Wood screws, concrete screws, and hammer fixings; it can be hard to keep on top of them all. But two screws that stand out for their efficiency and innovative design are the self-tapping and self-drilling screws.
While both screws look a lot alike (and they share similar names), they actually differ in terms of design and benefits. However, both are great tools for home DIYers and builders who are looking to streamline their projects.
Today, ASP will dive into the differences between each one, explain when to use each, and share practical tips so you can work smarter, not harder.
What are self-tapping screws?
Known for their small and trusty design, self-tapping screws have earned their reputation as the small heroes of the construction world.
While you still need to drill a pilot hole, most don’t require you to tap a thread beforehand; splitting and cracking are things of the past. Their sharp, tapered point is designed to pierce a surface with ease while cutting their own thread as they drive into the material for a clean, smooth finish.
The tip of a self-tapping screw can vary depending on the application:
- Thread-forming tips: push the material aside to form the thread, often used for softer materials like plastics or aluminium.
- Thread-cutting tips: cut away material to form the thread, which is better for harder materials or when you want a cleaner finish.
What are self-drilling screws?
Unlike self-tapping screws, self-drilling screws don’t actually require a pilot hole; they can pierce metal and hard surfaces with ease, creating their own hole for a secure and accurate fit.
Designed with a drill bit shaped into the point of the screw, the cutter allows these (often) tiny but robust screws to drill their own pilot hole, cut their threads, and secure the material, all in one go.
Sounds too good to be true? We promise it’s not! In fact, most builders, construction workers, and expert DIYers will have these screws in their toolbox, saving them a considerable amount of time during projects.
Self-drilling screws are often categorised by drill-point numbers, such as:
- #1–#3 tips: ideal for thinner gauge metals and softer materials.
- #4–#5 tips: designed for thicker metals, with #5 capable of penetrating up to around 12 mm (½ inch) of steel.
How do self-tapping and self-drilling screws differ?
So, what exactly makes self-tapping and self-drilling screws so different, apart from one needing a pilot hole and the other not?
1. The tip design
As we mentioned before, self-tapping screws have a sharp point in order to drive through the material, but they’re not as skilful as self-drilling screws (which don’t require a pilot hole).
Self-tapping screws then, come with either thread-forming tips, which displace material to create the thread, or thread-cutting tips, which act more like miniature taps, removing material to form cleaner threads.
These can also come in three different shapes: blunt, pointed, or flat. Thread-cutting screws feature pointed tips, while flat screw are thread-forming, which means they push the material outwards to form a thread profile.
Self-drilling screws tend to be thread-cutting rather than rolling, because the same action that drills the hole also needs to clear space for the threads to bite.
2. Compatible materials
While self-tapping and self-drilling screws can both be used for metal surfaces, self-tapping screws need a pilot hole to be drilled first (otherwise, it isn’t going in).
Due to the nature of self-tapping screws, they’re best used for softer metals, plastics, and wood, which don’t require as much force. They’re especially good for timber since they reduce splitting. Thread-rolling tips are ideal for plastics, as they compress the material rather than cutting it away, producing a firm, lasting fit.
On the other hand, self-drilling screws are designed for hard metals as they pierce the material with precision like no other. Their speed and efficiency make them perfect for attaching sheet metal to steel or aluminium frameworks, roofing and cladding sheets, or securing fixtures to light-gauge steel.
3. Speed vs. control
If you want something that is quick and easy, then self-drilling screws are perfect for you. Since no pilot hole is needed, this is typically the most popular choice for projects where time is of the essence.
However, if you want something more precise and controlled, then self-tapping screws are a better option. The pilot hole dictates the path of the screw, reducing the risk of it wandering or driving at an angle. Self-tapping screws only need to cut threads rather than drill through; driving torque is usually lower, which helps reduce stress on the material.
4. Typical uses
Self-drilling screws are commonly used for metal roofing and cladding to fasten sheets directly to purlins without pre-drilling and securing components in steel framing.
Since they provide such a fast installation, they’re also used for HVAC ducting and projects where builders need to attach metal to timber or plastic without separate drilling
While self-tapping screws are also often used for ducting and timber projects, unlike self-drilling screws, they come in handy for cladding and trimming jobs. It can also be used for junction boxes, pipe clips, or equipment housings.
Quick recap
| Feature | Self-tapping screw | Self-drilling screw |
| Pilot hole needed? | yes | No, the scew drills one itself |
| Speed of installation | Slower than self-drilling, as it requires a pilot hole | Faster than self-tapping, as it’s a two-in-one process |
| Tip style | Sharp or blunt for cutting threads | Drill-bit shaped for drilling and tapping |
| Best for | Thin metals, plastics, timber | Metals, such as steel and aluminium |
Are there any similarities?
It can be a bit confusing to understand at first, but all self-drilling screws are self-tapping, but not all self-tapping screws are self-drilling.
This is because self-drilling screws cut threads into the material as they go, making them a great option when time is of the essence.
Also, both self-drilling and self-tapping screws don’t require a mating component to work! Fewer fixings required, more time and money saved.
Choosing the right type for your project
So to sum up, choosing between self-tapping and self-drilling screws ultimately comes down to the nature of your project, the material, and the balance you need between speed, control, and strength.
When to choose self-tapping screws
- Projects involving timber, plastics, or thinner sheet metals, where pre-drilling holes for greater accuracy is essential.
- When precision is more important than speed, such as in joinery work, cabinetry, or detailed installations where alignment and finish matter.
- Situations where you want to protect delicate materials from splitting or cracking by controlling the diameter of the pilot hole.
When to choose self-drilling screws
- Structural and large-scale tasks that require hundreds of fixings, such as roofing, decking, subframes, or attaching steel to steel.
- For builders and contractors who need maximum efficiency, cutting out the pilot-hole stage without sacrificing holding strength.
- Heavier-duty applications involving steel or composite materials, where the drill-point design saves both time and tool wear.
Tip: If you’re unsure between self-tapping and self-drilling, start with self-drilling on metal-heavy or mixed connections for a quicker installation.
The right screws for your project are this way!
At ASP Ltd, we want to make sure you complete your project the right way: no cutting corners, no incompatible fixings.
Our bulk self-drilling screws are engineered to provide the holding strength and ease of use required on-site, as they drill, tap, and fasten in one go.