Drill bit sets include a collection of drill bits, typically featuring a range of sizes to ensure suitability for different applications. Drill bits are the tools which allow drills to cut holes into different materials through the application of circular torque, or rotational force. The upper part of a drill bit is called the shank and this is attached to the chuck, a special clamp within the main body of the drill.
Most modern drill bits are made from various types of steel. Some of the most common types include:
- Carbon Steel – this is the ideal choice if you need a tough drill bit able to cut into harder substances. Carbon steel is resistant to high temperatures and bits made from this material typically have longer lifespans than alternative options
- High-Speed Steel (HSS) – this material remains firm when subjected to high temperatures and can cut quickly and accurately
- Cobalt Steel – the cobalt admixture increases strength and resistance to both heat and friction
- Tool Steel with Tungsten Carbide Tips (TCT) - these have a tough and stable tip with a longer working life
In addition to the use of alloys, modern drill bits often include chemical coatings to enhance their performance. Common coatings include:
- Black Oxide – this prevents corrosion and increases resistance to stress. It also helps to retain any lubricants which have been applied, making it a good choice for iron and steel drilling
- Bronze Oxide – this coating is also an effective choice for additional stress resistance. It is often used to help identify cobalt steel and can be used in combination with black oxide to help identify high-speed steel bits
- Titanium Nitrate – added to increase the rigour of drill bits, this coating also helps to protect against the high temperatures generated by frictive materials like iron, steel and aluminium, thereby increasing their lifespan
- Ferrous Oxide - another coating which provides effective shielding against heat
Drill bit sets are useful because they contain a selection of drill bits in different shapes and sizes. Some contain bits specifically designed for use with certain substances - for example, masonry,wood, metal, plastic, concrete etc - while others are intended to meet the needs of professionals who routinely work with multiple materials.
Drill bit sets made specifically for hobbyists and DIY enthusiasts are also available. These tend to feature smaller bits intended for lighter work. Drill bit sets are normally supplied in sturdy carry cases, with individual components on clear display for ease of use.