There are many ways to drill a hole in something. But the most common is drilling. Manufacturers offer many types, shapes, materials, sizes of drill bits. In order to create holes bits are usually attached to a powered drill to cut through the material by rotation. You can drill soft materials with most any bit, but brittle materials require specially designed tools. Forstener bits, large diameter core bits and other should be used with a drill press. But most of tools can be used with a hand power drills.
The general purpose drill points are usually 118°. They are typically used for cutting into soft metals such as aluminum, whereas the 135° variant is best suited for hardened materials, such as stainless steel. 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.
Step drill bits are one of the more popular tools for drilling in soft and (or) thin sheet metal. They work at a faster speed to make relatively clean holes. Unibits come with as one single drill bit that have progressively sized grooves and ridges. So you just need one tool for a variety of jobs. But you should avoid drill wood with unibit because the bits split the wood and the hole will be low-quality.
One major aspect of drill bit selection is the material makeup of the drill bit itself. Not all bits will work on all applications. 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. HSS is a type of carbon steel with more complex alloys and it can withstand higher 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.
Coatings help prevent rust, lessen friction and wear. ZiN – Zirconium nitride film adds the strength, decreases friction and improve heat removal. TiN (titanium) coating is adds corrosion resistance and helps to remove heat from the cutting edge. Titanium also is heat-resistant and has an excellent fatigue limit.