Self-drilling vs. self-tapping screws

When choosing the right screw for the job, many people get caught between self-tapping and self-drilling screws. 

Besides sounding similar, these screws offer some of the same benefits. Yet each one has a distinct purpose that helps when working on various projects. 

The difference between a self-tapping and a self-drilling screw can be the difference between a quick, clean finish and a frustrating afternoon of snapped bits. Today, we’ll break down exactly how these screws work, where to use them, and why choosing the correct one matters.

What is a self-drilling screw?

Self-drilling screws are among the most versatile screws available. With a sharp, drill-point head, they can drill into any material, even thick metal, without requiring a pilot hole. 

Since they don’t require a pilot hole, these screws save a lot of time (and money) when working on large projects, making them a popular choice for tradespeople. These are especially useful for jobs where you’re securing metal to metal or metal to timber. 

You’ll find them used for installing cladding, roofing sheets, steel framing, and sheet metal. Self-drilling screws come with drill point numbers. The higher the number, the thicker the metal it can drill through without pre-drilling. 

What exactly is a self-tapping screw?

Self-tapping screws are designed to tap their own mating threads as they drill into a surface. These screws can be used when working with wood, thin metal, or plastic.

Their unique thread design allows them to drill into a surface with ease; the screw’s thread either cuts into the material or forms the material into a matching thread as it goes. 

However, with self-tapping screws, you usually need to drill a pilot hole before inserting them into hard materials. Because the hole is slightly smaller than the screw, the threads cut into the material, creating a very tight bond. 

In the end, you’re left with a secure grip without the risk of the material splitting.

A quick comparison 

Which one should you choose?

You may have heard the saying, ‘self-drilling screws are always self-tapping screws, but not all self-tapping screws are self-drilling.’ 

What that essentially means is that, because many self-tapping screws don’t have a drill-bit tip, they still require a pilot hole, unlike self-drilling screws. However, all self-drilling screws still need to form/cut a thread as they drive in. That thread-making action is the “self-tapping” part.

There are also actually two types of self-tapping screws:

• Thread-cutting screws: these put less strain on the material, carving the material with their sharp edges to cut the thread. These require less effort on your part, but you’re left with metal or wood shavings coming out of the hole as you work.
• Thread-forming screws: they deform the material to form the thread, leaving no chips at the bottom for a clean finish (often used in plastics and thin metals). Since it compresses rather than cuts the material, the surrounding area often becomes harder and stronger.

So, choose self-drilling screws if…

1. You’re drilling into harder materials, like metal, and you want a quicker, cleaner finish.
2. You’re working on a large project, and you want to cut down on task time.
3. You’re working with thicker steel or light-gauge metal sheeting.

Choose self-tapping screws if…

1. You’re working with materials or projects that already have pilot holes.
2. You’re fixing into thinner or softer materials.
3. You’re working on a project where the screws will need to be disassembled and reassembled with ease. 

Why quality matters: the Efixings difference

The strength of your build depends on the quality and consistency of the materials you use. 

Cheaping out on screws only leads to snapped heads, stripped threads, and a massive headache when you’ve got to fish another broken screw out of a surface. 

Luckily for you, we have a selection of high-grade screws that can handle high torque and harsh weather conditions. Our self-tapping and self-drilling screws bite into the material with ease and precision and hold well for a long-lasting finish. 

We make it easy to stock up on the exact gauges and lengths you need for professional results every time. Browse our screws and fixings today to find what you need for your next project.