of screw heads, explain what characterises each one and show you where you can use them.
By the end, you’ll know exactly which screw to use for each project, so you can be sure the result will always look professional and secure.
What is a Screw Head?
What actually is a screw head? The screw head is the part of the screw that has a specific shape and drive type. You need a tool, e.g. a spanner or a screwdriver, to turn the screw and screw it into something. The design of the head is not just for looks. It is essential.
The shape of the head affects how the force is distributed when you drive the screw in. Some heads are designed to lie flat on the surface for a flawless finish, while others remain raised.
The type of head will also determine what type of screwdriver you need, from a simple flat head to a more sophisticated star-shaped one. It’s important to choose the right screw head to ensure the joint is strong and durable.
Basic Screw Anatomy
It’s easier to understand screws when you know what their main components are. When you know what they do, it’s easier to work with them than when you’re getting to know a new colleague. Each part of a screw has a specific task to fulfil, and when they all work together, they make a strong and flexible fastener.
Drive
A screw drive is the recess or protrusion on the head of a screw that allows it to be turned by a corresponding tool, such as a screwdriver or bit.
Head
The head is the top part of the screw, as you have just learnt. This is the part you will get to know best because this is where your tool comes into play. There are many different shapes and sizes of heads, each designed for a specific task. The design of the head is very important for a project to be successful. It can be anything from a simple flat head to a more complex truss head.
Shank
The shank is the part of the screw that is smooth and unthreaded. It is located directly below the head. Some screws have no shank; the thread goes all the way to the head. The shank is designed to slide through the face material so that it can be pressed firmly against the material to which it is to be fastened. This is particularly useful in woodworking, where a tight fit is very important.
Thread
The thread is the sharp, spiral-shaped ridge that runs around the body of the screw. This is the actual task: it cuts into the material and holds the screw in place. The angle and spacing of the thread can vary depending on the intended use of the screw. Screws for softwoods, for example, have a coarser thread than screws for hardwoods.
Tip (point)
The tip is the part of the screw that does the work. This is the component that goes into the substance first. Some screws have a sharp tip that helps them start the hole and keep the screw straight. Others have a blunt or flat tip, which is typically used on holes that have already been drilled. The type of point you need depends on what you are dealing with and whether you are drilling a pilot hole.
Common Types of Screw Heads
Now that you know the basic parts of a screw, let’s take a look at the most common types of screw heads you’ll come across. Knowing the differences will help you choose the right tool for the job, as each screw head is designed for a different purpose.
1. Flat Head Screws (Countersunk Head)
A flat-head screw has a flat top and a tapered bottom. This design allows the screw to be flush with the surface. This is why it is also called a countersunk head. For this reason, it is a popular option for woodworking and cabinets where a smooth, undamaged surface is required. You usually get them with a countersunk hole that fits perfectly.
2. Flange Head Screws
A washer or flange is incorporated into the head of a flange head screw. This flange distributes the weight over a larger area, preventing the screw from pushing through the material. This makes it a fantastic option for holding thin objects together, such as sheet metal. The large contact surface on the underside gives it great holding power.
3. Binding Head Screws
Binding head screws or binding head screws have a thick, spherical head with a slightly rounded top. As they have a deep slot, they are easy to screw in. Due to the undercut under the head, they are often used for electrical work as they make it easier to hold wires in place.
4. Bugle Head Screws
U-head screws are a type of countersunk head screw, but their heads are bent and shaped like a U-horn. This unusual shape helps to ensure that the fabric you are fastening is not damaged. You often see these screws on plasterboard because the curved head allows the screw to penetrate the paper without tearing it. The shape of the ironing head is ideal for soft textiles.
5. Dome Head Screws
As the name suggests, screws with a domed head have a smooth and rounded head. These screws are often used in places where the head is visible because they look nice and complete. They are typically found on licence plates and in furniture construction. The rounded head gives them a modern and streamlined look.
6. Raised Head Screws
It has a countersunk base and a slightly rounded head, which makes it a kind of hermaphrodite. As a result, it sits slightly recessed in the material, with the tip of the head protruding just above the surface. This design gives it a decorative touch and is normally used to attach knobs and handles to furniture.
7. Truss Head Screws
Phillips head screws have a wide, flat head that is rounded at the top. This head is unusually wide, allowing the weight to be distributed well. This makes them ideal for holding thin materials together or for spanning a large hole. Truss-head bolts are generally used for joining rolls and for processing sheet metal.
8. Combination Head Screws
Combination screws are the best of all worlds because you can use either a slotted or Phillips screwdriver to drive the head. Therefore, they can be used in many different ways, making them a great option. A combination screw is a safe choice if you are not sure which type of screwdriver you will have to hand.
9. Pin-in Head Screws
Screws with a pin in the head are a type of security screw that prevents anyone from tampering with them. There is a small pin in the centre of the screw head, which makes it necessary to use a special tool to screw them in or take them out. As they are difficult to tamper with, they are ideal for use in public facilities such as signs and public toilets.
