You can make holes in a many ways. Yet drilling with a drill bit is most known. Manufacturers offer many types, shapes, materials, sizes of bits. Drilling usually is performed with a power drill which cuts the material by drill bit rotation. Holes in wood, plastic and other soft materials can be made with any bit, but stainless steel, glass, etc require specially designed drilling bits. Some bits are difficult to use with handheld drills and require a drill press. But most of bits can be used with a hand power drills.
Coatings help prevent rust, lessen friction and wear. Zirconium nitride coating adds the strength and improve precision drilling because it decreases friction significantly. Titanium coating is strong, adds corrosion resistance. Titanium also is heat-resistant and has an excellent fatigue limit.
Conical point with a flat surface and linear chisel are used to improve cutting process, removing chips, and reducing thrust. In automated drilling machines are used multi-faceted drill points. They require 50% less thrust, and generate 60% less heat.
Longer bits can drill deeper holes, but they are more flexible, the drill may have an inaccurate location or wander from the intended axis. Common drill bits are available in a few standard lengths: short Screw-Machine-length, the most common medium Jobber-length, and Long-Series. Two or more spiral grooves that run the length of the drill body are called flutes. They help to remove chips from the cutting edge, curl the chip for easier removal, allow the coolant and lubricant to get down to the cutting edge.
One major aspect of drill bit selection is the material makeup of the drill bit itself. Any material work good with the applications for which it is designed. Soft low carbon steel cannot cut hard metals due to their poor tempers, but they can cut wood. High carbon steel hold cutting edge longer, require less sharpening, and can be used with tough steel. High carbon tools also can easily cut woods. High Speed Steel (HSS) is a special type of carbon steel that can withstand high temperatures. High speed drilling causes heating and temperatures can raise dramatically, but high speed steel can undergo it. Tungsten carbide alloys are tough, but brittle and more expensive. Carbide bits are used to drill concrete and tough steel.
Step drill bits are one of the more popular tools for drilling in soft and (or) thin sheet metal. Unibits work fast and make relatively clean holes. Unibits come with as one single drill bit that have progressively sized grooves and ridges. With the tool you need one tool for a variety of jobs instead of many twist drills with various diameters. The one thing that you should avoid using step drill bits on is wood because they are known to split the wood.