Are you the proud owner of a brand-new portable electric power drill? Or are you hauling the old one out of the closet for a special project? Before you plug it in and pull the trigger on your latest home improvement task, know this: A drill is a precision instrument with a lot of power that can cause serious injury if not used correctly.

For example, a spinning power drill scalped a Czech Republic woman after her ponytail got caught in the device earlier this year. And last year, a construction worker nailed himself to a roof when he dropped his drill, sending the rotating bit straight through his foot.

Here are some precautions you should take to avoid letting your handy power drill get the best of you.

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Dress for success

Drilling can throw up shards, debris and even pieces of a broken drill bit. Wear either safety glasses or goggles, suggests the North American Retail Hardware Association, and consider a face shield.

Ear muffs or plugs are also important because drills are noisy machines. They average 95 decibels, about the same as a quiet motorcycle or a noisy lawnmower, according to the Center for Hearing and Communication.

Don't wear anything that can get caught in the drill, such as a tie, jewelry or loose clothing, according to the University of California. Tie back long hair or put it under a cap.

Watch your fingers

Don't place your hands near a moving chuck or bit, and resist the temptation to use your fingers to stop them from rotating. That's what the off switch is for.

Don't walk around with a running drill. Instead, turn it off and keep your finger off the power switch. 

Beware the power of electricity

A small power drill uses 30 times as much electricity as is necessary to kill a person, according to the Centers for Disease Control.

Don't operate a power drill where wet or muddy conditions can compromise your safety. In 2011, a man working on a house on the Texas coast was electrocuted when he fell into a body of water while holding a turned-on drill.

Before you start your project, inspect behind or inside of the “stock” (the surface you’ll drill into) for wires and water lines. If you can't see inside or if you're not sure what's in there, use a scanning device, according to the North American Retail Hardware Association.

More advice:

  • Make sure it’s turned off before plugging it in, inserting a battery, changing bits or making adjustments.
  • Use only batteries, battery packs and battery re-chargers specified by the manufacturer.
  • Don't carry it by the power cord. Before drilling, check the cord for fraying or damage.
  • Never operate a power drill if flammable fumes are present.

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Bits and pieces

If you need to change bits, be careful when removing one. Bits are sharp and, after use, can be hot to the touch.

If the bit gets stuck in the stock (remember — that’s the surface you’re drilling into) and refuses to spin, the force of the motor could cause the entire drill to start spinning." If this happens, it could fly right out of your hands. Let go of the trigger immediately and unplug the drill. To avoid this, take these precautions:

If you think the bit is in danger of getting stuck, don't use the “lock-on” feature, which locks the trigger in the “on” position. 

If possible, clamp the stock in place using a vice or something similar so it won't start spinning either.

Never drill with one hand while holding the stock down with the other, especially if the stock is small, according to the Canadian Centre for Occupational Health and Safety

Then, while you're drilling:

  • If the bit won't penetrate properly into an object or the rotation slows down, don't try to force it in. You can damage the bit or even overheat the motor.
  • Instead, try easing on the pressure to see if the drill starts cutting more smoothly. If that doesn't work, try a different bit.

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David Arv Bragi is a freelance journalist and marketing consultant. He has been writing about health and safety issues since the 1990s and currently lives in Portland, Oregon.