Cutting Holes in Solid Materials

There are many ways to drill a hole in something. But the most common is drilling. Drilling bit comes in many sizes, materials, etc. In order to make holes drilling bits are usually attached to a powered drill to cut through the workpiece by rotation. Holes in wood, plastic and other soft materials can be made with any tool, but stainless steel, glass, and so on require specially designed drilling bits. Some drilling bits are dangerous to use with handheld drills and require a drill press. But most of bits can be used with a hand power drills.

Grinding a conical point with a flat surface to create a linear chisel helps to reduce the thrust and improve the process of cutting and removing the chips. In automated drilling machines are used multi-faceted drill points. They require 50% less thrust, and generate 60% less heat.

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° bit is flatter, therefore more of its cutting lips start to perform the full metal cutting action.

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. Low carbon steel is soft and dulls quick when drilling hard metals, but they cut wood great. High carbon steel hold cutting edge longer, require less sharpening, and can be used with tough steel (see also best cordless drill). They can cut both woods and metals. 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 bits are more expensive, tough and brittle. This material is used to drill hardened and stainless steel.

Drill bit coatings are intended to lessen friction, wear, and prevent rust. 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 has a high heat limit and an excellent fatigue limit, similar to steel, but somewhat less on both counts.

Any master working with a sheet metal, boxes or thin mild metal has a Step drill bit (Unibit). They work at a faster speed to 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.