My college rugby coach used to encourage the small guys on our squad (me) by saying, "It doesn't matter how much dog is in the fight. It only matters how much fight is in the dog."
While Coach Ortale's phrase fired me up in my rugby days, it's also an apt description of cordless impact drivers. They're small, yes, but also powerful and fast. And, compared to cordless drills, they're easier to use and can do more things. While about half the size and three times the torque as cordless drills, impact drivers are at home bulldogging foundation bolts or setting cabinets. And, since getting my hands on impact drivers about two years ago, I find my cordless drill spends more time in its box than ever.
The nine drivers in this test range from 12 to 18 volts. I tested four 12-volt models: the Hitachi WH12DM2, Makita 6916DWDE, and Panasonic's EY6506NQKW and EY7201GQW; four 14.4-volt tools: DeWalt DW054K-2, Hitachi WH14DMB, Makita 6932FDWDE, and Milwaukee 9081-22; and the industry's only 18-volt unit, the DeWalt DW056K-2. I drilled and drove in heavy- and light-duty applications on site, turning 1/2-by-6-inch lag screws and cinching carriage bolts for a sundeck and crunching down foundation bolts on a stem wall. I also hung interior doors, installed vinyl replacement windows, and screwed down a 1/4-inch plywood subfloor for vinyl sheet. I drilled small pilot holes for door hardware and predrilled deck parts. Then, I went into the shop for head-to-head drilling and screwdriving, timing how long each unit took to drive a 1/2-by-6-inch lag, counting how many 4-inch Timberlock screws each tool sank, and recording drilling speed through double 2-by.
Heavy-Duty Work. In my past life as a home improvement contractor, I built several sundecks a year and relied way too much on wrenches and ratchets to tighten bolts and lock together handrails and posts. For the decks I've built since then, I've come to rely on impact drivers–mini powerhouses that make the work faster and easier. Each unit in the test group proved invaluable for getting carriage bolts snug, driving lags, and sinking 3-inch deck screws by the fistful. They fit into joist bays and can drive a screw straight through a deck board if the driver bit is long enough. I also used them to predrill deck parts with sharp 3/8- and 1/2-inch spade bits, which proved easy work for them.
The larger-bodied, 14.4- and 18-volt tools felt more solid and vibrated less while driving lags than some of the 12-volt tools. The Hitachi 12-volt WH12DM2 showed big power here and drove lags like a larger tool. The Panasonic EY7201GQW worked nicely here, too. The Makita 6916DWDE and Panasonic EY6506NQKW struggled a bit with the lags (the Makita was slow and the Panasonic wobbled around the screw head noticeably).
These tools all have 1/4-inch hex drives instead of keyless chucks–and they're great. Makita's is particularly easy to grab and release.
The whole group also cranked down foundation bolts about 100 times faster than any ratchet or wrench I've ever used. Plus, there's no reaction torque when the nut seats, as there is with a drill. This is nice for keeping your shoulder joint in its socket. The only limitation was on bolts that stuck higher above the mud sill than the depth of the socket. Still, across the range of heavy-duty applications, all the tools in the test group performed well.
Light-Duty Work. Each driver also performed nicely in lighter applications like door hanging and installing windows and cabinets. While these tools have a truckload of power and speed, their variable-speed triggers are sensitive enough to snug pan-head screws to vinyl window jambs or cabinet backs. It's even easy enough to set drywall screws properly for small repairs. For very gentle work, like installing cabinet hinges or some woodworking tasks, however, a lower-rpm, lower-torque cordless drill is a safer bet.
On these lighter-duty projects, the 12-volt tools excelled. While the 14.4s and 18-volt worked just fine, the 12-volt models are so light, compact, and easy to hold that I just want to pick them up, particularly the Hitachi WH12DM2 and Panasonic EY6506NQKW. And by comparison, these impact drivers made my otherwise perfect 18-volt cordless drill feel larger and more awkward than it had before I started this test.
Rubber bumpers on the Panasonic EY7201GQW are nice for working around scratchable material like countertops.
In the shop, I staged power and run-time tests so I could evaluate the tools all in one place, at the same time, and in the same material. I also took a closer, side-by-side look at the balance, fit and finish, bit exchange, battery exchange, toolbox, and extra features on each tool.
Power & Run Time
Drilling. To get a better sense of head-to-head performance, I simulated a deck-ledger assembly with treated 2-by, 3/4-inch plywood, and the driest, hardest piece of Douglas fir 2-by I could find. Since each tool sailed through deck parts on site with sharp 3/8- and 1/2-inch spade bits, I used a 1-inch spade bit. While all but the 12-volt Makita and Panasonic EY6506NQKW made it through the stack, it wasn't pretty for any of the tools: Each shook excessively and bogged down. For any hole over 3/4-inch, it's best to use a cordless drill/driver or plug-in. Smaller holes were a breeze.
Driving Lags. If you build a deck a day in subdivisions full of production houses, you may want to dedicate an electric impact wrench to your crew. These cordless drivers may not be up to day-in, day-out production-driving work like that. But if you're looking for a tool that can step up to deck work, while also shining on all kinds of other projects, then these small drivers are terrific time-savers–and you may find you're leaving the bulky corded impact driver in your shop.