Cordless Impact Driver

Impact drivers have been a staple of the automotive repair world. If you’ve ever had a tire replaced, the lug nuts were spun off and on by these noisy, powerful air-driven tools. Now they have been redesigned for driving woodscrews and lag bolts. These tools are cordless, much more compact than drills, and have features that give them significant advantages over the standard drill for driving fasteners. Though many power tool manufacturers are now producing this class of tool, I’m going to describe a current model from Panasonic, because they are considered the leader in cordless technology.

The EY7201 Cordless Impact Driver is a deceptively powerful tool. With most manufacturers racing to see who can market the highest voltage tool, its 12-volt rating would seem to indicate last year’s technology. This is a misconception: Voltage ratings for cordless power tools mean nothing when quoted without amp-hour ratings, arguably a more important piece of information if one is to compare the quality of battery-operated tools. Panasonic’s 3.5 amp-hour rating for their nickel-metal batteries is the best in the industry.

Then there is the issue of motor efficiency, that is, how the tool’s motor converts this energy to motion. Again, Panasonic’s permanent magnet motors are the most efficient in the industry, sending virtually all the battery’s energy to the motor. What makes the EY7201 unique is a dual-mode power switching feature which allows one to set the impact torque hard or soft. The soft mode is particularly useful for setting smaller screws without breaking off their heads. Finally, this tool’s electric brake, extra battery, 55-minute recharge time, and ergonomic design make it an essential item if you drive a lot of screws.

Suggested retail $249
www.panasonic.com