Type AB point has a conical tip and fine spaced threads that are suitable for forming threads in thin metals between 0.015" and 0.050" thick and resin impregnated plywood Steel is often used in applications where strength is the primary consideration, and the black oxide finish offers mild corrosion resistance and lubricity Pan head has a flat top and short vertical sides with a rounded top edge Phillips drive has an x-shaped slot that accepts a Phillips driver and is designed to prevent over-tightening