What are Self-Drilling Screws? and Other FAQ
Self-drilling screws are a type of fastener that combines a drill bit and a tapping screw into a single component. That means they can drill their own hole and cut threads in one step, making them one of the most efficient fasteners available, especially for metal-to-metal connections.
Instead of needing a separate pilot hole like traditional screws, self-drilling screws save time and reduce tool changes on the jobsite. You can identify them easily by their distinctive drill bit-style tip.
In this article, we consulted our experts to put together as much info as we could to answer all of the self-drilling screws questions.
What Are Self-Drilling Screws Used For?
Self-drilling screws are commonly used in:
- Metal building construction (steel framing, metal panels)
- Roofing and siding installation
- HVAC applications
- Electrical enclosures
- General fabrication in sheet metal, aluminum, and thin-gauge steel
They’re ideal where speed matters and materials are dense enough to require a bit, but soft enough to avoid stripping or over-driving.
How Are They Different Than Other Screws?
Here's how self-drilling screws stand apart:
| Screw Type | Requires Pilot Hole? | Taps Threads? | Drills Own Hole? |
|---|---|---|---|
| Wood Screw | No | No | No |
| Self-Tapping Screw | Yes | Yes | No |
| Self-Drilling Screw | No | Yes | Yes |
Self-drilling screws combine drilling and tapping. Self-tapping screws require a pre-drilled hole. Wood screws grip into soft material but don’t cut threads or bore holes.
For more info on the difference between self-drilling and self-tapping, see our blog post here.
When Should I Use Self-Drilling Screws?
These screws are built for metal substrates, whether it’s sheet metal, steel studs, red iron, or square tubing. Our expert, Matt B. notes to use self-drilling screws when:
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You don’t want to pre-drill.
- Self-drillers save time by creating their own hole as they drive in. Perfect for getting work done faster, especially on ladders, lifts, or tight spots.
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You need a clean, precise install.
- The drill point ensures accurate placement without wobbling or walking across the material.
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You’re fastening wood to metal.
- That’s where winged self-drilling screws come in. They chew through the wood first, then snap off at the metal for a smooth finish.
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You’re attaching panels, trailers, or sheathing.
- Whether you’re decking out a van trailer, framing out steel studs, or installing corrugated roofing, there’s a self-driller for the job.
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You need structural strength.
- Some self-drillers are rated to go through ½” structural steel. That’s serious holding power without needing a drill press.
They're a go-to for metal-to-metal fastening, particularly in light-to-medium gauge materials. They're also used in wood-to-metal scenarios where speed and thread engagement are crucial.
What Are the Disadvantages of Self-Drilling Screws?
While self-drilling screws are incredibly convenient, there are a few things to keep in mind:
- Not ideal for very hard or thick metals, they can burn out or stall
- Easier to overdrive, especially if not using a drill with adjustable torque
- Can cause material splitting if misused in thin or brittle substrates
- The drill tip can wear out faster than a standard bit or tap over repeated use
If you're driving into extremely hard material, consider pre-drilling or using a more specialized anchor.
Will Self-Drilling Screws Go Through Metal?
Yes, that’s what they’re made for. Self-drilling screws will penetrate thin to moderate thickness steel without pre-drilling.
For thicker materials or structural steel, look for longer drill tips or hardened screws designed for heavy-duty metal connections.
Our expert, Matt, notes:
A heavy gauge self-drilling screw has a really long drill point and the threads are much tighter. That tells you it's for heavy gauge product, like red iron or half-inch thick material, structural steel. Those screws will actually go through that half-inch thick material without having to drill a hole.
Meanwhile, a common issue people have with the wrong screws:
Light-gauge screws won’t cut it in heavy steel. If you’re drilling into thick metal and your screw keeps burning out or snapping, it’s the wrong screw. Always match the screw type to metal thickness.
For reference, the distinction between light and heavy gauge metal isn't universal, but typically 16 gauge and up is considered light gauge, while 12 gauge and down would be considered heavy.
Types of Self-Drilling Screws
Let’s break them down by key categories so you can choose the right one for your project.
Self-Drilling Screws by Head Type
Different head styles serve different fastening applications and tool types:
- Hex Washer Head – Common in metal roofing and framing. Easy to grip with a socket or nut driver.
- Flat Head – Sits flush with the surface. Used in applications where appearance matters.
- Pan Head – Low-profile with wide bearing surface. Great for electrical and light-duty use.
- Truss Head – Large surface area with a low profile. Often used with soft or thin materials.
Self-Drilling Screws by Material or Coating
The material and coating determine corrosion resistance and durability:
- Zinc-Plated Steel – Affordable and corrosion-resistant for indoor applications.
- Galvanized Steel – Better for outdoor use and exposed environments.
- Stainless Steel – Top-tier corrosion resistance. Best for coastal, marine, or animal confinement areas.
- Painted Head Screws – Color-matched for roofing and siding projects.
Self-Drilling Screws by Tip, Thread, and Other Characteristics
These determine performance and compatibility:
- Tek Screws – A brand name commonly used to describe self-drilling screws. Tek points are numbered (#1 through #5), with higher numbers handling thicker metals.
- Fine Thread – Ideal for metal-to-metal fastening.
- Coarse Thread – Better for metal-to-wood or soft material fastening.
- Winged Screws – Have small "wings" to widen holes in softer materials, then break off when hitting metal.
- Sealing Washer – Used in roofing or exterior panels to create a watertight seal.
Final Thoughts
Self-drilling screws are all about efficiency. They eliminate the need for pre-drilling, save labor time, and reduce error, making them a favorite across construction trades. Just be sure to choose the right head type, coating, and tip strength for your job, and you’ll get strong, long-lasting connections every time.
