Self Drilling Screws – Modify Truss Phillips (TPZ) Zinc Plated #6 x 1" (3.5x25mm) (900 PCS) are designed for fast, accurate fastening in thin to medium metal applications without requiring pre-drilling. Made from case-hardened carbon steel and coated with zinc plating, these screws provide strong durability along with corrosion resistance for everyday construction and industrial use. The hardened drill-point tip allows them to cut through metal and create threads in a single step, eliminating separate drilling operations.