Self drilling screws are perfect when used on hard uPVC installations and metal. Grest for window hinges, door hinges, door locks, window locks etc.
Self drilling screws are designed to mimic the tip of a drillbit. This allows it to bore in to hard substances with minimum effort. This saves time and energy as you dont have to drill a pilt hole to guide in the screw, the self drilling screw does it all in one motion.
Use the self drilling screw for harder materials such as metal and hard plastics. Great for drilling two types of different material together.