The Tek Screw (Self-Drilling Screw): the “no pre-drill” fastener

If you’ve ever watched someone run a screw straight through sheet metal like it’s nothing… odds are it was a Tek screw.

A Tek screw is a self-drilling screw — the tip is shaped like a tiny drill bit, so it drills a pilot hole and drives itself in one motion. Super common in metal roofing, metal studs, HVAC, steel buildings, carports… basically anywhere “metal meets metal” (or metal meets wood) and you want speed.

Quick nerd note (that actually matters): “Tek” is also a brand name that became the generic term people use for self-drillers.

Where Tek screws are money

You’ll see them used for:

• Metal to metal (sheet to studs, purlins, angle, brackets)

• Metal to wood (roof panels to wood framing)

• Light gauge framing (stud/track)

• Any job where pre-drilling is just wasted motion

The most common screw-up

Using the wrong Tek point for the thickness you’re drilling.

Tek points are often labeled Tek 1 / 2 / 3 / 4 / 5 (sometimes “point #2,” etc.). In plain English:

• Lower number = lighter drilling

• Higher number = thicker steel capacity

If you try a too-small point on thicker steel, you get the classic:

• squeal + heat

• a tip that burns up

• stripped heads

• and a screw that just polishes the metal instead of drilling it 😅

Heads you’ll run into (and why it matters)

This changes how it seats and what tool you’re grabbing:

• Hex washer head: roofing + general metal work (fast, strong, forgiving)

• Pan head: lighter assemblies, a bit “cleaner”

• Flat head: when you need it flush (less common for roofing)

The washer thing (EPDM / bonded washer)

A lot of roofing self-drillers come with a bonded sealing washer (metal + EPDM rubber). That washer is there to seal water and spread load so you don’t crush/dimple panels.

Over-tighten it and you can damage the washer and create leaks; under-tighten and it won’t seal. The goal is snug and evenly compressed, not squished to death.

Quick “buy the right one” cheat sheet

If you’re standing at the shelf:

Metal roofing to wood

• Hex washer head + bonded EPDM washer

• Exterior-rated coating

• Tek point depends on what you’re drilling through (panel only vs panel + light steel)

Metal studs / track

• Tek point matched to stud thickness

• Pan head or hex (preference + spec)

Metal to thicker steel

• Move up Tek point rating (don’t brute force it)

Pro install tips (simple, but saves time)

• Steady pressure — don’t “peck” at it

• If it doesn’t bite quickly, you’re probably under-pointed

• Let it drill, then drive

• Worn bit = cam-out city (and you’ll blame the screw unfairly)

References

1. ITW Buildex (TEKS) — product catalog / selector guide (drill point types + applications)

2. ITW Buildex — “TEKS Self-Drilling Fasteners” product data (specs + drill points)

3. McElroy Metal — roofing screws + bonded washer basics

4. WV Metal — why over-tightening roofing screws can cause leaks