Different Voltages—Cordless drills are measured in volts. Drills are available in everything from around 2 volts (for a cordless screwdriver) to 20-volt tools. Higher voltage means heavier weight, so consider buying a tool that will meet 80% to 90% of your needs. Twelve- to 18-volt models are the most popular, and they'll usually meet most homeowner's work needs. Higher voltage means more torque-spinning strength to overcome resistance. Over the last decade, top-end voltage has increased from 9.6 to 18V, but the range of models include 6, 7.2, 9.6, 12, 14.4 and 18V. Today's higher-voltage drills have enough power to bore big holes in framing lumber and flooring. That's impressive muscle. But the trade-off for power is weight. A typical 9.6V drill weighs 3 1/2 lbs., while an 18V model weighs up to 10 lbs. Drill Bits—you secure the drill bit on the drill using the keyless chuck. Make sure that on the adjustable clutch that the setting is turned to drill. Simply secure the drill bit in the chuck and drill into the piece of wood or the wall. Screwdriver—You can also use your cordless drill as a screwdriver. This is where the adjustable clutch comes in. You see all these numbers? Adjustable clutch settings are a valuable feature. The clutch reacts to the resistance of the screw, which changes as the density of the material changes, allowing you to drill holes of consistent depths. Adjusted properly on identical scrap material, a clutch can keep you from driving a screw too deep. An adjustable clutch can also reduce the possibility of stripping a screw head or snapping a screw off altogether.
