There are many ways to drill a hole in something. Yet drilling with a drill bit is most known. Drilling bit comes in many sizes, shapes , etc. Drilling usually is performed with a powered drill which cuts the material by drill bit rotation. Holes in wood, plastic and other mild materials can be made with any tool, but stainless steel, glass, and so on require specially designed drilling bits. Forstener bits, large diameter core bits and so on should be used with a drill press. But most of tools can be used with a hand power drills.
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.
Most of the drill bits have 118° drill points. They work well for cutting into copper, aluminum, and mild steel, whereas the 135° drill point is good for stainless steel, hardened steel and another tough materials. A 135° drill is flatter than 118°, which means that more of its cutting lips engage with the material surface sooner to begin the full metal cutting action.
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. Flutes are two or more spiral grooves that run the length of the drill body. 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.
The material of the drill bit is important aspect of the tool selection. Any material work good with the applications for which it is designed. Low carbon steel is soft and dulls quick when drilling hard metals, but they cut wood great. High carbon steels require less sharpening, and hold their effectiveness longer. High carbon tools also can easily cut woods. HSS is a type of carbon steel with more complex alloys and it can withstand higher temperatures. Friction created by high speed turning can raise temperatures dramatically, but HSS can undergo these types of drillings. Tungsten carbide bits are more expensive, tough and brittle. Carbide bits are used to drill concrete and tough steel.
Any master working with a sheet metal, boxes or thin mild metal has a Step drill bit (Unibit). Unibits work fast and make relatively clean holes. Step drills come with just one single drill bit with progressively sized grooves and ridges. So you just need one tool for a variety of jobs. The one thing that you should avoid using step drill bits on is wood because they are known to split the wood.