Power Play: Tools That Deliver

Bosch

In the past 2 years, manufacturers have focused on making cordless power tools lighter and smaller than ever before. Thanks to the latest lightweight lithium-ion batteries, we’ve seen cordless drills that are as light as 1.8 pounds and as small as 6-3/4 inches in length.

Most of these new models are rated at 12 volts of power, but you can expect them to perform as if they were 18 volts or better. That’s because manufacturers have discovered ways to squeeze more power and torque out of their smaller tools and batteries by tweaking conventional motor design. But manufacturers aren’t resting on their laurels, and brushless motors are their solution to pull even more power out of their power tools.

POWERFULLY SMALL. You should be aware that not every cordless drill that has “compact” in its description lives up to that name. That’s because manufacturers continue to slap the word “compact” on anything that’s less than 10 inches long, despite the fact that the average length of a cordless drill is 8-1/2 inches.

In the past 2 years, seven manufacturers—Bosch, DeWalt, Festool, Hitachi, Makita, Milwaukee and Porter-Cable—introduced 12-volt drills that measure 7-1/2 inches or less in length. You can find these new models in all price ranges, and the torque ratings for these power tools range as high as 455 inch-pounds. That’s enough power to drill through concrete or heavy steel.

Although drills that deliver that much torque weigh at least 4.3 pounds, other new slimmed-down models weigh around 2.0 pounds. But these lightweight models generate only 250 inch-pounds of torque at most. In other words, if you want more torque, the trade-off is a heavier drill that might cramp your hand on occasion.

But that trade-off could be a thing of the past in the next year or so. Brushless motors—direct-current motors where no metal contacts the electrodes—have been used for years in the industrial-tool sector to achieve higher torque ratings, longer tool life and more energy efficiency. Brushless motors had been too expensive to incorporate into consumer power-tool models.

But Bosch, Hitachi, Makita and Panasonic introduced cordless impact drivers that have brushless motors in the past year, and Hitachi took things a step further by bringing brushless technology to a cordless drill. Three other manufacturers say they expect to join the shift to brushless power-tool motors in the next year.

And make no mistake: Brushless models are expensive. They typically cost as much as 80 percent more than do conventional models that have comparable no-load speeds. All of the manufacturers with which we spoke predict that the price of power tools that have brushless motors will come down in the next 2 years, but no one is willing to project by how much.

Manufacturers claim that brushless motors can pull as much as 20 percent more run time out of the same batteries, because the lack of brushes—and thus the lack of contact with the electrodes—reduces the friction that eats up energy. The independent electrical engineers with whom we spoke couldn’t pinpoint an exact amount, but they confirmed the premise that brushless motors produce more power and consume less energy than conventional models do.

Brushless motors also give you increased control over speed and torque settings. That’s because brushless motors are controlled by microchips, which allow for more motor-speed settings—as many as eight individual operating speeds on a power tool. Models that use conventional motors have only two to four operating speeds.

Unfortunately, other brushless claims are more suspect. For instance, manufacturers tout the benefit of not having to pay for brush replacement, as consumers might have to do with a conventional model. But tool-repair experts tell Consumers Digest that this benefit is negligible. The cost to replace power-tool brushes is only around $20 for most models, and brushes last an average of 2,000 hours. Even if you kept your tool in constant motion for as much as 3 hours per week, it still would take you 12 years to wear out the brushes!