A self-drilling screw is a screw that has a drill point at the end of the tip.
Its curved end tips, shaped like a drill, allow it to work as a fastener without the need to drill a pilot hole in the mounting surface.
It’s a screw that drills its own holes and fastens materials such as metal, wood, as well as other low-density materials.
This type of screw is also called Teks (or Tek) screw, after the manufacturer that originally made self-drilling screws famous.
Safe to say, they’re an essential element in everything from construction to carpentry.
But here’s the catch:
You can find self-drilling screws in different sizes, lengths, and thicknesses.
So, choosing the wrong size can ruin your project to the point of no recovery.
This comprehensive self-drilling screw size chart will help you select the right tools to make your project a success.
Overview of a Self-Drilling Screw Chart
Self-drilling screws are used in various fastening and fixing applications.
If you’re new to the world of self-drilling screws, finding one with the right size, thickness, and length can feel challenging.
To make things easier for you, here are some important self-drilling screw specifications you should consider.
#1. Material
Metal
Self-drilling screws are designed with special heads that enable them to fasten metal to metal.
They have exceptional holding strength and can drive through thicknesses of up to 0.125 inches at a speed of 1500 RPM.
These screws are highly useful across a wide range of applications, including metal roofing, framing, HVAC, automobile construction, and furniture manufacturing.
Keep in mind that while metal screws can be used for other materials, the reverse is not possible, as only metal can cut through metal.
Wood
Self-drilling screws can also be used for tasks involving wood, such as for constructing, repairing, and maintaining decks, sheds, and outbuildings, among other woodworking scenarios.
Although wood screws are still the best choice for projects with wood, limit using self-drilling screws for metal-to-wood fastening.
You can find out more on our wood screw sizing chart.
#2. Uses of Self-Drilling Screws
Self-drilling screws are a category — not a specification.
So, you’ll find different types of self-drilling screws.
Each of these types has its distinct advantages for connecting materials to ensure enhanced productivity and performance.
Take a look at some of the main self-drilling screw types.
Concrete Self-Drilling Screws
Concrete self-drilling screws penetrate heavy-duty materials like concrete, block, and brick, although you might need to create a pilot hole for easy installation.
They come in different lengths and also vary in head styles.
For example, if you intend to use self-drilling screws for masonry applications, flat-head and hex-head self-drilling screws will be your best choices.
Flat head screws are best used in applications where the screw needs to be countersunk in the type of concrete (block or otherwise) being fastened.
On the other hand, hex head screws are easier to install, but they have raised caps because of which they don’t flush to the surface to provide a smooth, camouflage-like finish.
Countersunk Self-Drilling Screws
Countersunk self-drilling screws flush to the target surface to provide a seamless finish.
They come in different lengths, diameter sizes, head diameters, and head heights to give you more options to choose from for different project applications.
You can also find them with or without wings to secure timber and steel substrates.
They come in numbers 1 to 5, with 5 being the best at penetrating materials.
These screws are suitable for numerous applications, from pre-drilled hinges to brackets, and are flexible enough to attach metal studs and fixings into steel without tearing or damaging the material.
Low-Profile Head Self-Drilling Screws
Low-profile self-drilling screws are designed to attach framing to any metal of up to 3/16” thickness.
They come in different subtypes, such as pancake-head Tek screws, wafer-head screws, and baypole self-drilling screws.
They are suitable for applications requiring unobtrusive fixing.
Self-Drilling Screws with Wings
Some self-drilling screws come with “wings” intended to help enlarge the hole in the material being fastened.
The wings bore through the material to ensure it doesn’t climb up the shank, which helps provide an easy path for the threaded portion of the screw.
This is especially helpful when drilling into thick materials like concrete, wood, and metal.
#3. Types of Self-Drilling Screws
You can find any kind of self-drilling screw at HomeDepot.com
Self-drilling screws are classified based on variations in both the head and body.
There is a self-drilling screw for every type of application; you’ll find the common ones listed below.
Binding Head Screw
This type of self-drilling screw head has a thicker bearing surface and a deeper drive slot.
It is commonly used to make electrical connections, as its pan-like wide head offers high strength and precision for holding terminals and wires.
Bugle Head Screws
This type of screw has a countersunk head with a flat top, much like a flat screw, and features an under-head bearing surface.
It enables better distribution of bearing stress over a wider area compared to a standard flat-head screw.
It drives flush with the surface and is often used to fasten soft materials like drywall, OSB, plywood, and wood.
Button Head Screw
This type of screw has a head that resembles a dome. It provides a good clamping force, making it suitable for connecting thin metal.
It may also come with a hex drive to eliminate the risk of slipping and stripping.
Cement Board Screws
This type of screw has a countersunk head and a unique rib design that connects flush at any angle to provide a smooth surface.
It is used to attach cement boards, dense wood, as well as light gauge steel.
Eye Lag Screws / Eye Hole Screws
This type of screw is bigger than standard screws and requires a special driver bit for installation.
It has a lag screw threading on one end and a closed loop on another for fastening cables, ropes, and wires to drop ceilings.
You can check out our eye bolt size chart here to learn more.
Flat Head Self-Drilling Screws
This type of screw comes with a flat top that lands flush with the surface of the material.
Because it does not have a protruding head, you can cover it with a screw covering to achieve a smoother and more aesthetic appearance.
Hex Head Screws
This type of screw fits easily into a hand drill’s socket head to ensure a more efficient drilling procedure.
It comes in various sizes and materials, which respond to a range of applications.
- Flange head, which allows for more clamping load/force.
