What are self-drilling screw tips?

Chris

4th March 2020

A self-drilling tip effectively drills its own pilot hole through the material as the screw is being driven in.

It has a cutting blade which sends the waste material back up the body of the screw and out of the hole.

Self-drilling tip with wings

Some self-drilling tips have wings above the drill tip. These wings drill a clearance hole for the screw as it’s being driven in.

A screw with this type of tip is suitable for use in thicker materials, and is designed specifically for use when joining wood to metal.

As the screw is being driven in, the wings enlarge the hole in the material created by the drill tip.

The threaded part of the screw can now pass through the hole without the timber ‘jacking’ (pulling away from the metal).

When the wings come into contact with the metal, they break off, allowing the threads to fully engage with the metal.

Advantages		Disadvantages
No need for a pre-drilled hole of any kind. As a result, you don’t need to worry about drilling the correct size pilot hole – the drill bit does that for you! Manufacturers claim that self-drilling screws increase productivity as they reduce the number of steps needed to join materials together They also claim that self-drilling tips allow the material to be clamped together more tightly. Usually have a higher heat tolerance compared with non-self-drilling screws. This means that they can join metal to metal at higher speeds Tend to be stronger than those without self-drilling tips. This is because the tip and sometimes even the whole screw is made out of drill steel. Available for use in various materials including wood, metal and plastic		May be more expensive to purchase and less widely available As they are a relatively new technology, not all of the disadvantages are known yet