Auger drill bits feature a bright, smooth surface for improved chip evacuation and a medium helical structure for stable drilling conditions. Coated solid carbide designs drill three to five times deeper than HSS drills, often eliminating the need for reaming and spot drilling. For best performance and best tool life, it is recommended to use a suitable lubricant/cutting oil or a suitable coolant. Auger drill bits have shorter flutes and a shorter overall length, making them stiffer than machining drill bits, reducing deflection and breakage.The machine drill bit length is 5/8 of the normal processing length of a drill bit. These shorter drill bits are suitable for small lathes and small milling machines where the tool distance is short. Other applications include portable drilling of tough, hard materials. For portable or mechanical drilling in hard steel, stainless steel and other hard materials. HSS models are best suited to drilling steel, cast steel, cast iron or other alloyed or non-alloyed ferrous materials, but they are also suitable for a variety of non-ferrous and non-metallic materials.