A trade name turned generic for self-drilling screws, which carry a fluted drill point ahead of the thread so one screw drills, taps and fastens. Point numbers indicate drilling capacity, from #2 for light-gauge sheet up to #5 for steel around half an inch thick, and the unthreaded point must be longer than the material is thick or the thread engages before the hole is finished. They are the standard fastener for metal roofing, siding and steel stud framing.
Use the number three Tek screws on the purlins, the twos keep burning their points before they get through.
Also heard as
- Teks
- self-drilling screw
- self-driller
Do not mix it up with
- Thread-forming screw: A thread-forming screw needs a pilot hole drilled first; a Tek screw drills its own.
Related terms
Thread-forming screw
A screw that displaces material to form its own mating thread in a plain pilot hole, without cutting chips.
Screw
An externally threaded fastener tightened by turning its head, into a tapped hole or a thread it makes itself.
Phillips
A cross-shaped recess drive with tapered walls, the default drive on sheet metal, wood and small machine screws.