Self Drilling Screws

As the name suggests self-drilling screws, are designed to bore into a surface without the need for a pre-drilled pilot hole. Cromwell stock a wide range of self-drilling screws from big name brands like Qualfast so you can be assured of quality at an affordable price.

What are self-drilling screws?

Self drilling screws feature a tip shaped like a drill bit designed to bore into a workpiece without the need for predrilling a pilot hole, adding to job efficiency. Often referred to as Tek screws due to the brand that originated the design, they are mostly made from stainless steel and come in a range of sizes and types to suit the needs of a specific application.

Why self-drilling screws?

Speed and efficiency is the main reason for the use of self-drilling screws, as they don't require a pilot hole. They are hardy enough to cut through a variety of materials to perform fastening applications, including metal, wood and even plastic.

Types of self-drilling screws

Countersunk - As with standard countersunk screws these are designed to bore deep enough for the surface to sit flush with the head of the screw, creating a smooth finish.

Low-profile - Used when an unobtrusive fixing is required, they come in various different styles dependent on the application.

Winged - Designed to drill into tougher materials like metal, the winged design helps to enlarge the hole making the thread pass through easier.

Considerations when choosing self-drilling screws

Size - As with standard screws the length, thickness and overall size of the screw should be considered to be in keeping with the desired application.

Application - Will you require a countersunk finish or are you drilling into metal? Selecting the screw suitable to the desired finish will save time and effort in the long run.

Flute length - This is the size of the drilling tip of the screw, if you are cutting into a thick workpiece, then you will need to ensure that the flutes are sufficient to bore deep enough into the material before the thread engages, otherwise this could damage the screw. Similarly, if the flute becomes blocked the cutting action will stop.

FAQ

Is there a difference between self-drilling and self-tapping screws?

Yes. Although often confused, self-tapping screws are designed for thin sheet metal, and although they cut their own thread, they often need a pre-drilled hole. Self-drilling screws do not require a predrilled hole.

How tight should a self-drilling screw be?

Screws should be tightened securely or to the required torque levels of the application it the case of screws like pan-head screws.