Five elements compose the exterior of a basic power drill: a safety latch, a reversing switch that alters the direction of the drill, a torque adjustment, a chuck to keep the bit from moving and a handle. The hard plastic or metal drill housing contains a simple motor that turns the drill bit so you can bore holes into metal, plastic or wood. You can attach a screwdriver tip on the end of the bit to install (or remove) screws. Some drills feature cords that plug into a 110-volt electrical outlet, while others are battery-powered.

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How Does a Power Drill Work?

Manufacturers typically make cordless drill handles from polymorph, a material that imparts a comfortable grip and rests easily in your hand. Drill housings may be made out of metal, but most companies construct the body of the drill from polythene, which can endure high temperatures without melting. Electric drills and cordless drills are usually pistol-shaped.

How it Works

Pulling the trigger of your power drill completes an electric circuit---much like you do when you turn on light switches. Both devices work on a similar principle. A metal piece on the opposite side of the trigger (the portion inside the drill) conducts electricity from your power source (a battery or the wall socket to which your cord is connected) to your motor. Electricity powers the motor inside your drill to turn the bit or the screwdriver attachment.

When you push the drill into a surface, the bit slightly penetrates the material. Rotating gradually feeds the drill bit into the surface and produces enough friction to slice or grind the material below and around the bit to form a neat hole.

Putting Theory Into Use

Unplug the drill. Slide the right bit or screw tip into the chuck, and then tighten it. Some drills provide an Allen wrench or other tightening tool, or the drill may require a hand tightener. Align your torque adjustment so that the bit won't slip. Plug in your drill and place the point where it belongs. Turn on the drill and start making your hole. Push the drill forward as the bit rotates. Maintain a steady hand to form an even, round hole.

Keep it Functioning

Choose the right bit for the job. Using the wrong bit can damage your motor and your drill won't work. Store the bit in a dry area. Dry everything off before you put it back into the case.