These ForgeFix Phillips Baypole Screws with wafer head are specifically designed for joining PVCu sections particularly in bay windows The nails have a self-drill tip and are zinc plated for increased corrosion resistance and durability The wafer head distributes the load under the screw head offering a firm positive fixing in a similar way to that of a washer APPLICATION The large wafer head distributes the load on numerous types of PVCu sections requiring joining Zinc coatings prevent oxidation of the protected metal to create a longer lasting finish It does this by forming a barrier and by acting as a sacrificial anode if this barrier is damaged Zinc oxide is a fine white dust that in contrast to iron oxide does not trigger a breakdown of the substrate’s surface integrity as it is formed The zinc oxide if left intact can act as a barrier to further oxidation in a way similar to the protection afforded to aluminium and stainless steels by their oxide layers The Phillips screw has four simple tapered slots It is designed so that a Phillips tip screwdriver can turn a Phillips screw with increasing torque When the torque gets too strong for the tip the screwdriver tip winds itself out of the screw thus preventing over-tightening and or damage to the screw head A self-drilling screw is similar to a sheet metal screw but it has a drill-shaped point to cut through the substrate to eliminate the need for drilling a pilot hole Designed for use in soft steel or other metals