Driving screws is a piece of cake for impact drivers, but brute torque can be overkill for some jobs. The selectable-speed driver is a new breed that allows you to choose the torque that suits the task. Kevin Bittenbender heads the crew that builds timber-frame homes at Bensonwood, in Walpole, New Hampshire. They put six selectable-speed models and 10 single-speed ones to the test. Here's their verdict.
All drivers tested by driving 4½-inch SDS structural wood screws into 6-inch-thick solid pine; 6-inch SDS screws into Douglas fir engineered lumber; 2 ½-inch deck screws into spruce 2x4s and oriented strand board (OSB) sheathing; and by drilling ¾-inch-diameter holes into spruce 2x4s.