10. Sentinel Head Screws
Sentinel head screws are another type of security screw that is difficult to tamper with. Their drive design is unique and patented, so you need a special screwdriver bit to use them. For this reason, they are a popular option for places where security is very important, such as prisons or military facilities.
11. Two-Hole Head (Spanner Head)
Bolts with two-hole heads have two small holes in the head, also known as spanners or snake-eye bolts. To turn them, however, you need a special spanner. Due to their strange shape, they cannot be replaced. You often see them in public places such as parks and on public transport.
12. Triangular Recess Head Screws
The head of a screw with a triangular slotted head has a triangular hole. This is another type of security screw as it requires a special triangular spanner to turn it. You can use them in many different places where you don’t want others to get in without authorisation, e.g. on electrical appliances or in cars.
13. Phillips Head (Cross Head)
The Phillips head, sometimes called a crosshead, is one of the most common screw heads you will see. It has a cross-shaped hole that makes it easier to grip than a slotted screw. This means you can apply a higher torque without the screwdriver slipping, known as “cam out” Phillips head screws are used for a variety of things, from electronics to construction.
14. Hex Socket Head Screws (Allen Head)
The head of hexagon socket screws, also known as Allen screws, has a hexagonal hole. To screw them in, you need an Allen key or a hexagon spanner. Due to their shape, a high level of tension can be applied, making them a popular option for assembling furniture and machinery. The hexagon socket gives you a strong and secure hold.
15. External Hex Screws
Hexagon head screws, often called external hexagon head screws, have heads that are shaped like hexagons so that you can hold them in place with a spanner or socket spanner. This allows you to apply a high torque, making them perfect for heavy-duty work. Hexagon head bolts are often used in the construction and automotive industries.
16. External Torx (Star) Head Screws
Screws with a star head, sometimes called external Torx screws, have a head that looks like a star and can be gripped with a special Torx insert. This design allows you to apply a high torque without the risk of jamming. They are often used in cars, especially on engine parts.
17. Pozidriv Head Screws
The Phillips head design has been improved with Pozidriv screws. There are small ribs on the top of the main cross that are at a 45-degree angle to it. This gives you a better grip and reduces the risk of unscrewing, even when the torque is high. Pozidriv screws are widely used in Europe and are often used when building and making things.
18. Quadrex Head Screws
A Phillips-style cross with a square hole in the centre makes up a screw with a Quadrex head. You can turn them with either a square or Phillips head screwdriver. They are popular for many different purposes as they are so versatile.
19. Slotted Head Screws
The slotted head screw is the first type of screw head and has a slot in the head. It is still commonly used, although it is more likely to break out than other designs. This means you can’t apply as much torque without the screwdriver slipping. Most people use slotted screws for easy woodwork and when they don’t need a lot of torque.
20. Square Recess Head Screws
Robertson screws, often referred to as square-head slotted screws, have a square hole in the head. This design makes it extremely difficult for the cam to come out and gives you a very tight grip. For this reason, they are a popular option for woodworking and construction, especially in Canada, where they were first manufactured.
21. Torx Head Screws
The head of a Torx screw, also known as a star screw, has a six-pointed, star-shaped hole. Thanks to this design, you can apply a high torque without the risk of distortion. Torx screws are widely used in the automotive and electronics industries as they ensure strong and secure connections.
22. Torx Plus (Enhanced Star Head)
Torx Plus is an improved version of the Torx design that has a more elliptical recess. This gives you an even stronger hold and allows you to apply more torque. Torx Plus screws are generally used in high-performance applications, e.g. in motorsport and aviation.
Frequently Asked Questions
Q: What are the different types of screw heads?
A: There are many different types of screw heads, and each has a specific shape and use. The most common include the flat head, the Phillips head, the Torx head and the hexagon head. It is important to choose the right head for your project, as each head is designed for a different purpose.
Q: Is Pozidriv better than Phillips?
A: Most people believe that the Pozidriv head is better than the Phillips head. The extra ribs on a Pozidriv screw make it easier to grip and reduce the risk of unscrewing, allowing you to apply a higher torque without the screwdriver slipping. This makes the Pozidriv screw a superior option for jobs that need high torque.
Q: Is a #10 or #8 screw bigger?
A: A #10 screw is larger than a #8 screw. There is a numbering system for screw sizes. The higher the number, the larger the diameter of the screw. A #10 screw has a larger diameter than a #8 screw.
Q: What are the six types of screws?
A: There are many different types of screws, but some of the most popular are wood screws, machine screws, lag screws, sheet metal screws, drywall screws and decking screws. These screws are all intended for different tasks and have their own special properties.
Conclusion
You now know everything you need to know about the different types of screw heads. As you can see, there is more to screws than meets the eye.
Every screw head, from the simple slotted head to the high-tech Torx Plus, is designed for a specific task.
You can choose the right screw for each job if you know the different types and their uses. This will ensure that the job is always done well and safely.
So the next time you go to the DIY store, you’ll know exactly which screw to buy.