- Washer heads which are prized for their efficiency and ease of use. It comes in sizes from 1/4 to 14×1.
Oval Head Screws
This type of screw offers a 90-degree countersunk angle similar to flat-head screws, although the top of its head protrudes above the surface.
They are often used in aesthetic applications like switch coverings to present a clean, finished look.
Pan Head Screws
This type of screw has a slightly flat rounded head with a moderate height and diameter.
They are flat load-bearing screws and have high outer edges, providing a tighter torque and fastening with high precision.
Truss Head Screws
This type of screw has an extra wide head to distribute pressure equally.
It has a smooth finish and is typically made from stainless steel, which makes it corrosion-resistant and self-draining, thus preventing bacterial growth.
It is commonly used in the food, pharmaceutical, and sanitary industries.
#4. Thread Selection
Length
Choose a fastener with sufficient threads, as threads provide the clamping force necessary for engaging the base material being fastened.
For example, if you’re attaching the screw to attachments with 1/4” thickness, your self-drilling screw should also have the same diameter of threads, at the least. Otherwise, it will not engage fully with the base metal.
Pitch
To determine the appropriate type of thread pitch, look at the diameter of the screw and the thickness of the material you’ll be using for the fastening.
Remember, the thicker the material, the greater the number of threads.
They’ll allow the tap to cut into the base material with less torque for a seamless experience.
Using a Self-Drilling Screw Size Chart
First, examine parameters such as the type of materials you’ll connect with it.
Let’s start with the thickness and the type of material you’ll be using it on.
Narrowing this down is an important part of the selection process, as some self-drilling screw types are designed for specific materials and purposes.
You’ll also need to consider the Tek screws dimensions and types of points used, which include the flute, length, and point wings, for efficient application.
Next, consider their drill load. Being familiar with the amount of force they place on the drill during installation can help you make more informed decisions.
Something to Remember:
Many people believe that self-tapping screw sizes and self-drilling screw sizes are interchangeable, but that’s not the case, as this article will demonstrate.
Self-Drilling Screw Charts
Standard Self-Drilling Screw Sizes
| Nominal Size | Major Thread Diameter |
|
#6 |
0.138 |
|
#8 |
0.164 |
|
#10 |
0.19 |
|
#12 |
0.216 |
|
1/4 |
0.246 |
The self-drilling screw size indicates the thickness of a nail.
The higher the number, the thicker the screw.
You will need to choose the appropriate diameter or thickness of your self-drilling screw, as it determines the efficiency of your application.
For example, a #12 self-drilling screw will work for fitting unsupported roofing sheets of light to heavy gauges, while a #6 self-drilling screw can only be used to fasten metal to metal.
Self-Drilling Screw Size Applications
To figure out the correct point, you will first need to familiarize yourself with the thickness of the material you want to fasten.
| Gauge | Minimum Thickness | Maximum Thickness |
|
26 |
0.0163 |
0.0172 |
|
25 |
0.0179 |
0.0188 |
|
22 |
0.0269 |
0.0283 |
|
20 |
0.0329 |
0.0346 |
|
18 |
0.0428 |
0.0451 |
|
16 |
0.0538 |
0.0566 |
|
14 |
0.0677 |
0.0713 |
|
12 |
0.0966 |
0.1017 |
|
10 |
0.118 |
0.124 |
Once you’re familiar with both these charts, take a look at the length of the fastener’s drill bit, as that is used to create a hole and fasten materials together.
To put it simply, it determines the screw’s drilling capacity.
| Screw Size |
Point Type |
Material Thickness (Approx) |
|
10 |
1 | 0.95 |
|
12 |
||
|
1/4 |
||
|
6 |
2 |
0.1 |
|
8 |
0.1 |
|
|
10 |
0.11 |
|
|
12 |
0.21 |
|
|
10 |
3 |
0.175 |
|
12 |
0.21 |
|
|
14 |
0.22 |
|
|
1/4 |
0.21 |
|
|
5/16 |
0.21 |
|
|
12 |
4 |
0.22 |
|
14 |
0.25 |
|
|
1/4 |
0.312 |
|
|
12 |
4.5 |
0.375 |
|
12 |
5 |
0.5 |
|
1/4 |
If you’re drilling lightweight materials, a self-drilling screw with a #1 or #2 point will suffice.
However, if you’re drilling thick, heavy-duty materials, stick with a #5 point. It can cut through 1/2” of steel without requiring a pilot hole.
Also, pay attention to the kind of screw gun you’re using.
For example, you should use a 2,500 RPM screw gun for points #1 to #3 and a 1,000 RPM screw gun with high torque for points #4 and #5.
This will ensure a seamless application, which can prevent burning up the screws or the motor in the screw gun.
You may also want to check this video out to prevent mistakes during installation.
Frequently Asked Questions
#1. What sizes do self-drilling screws come in?
Self-drilling or Teks screws sizes come in whole numbers and fractional inches. They range from #6 to #14 and 1/4”.
#2. What thickness of metal can self-drilling screws penetrate through?
Self-drilling screws have drill points numbered #1 to #5, with #5 being the best choice for heavy-duty equipment. It can drill through and fasten up to 1/2” of steel.
#3. Do self-drilling screws come loose?
Yes. Self-drilling screws can come loose during assembly and can also pull out under tension.
In Summary
Looking to save time and money? Try self-drilling screws.
They ensure a secure attachment and efficient, rapid installation without a pilot hole.
They’re effective, but their performance as a fastener depends on the proper selection of the screws.
Refer to this self-drilling screw size chart to help you make the right choices for your projects.