Few power tools are as versatile as a handheld drill. It makes holes in wood, steel, non-ferrous metals, concrete, drywall, plastics and goodness knows what else. It makes threaded holes to accept a machine screw. It drives any number of threaded fasteners from wood screws, to drywall screws to concrete screws. It not only drills specialized holes for pocket screws, it drives the screws themselves, and you\u2019re one step closer to being a furniture maker. Use a nut driver bit or a socket to zoom through assembly work, tightening a bolt head or a nut. Specialized drills have a chisel setting that allows the tool to work in a percussion mode without rotary action at all. Here\u2019s what you need to know to select the right drill.Cordless DrillsWhat it is: Often called a drill/driver. It\u2019s a battery-powered hole maker and a fastener driver for screws, nuts and small bolts. It\u2019s equipped with a clutch that disengages the drill\u2019s drivetrain when the tool reaches a specified amount of torque (turning force). By disengaging the drivetrain at that point, it prevents stripping the fastener head, snapping the fastener off or driving the fastener right through a piece of wood.Where to use it: Use these anywhere you need to make a hole or drive a screw, set a nut or tighten a small bolt.Mechanical insight: Four things determine the work that these tools do. Battery voltage: It ranges from 8 volts all the way up to 60 volts with 12-volt and 18-volt the most common voltages. The larger the battery/motor voltage, the heavier work these tools can do. Increase the voltage and you can drill larger diameter or deeper holes, drive larger screws or tighten a bigger nut.Battery size: This is measured in amp hours. The larger the battery\u2019s amp hours, the longer you can operate a cordless drill.Functions: Cordless drills are always equipped with a clutch that allows the tool to drill or drive, but it may also be equipped with a hammer function that allows the tool to drill a hole in concrete or stone using a carbide-tip masonry bit.Chuck size: Cordless drills are equipped with two different size chucks, 3/8 inch or \u00bd inch. Choose a product with a larger chuck diameter if you expect to routinely drill larger diameter holes. Purchasing power: There\u2019s no shortage of great deals on cordless drill/drivers, hammer drills and specialty tools.Pro Tip: Consider buying a factory-reconditioned tool at a steep discount. Sometimes these are essentially brand new tools that have no more than a few minutes or a few hours of run time. They have to be cycled through the factory reconditioning process because they are no longer considered a new product. Impact DriversProfessionals and homeowners alike find themselves using impact drivers instead of cordless drills, especially with the advent of bit sets with hex-shank accessories that are specifically designed to withstand the stresses that these drivers impose on a bit. Impact drivers are high-torque tools primarily used for driving screws and tightening nuts (an operation known as nut setting). Their chuck accepts only bits with a \u00bc-inch hex shank. You either pull up on the chuck sleeve to insert a bit or you just slip the bit into the chuck. These tools are lighter and smaller than drill drivers, and although they are not as versatile, they will perform many of the same functions. Since their torque output is higher than a typical drill driver, they get through work more quickly.Purchasing power: Like cordless drills, great deals are to be had on some of our favorite impact drivers if you know where to look. Corded DrillsWhat it is: A drill powered by a 120-volt motor and a conventional 3-jaw chuck. These drills are traditional products and are often used for heavy-duty applications in drilling holes in wood, concrete, and steel. Since they are not equipped with a clutch, they are not designed to tighten or drive fasteners. They excel at hole drilling.Where to use it: Use these anywhere you need to make a hole, and especially in places where the drill\u2019s size will not limit its usefulness. Where the drill\u2019s size might pose a problem, see the specialist sidebar for right-angle drills.Mechanical insight: Four things determine the work that these tools do. Amperage: Amperage is the flow of electrical current. Corded drills come in a range of motor capacities from 6 to 13 amps. The more amperage they draw, the heavier the work you can expect to do with them.Chuck size: Corded drills will have a 3/8, \u00bd-inch, 5/8-inch or \u00be inch chuck. Choose a chuck with a larger capacity diameter if you expect to routinely drill large holes.Functions: Corded drills may or may not be equipped with a hammer function for drilling concrete and stone.Most corded drills are variable speed to help you better drill a combination of materials. But a few are single speed.Purchasing power: There\u2019s no shortage of great deals on corded drills, hammer drills, and specialty tools. You're going to want to buy a little more drill than you think you might need, but don\u2019t go too crazy, either.