Drills are hand-held tools with rotating drill bits used to fabricate holes in multiple materials. They are widely used in construction, carpentry, metalworking, assembly, and maintenance.

Most drills used today are powered, and use a chuck to grip the bits of the drills. The drill bit is gripped by a chuck at one end of the drill and rotated while pressed against the target material. The tip of the drill bit does the work of cutting into the target material, either slicing off thin shavings, grinding off small particles, or crushing and removing pieces of a workpiece.

Drills utilize the ability of a harder material in the drill bit, under rotational and linear force, to deform or displace a softer material. An example includes a steel drill-bit having the capability to drill into softer materials, such as wood or soft plastics like PTFE (Teflon) or Polyoxymethlene (Delrin).

Drills can be powered manually, using electricity, with compressed air, or with the help of an internal combustion engine. Drills with a percussive action are typically used in hard materials, such as masonry units or rocks. Drilling rigs are used to bore holes in the earth to obtain oil or water. Oil wells, water wells, or holes for geothermal heating are created with large drill rigs up to a hundred feet high. Certain types of hand-held drills are also used to drive screws.

Types of Hand Drills

One of the main classification's of drills is hand drills, which include bow drills, pin chuck drills, jeweller's drills, as well as:

• Brace and bit drills are manually powered drills with U-shaped crankshafts that rotate for drilling to occur.
• Gimlets are used to drill small holes in wood and have hollow cross handles at one end.
• Breast drills are more commonly referred to as the "eggbeater drills," and are designed with plates for the chest to apply pressure and circular crankshafts for the drilling.
• Push drills are similar in shape to a hand screw driver but are used to drill small holes in wood.
• Pistol-grip drills are very common type in use today, and are available in a huge variety of subtypes.
• Right-angle drills are a less common type used by tradesmen such as plumbers and electricians.
• Hammer drills are similar to a standard electric drill, with the exception that it is provides a hammer action for drilling masonry.
• Rotary hammer drills combine a primary dedicated hammer mechanism with a separate rotation mechanism, and is used for more substantial material such as masonry or concrete.
• Cordless drills are electric drills powered by rechargeable batteries; these drills are available with similar features to an AC mains-powered drill.

Video credit: DeWalt TV / CC BY-SA 4.0

Standards

• BS 2556 - Hand and breast drill specs
• ISO 11148-3 - Safety for handheld, non-electric drills
• IEC 60745-2-1 - Safety for handheld, electric drills and impact drills

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