Glossary Cordless drills
Amp Rating
For corded models only. The maximum current, in amperes, at which the drill operates.
Batteries
The number and type of batteries provided with the drill. All are rechargeable. The more common type is denoted NiCd, for their nickel-cadmium components. Nickel-metal hydride (NiMH) batteries boast added energy for their weight and can be disposed of with regular refuse; NiCads must be recycled.
Chuck Capacity
Indicates the largest size full-shank tool (twist drill bits on power drills) that a drill's chuck can hold. The most common size is .375 inch (3/8 inch), but some drills can handle bits with shanks up to .5 inch (1/2 inch).
Chuck Key
A small L- or T-shaped wrench used to open or close the chuck on some drills. Most newer cordless drills have a keyless chuck, which lets you tighten the jaws with a few twists of the hand. Some require two hands to tighten the jaw, and others can be tightened with one hand.
Clutch Settings
Virtually all cordless drills have settings that can limit maximum torque and so prevent the drill from driving a screw too far into soft wallboard, say, or mangling a screw's head or threads by continuing to turn after the screw is in. The more settings, the more precise the torque control.
Cordless
Powered by a battery, allowing you to work without a power cord. Cordless drills accept the same drill bits as corded tools.
Drill Type
Most corded drills are simply drills; they drill holes. Many cordless models come with screwdriver bits and are termed drill-drivers. Hammer drills can provide impact action, for faster drilling though masonry. Right-angle models have a chuck mounted at 90 degrees, which is handy for drilling between studs.
Maximum RPM
Two and three-speed cordless drills have a maximum speed of about 1,500 revolutions per minute (rpm) or more, and can easily handle rapid drilling. Many lower-priced, single-speed cordless drills can manage only about 600 to 800 rpm, compromising their performance.
Reversibility
Indicates the drill bit can be reversed to turn counterclockwise. Allows you to remove screws and nuts. It also makes removing a drill bit easier if it happens to stick in the work material.
