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 Although 12-volt cordless drills have enough power for most woodworking tasks, it's difficult to resist the lure of the latest generation of 14.4-volt drills. Many of these tools weigh about the same as 12-volt models did only five years ago, yet deliver more twisting force and drive more screws before they need recharging.
There's another reason to consider stepping up in voltage: Many 14.4-volt drills sell in combo kits with other handy cordless tools, such as power planers, jigsaws, and circular saws. High-voltage batteries (18 and 24 volts) will power even more demanding tools, but the added weight (and cost) makes them less attractive to woodworkers.
Five key measures of a quality cordless drill/driver:
- Torque. When most of us talk about a drill's power, we're really talking about how much rotational force, or torque, it can produce. Manufacturers rate their maximum torque in inch-pounds.
- Run time. If torque is like the horsepower of your car's engine, run time is like mileage—how far it will go on a tank of fuel. The "tank size" of a battery pack is measured in amp hours. However, efficiency comes into play too. So just as a Honda will go farther than a Hummer even though it has a smaller tank, a high amp-hour rating doesn't guarantee long run time.
- Chuck grip. With 1/4" hex-shank drill and driver bits available practically everywhere, a drill chuck's ability to hold fast on a round-shank bit means somewhat less than it used to. Still, drills with this much power should be able to grip a round-shank drill bit well enough to keep it from slipping.
- Clutch consistency.
All of the tested drills have an adjustable clutch between the chuck and the nose of the drill. A clutch stops the chuck from turning when it encounters a set amount of resistance, preventing the drill from shredding the screw head, breaking the screw, or driving it too deep into the wood.
- Batteries and chargers. The drills that topped our run-time tests both use nickel-metal hydride (NiMH) batteries. However, nickel-cadmium (NiCd) batteries were close behind, so don't make battery chemistry an issue unless cost or extreme temperatures are major concerns to you.
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