What Is a Self Tapping Screw? Everything You Need to Know
If you’ve ever driven a screw straight into metal or plastic and thought, “That went in a bit too easily…” - chances are you were using a self tapping screw.
These clever little fasteners don’t just sit there and hold things together. They do a bit of the heavy lifting themselves.
Self Tapping Screws – What Are They and How Do They Work?
A self tapping screw is a type of screw that creates its own thread as it’s driven into a material. In simple terms, it taps its own hole as you install it.
Because of this, self tapping screws are among the most widely used fasteners across industries. You’ll often hear them called sheet metal screws, especially when used with softer metals.
They’re incredibly versatile and can be used with:
They also come in a variety of head and drive types, including:
- Pozidriv recess
- Slotted drive
- Torx recess
- Hex head
- Security self tapping screws
- Micro self tapping screws
- Hammer drive screws
How Do Self Tapping Screws Work?
Self tapping screws feature sharp, hardened threads designed to cut or form a thread as they’re driven in.
Here’s what typically happens:
- A pilot hole is often drilled first
- The screw is inserted
- As it turns, it cuts or forms threads into the material
The pilot hole should be no larger than the screw’s root diameter (the inner core of the screw).
Some self tapping screws have pointed tips, meaning they can sometimes skip the pilot hole entirely.
You can install them using:
- Screwdrivers (manual or electric)
- Wrenches
- Torx or Allen keys
- Security tools (depending on the head type)
Thread Cutting vs Thread Forming Screws
Not all self tapping screws behave the same. They fall into two main categories:
Thread Forming Screws
- Push material aside rather than removing it
- Ideal for plastic
- Usually require a pilot hole
- Important: Avoid overtightening, as this can crack the material
Thread Cutting Screws
- Cut and remove material as they go in
- Best for wood and metal
- May not require a pilot hole (though it helps with accuracy and ease)
What Are Self Tapping Screws Used For?
Their main job is simple:
👉 Joining two materials when you only have access from one side
They’re also perfect for applications where parts may need to be removed and reinstalled, such as:
- Furniture assembly
- Air conditioning units
- Maintenance panels
Because they create their own threads, they can often be reused in the same hole.
Self Tapping Screw FAQs
What’s the difference between a self tapping screw and a normal screw?
A standard screw has a uniform thread and typically needs a pre-threaded hole.
A self tapping screw has cutting edges, allowing it to create its own thread.
Can you reuse a self tapping screw?
Yes, but proceed carefully. There’s a chance the thread may strip during removal.
If that happens, simply use a slightly larger screw.
What size pilot hole should I use?
The pilot hole should be no bigger than the screw’s root diameter.
How much weight can a self tapping screw hold?
On average: 35–45kg
However, this depends on:
- Screw type and size
- Material
- Installation method
- Load direction and angle
Will they go through stainless steel?
Not on their own. You’ll need to drill a pilot hole first.
If you want a screw that drills and taps in one go, look for self-drilling screws.
Can self tapping screws be used with wood?
Yes. Use corrosion-resistant screws, as wood retains moisture and can cause rust.
Can you use them in concrete?
Yes, but only specific masonry self tapping screws.
Steps:
- Drill a hole
- Clean out dust
- Slowly insert the screw
Using wall plugs is recommended for better grip and to prevent crumbling.
How are self tapping screws measured?
Two key measurements:
Diameter
- Measured across the outer threads (major diameter)
- Minor diameter measures the inner core
Length
- Varies by head type:
- Pan/round/hex: bottom of head to tip
- Countersunk: top of head to tip
- Oval: widest point of head to tip
Final Thoughts
Self tapping screws are a bit like the multitool of the fastening world. They drill, thread, and fasten all in one smooth move.
Less prep, fewer tools, and a reliable hold make them a go-to choice for everything from DIY projects to industrial applications.
Looking for Self Tapping Screws?
We stock a wide range of self tapping screws in various sizes, materials, and head types to suit your project.
Browse our collection and find the perfect fit for your next job.
