The WD1 coating on these drill bits is harder than TiAlN and EgiAs coatings, has excellent heat resistance, and protects the tool from wear when drilling into steel, stainless steel, hardened steel, and cast iron. Fast-spiral drill bits evacuate chips more quickly than standard spiral-flute drill bits as the bits drill into a workpiece.,High-speed steel screw-machine length drill bits provide more flexibility and absorb more shock and vibration than cobalt, powdered-metal, and carbide screw-machine length drill bits, making them suitable for use in manual drilling machines and handheld power tools. They may leave a rough finish on the hole. Screw-machine length drill bits are shorter than jobber length and maintenance length drill bits of the same size. Also called stub length drill bits, they provide more strength and rigidity and can drill straighter holes than longer drill bits. Their short length also allows them to access tight spaces where longer drill bits cannot fit.