Popular Woodworking 2001-10 № 124, страница 10

12voltdrills

Bigger is not always better in the world of cordless drills. Figure out how much power you need without breaking your wrist.

Every year as we travel the country to woodworking shows, we're shocked and amazed at how big and powerful cordless drills have become. It's fair to say there's a small part of us that's impressed with the performance of these heavyweights. But the small bones in our wrists know better. For most woodworking, a 12-volt drill is more than enough.

If you're a contractor or professional deck builder, then your objections have been noted, so go ahead and purchase that 24-volt workout machine. For the rest of us, here's what to look for in a 12-volt drill.

Handle Design

Most cordless drills these days are T-shaped, with the handle coming down near the middle of the drill. A few are pistol-grips, where the han

dle comes down from the back end of the drill, like on most corded drills.

T-handle drills are more balanced and will stand upright (usually) on your bench. Pistol-grip drills allow you to put more of your weight behind them — usually not a big issue with woodworking.

Torque

Cordless drills with 12-volt batteries are available with 1 amp-hour batteries all the way up to 3 amp-hour batteries. The amp hours are analogous to the gas tank on your truck. The bigger the tank, the farther you can go. More amp hours give you more run time. Also critical is the amount of torque produced at the chuck. Torque is measured in inch-pounds for cordless drills; higher numbers are better. The more

SHOPPING GUIDELINES

12-volt drills

• Get the most torque and highest amp-hours you can afford.

• Make sure your drill is variable speed. This will be listed on the side of the gearbox as, for example, 1-1,000 rpm. Drills without variable speed are more difficult to control.

• A "high-" and "low-" speed selector is handy for setting your tool to drill holes or drive screws.

• Don't get worked up about the number of clutch settings. Six or more will be enough.

On pistol-grip drills, the handle comes down at the rear of the motor. You can put more of your weight behind the drill with this arrangement, but this should rarely be necessary with these drills

torque you have, the less likely you're going to bog down in a hole.

Battery Type

As you shop for a drill, you'll notice that some come with Nickel Cadmium (NiCad) and some with Nickel Metal Hydride (NiMH) batteries. Which is better?

According to battery experts, Nickel Metal Hydride technology gives you more run time in the same size battery cell.

NiMH batteries are also more environmentally friendly. The cadmium in NiCad batteries must be disposed of in a controlled manner. NiMH batteries are more expensive, and some manufacturers haven't jumped on the bandwagon yet saying the technology isn't perfect.

Speeds

All but the least expensive (and lightest duty) drill/drivers offer some nice features you won't find on many corded drills, including variable speeds.

Many drills are available with both variable speed and two-speed capability. They're different features that work together. Variable speed is the ability to control infinitely the rotations per minute (rpm) of the chuck by increasing or decreasing the pressure on the trigger. This allows better control over your work, to keep a drill bit from wandering off the mark, or to start a screw in the right spot. The two-speed capability allows the drill to be switched from one speed range to another, like switching from first to second gear in your car. Torque in low speed is higher, but the top rpms are lower. This is best for large-diameter drill

10 Popular Woodworking October 2001