TOOLS : The Right Electric Drill Can Work Overtime--to Grind, Strip and Buff

Every home workshop should have at least one electric drill, a versatile tool that can drill holes in metal, wood, plastic, masonry, ceramics and even glass.

An electric drill can also take dozens of accessories that let you sand, grind, shape, strip, buff, sharpen, cut holes, drive screws and more. For normal home use, heavy-duty features are not usually necessary.

Buy the best quality drill you can afford. Your best guide is a reputable manufacturer.

Size and Speed

Electric drills come commonly in one-quarter-, three-eighths- and one-half-inch sizes. Size is determined by the largest bit shank that will fit into the drill’s chuck (the part that holds the hole-cutting bit). Drill power varies with size and model but generally ranges from one-fifth to one-half horsepower. Typically, speed decreases with increased size, but torque (turning power) increases.

Because of its high speed, the one-quarter-inch drill is good for boring small holes and doing other lightweight jobs. But the three-eighths-inch drill is usually a better choice for the homeowner because it can handle more jobs.

With more power than smaller drills, the one-half-inch drill can bore larger holes without overloading its motor. It turns at a slower speed, however, and is not so well suited for operations such as sanding and grinding, which require high speed.

For best results, get a reversible model with variable-speed control. Reverse is useful for backing wood bits out of deep holes, removing screws, and reversing rotation on abrasive products to lengthen their life. Being able to vary the speed of the drill lets you select the best drilling speed for the job and use a wider variety of special attachments.

Cordless Drills

Many do-it-yourselfers invest in a cordless drill as either their only drill or as a second drill. Although portability is helpful, it’s unlikely that a cordless drill will have enough lasting power for heavier-duty operations such as sanding. But many models will drill more than 100 holes after a charge of only a few hours.

One type of cordless drill has a battery built into its handle; recharge it by connecting a transformer to the drill and plugging it into a wall outlet. The other type has a removable battery pack that is recharged in a separate unit.

For cordless drills, use only the battery and charger that came with the tool; never switch batteries or chargers. Avoid dropping the battery and never use a battery-containing tool as a hammer. For longer battery life, turn the drill off when you are not actually using it.

Don’t charge or store a cordless drill where the temperature is below 40 degrees Fahrenheit or above 105 degrees. Batteries rely on chemical reactions that slow down in the cold and stop altogether below freezing. In high temperatures, vapors are released from the battery pack and its storage capacity is diminished. Occasionally, let the battery discharge completely before recharging, or in time it may resist taking a full charge.

Drill Cords

Most drills are equipped with three-wire grounding cords (with three-prong plugs) to protect the user from shock in case of an internal electric fault. A drill with a two-prong plug should be double-insulated. This means that the outer shell and the chuck are completely insulated from the internal wiring.

Some drills come with a plastic or steel carrying case that may also hold an assortment of accessories.