Extra Controls. Impact drivers are notorious for having a steep learning curve. With soft screws–brass and even steel hinge screws–it’s easy to shear the heads right off. Hilti, Hitachi, and the Panasonic 7540 try to help with an extra control to lower the driving and impact speed, thus reducing torque. Panasonic has three electronic speed settings, and Hilti has a two-speed electronic switch. The Hitachi has a more primitive speed reduction switch that simply limits how far the trigger can be pulled. Despite the good intentions behind these controls, they didn’t see much use on the job. My guys want to keep moving, and they have already learned to feather the trigger for control rather than stopping to push buttons. But dialing down the torque could flatten out the learning curve for others.
Shop Testing
In the field, we learned these tools can drive a lot of screws–between 400 and 500 2-1/2-inch flooring screws on a single charge. Not wanting to drive 6,000 screws for our battery duration test, we settled on something a little tougher: 1/4- by 3-inch Simpson SDS lags into fir 4-by-4s.
Even at that, it took nearly two days of driving to complete the head-to-head testing. Each battery was fully charged, and every tool was given 15 minutes to cool down, as they heated up midway through the testing. Because some lights were trigger activated, we turned on the manually activated lights just in case the battery drain from the LED influenced the results.
While testing how many lags each tool could drive on a charge, we also timed driving speed by averaging the stopwatch times for eight lags with each tool. See the spec boxes for the results.
The Winner
Because most of these impact drivers went through a truckload of screws on one battery–more than anyone would drive in one day–the choice of tools really came down to comfort and features.
The Makita BTD142HW compact driver is the clear winner. Every carpenter in the field chose it over all the others, with its light weight being a bigger factor than big muscle. And though the compact battery with half the capacity of the others did do well for its size in our demanding shop test, keep in mind that the primary job of these tools is driving medium-sized wood screws. For this and our common tasks of installing cabinet hardware, door hardware, setting hollow-metal doors, and installing cabinets, the 142 has all the guts you need, without carrying around any more than you have to. And with its 15-minute charge time, you couldn’t outpace it if you tried.
Just outside the winner’s circle is the Makita BTD141, which is nearly identical to its sibling except for a 4% higher torque rating and a full-sized battery for guys who don’t want to change it every day. Both batteries and tool bodies are totally interchangeable, and their four-pole motors tested equally for performance.
Second place goes to the Panasonic EY7540LN2L for its top speed and duration numbers and very comfortable design. It is just a little bigger than the winner and is the second lightest. All this performance comes out of a 14.4-volt tool. It must have something to do with its advanced, brushless motor technology that is unique to Panasonic in this test.
The third place tools are the DeWalt DC827KL, Hitachi WH18DL, and the Panasonic EY7542LN2L combination driver, all comfortable tools with strong performance. All the other tools occupy the next tier except for the last-place Ridgid, which just couldn’t keep up despite its size and published specs.
Gary Katz is a finish carpentry specialist and writer in Reseda, Calif., and is a member of Hanley Wood’s JLC Live construction demonstration team.
Little Tools, Big Punch
Though not designed for heavy work like the tools in the test, one of these versatile models may deserve a place in your toolbox.
The pocket-sized, 10.8-volt Bosch PS40Z is a must-have gadget tool, and it doesn’t need a belt hook–it fits right in a nail pouch. I use it for driving pocket screws, installing locks and strikes, putting up towel bars, and endless other small jobs.
Another handy tool, especially for installing drawer guides in tight quarters, is a right-angle impact driver. I’ve used the 12-volt nicad Ridgid R82233 for a couple of years, and the new 18-volt LI Makita BTL061 carries an even bigger punch at about three-quarters the weight. Its full-finger grip trigger is supersensitive and controls speed well, so that even the smallest screws start easily. And best of all–especially when I’m working in cabinets–it has a bright LED light.
The 7.2-volt Makita TD020DSEW is the first stick driver with an impact feature and is great for small fasteners that might need the break-free kick of an impact without stripping the screw head, such as on painted-over switch plates. Stick drivers are a favorite of the electrician, and the skinny shape helps it fit into panel boxes and other tight spots. It comes with a nice holster, but it could easily slip into any pocket.
The Panasonic EY7541LN2L is very similar to its high-ranking brand mate, but is actually an impact wrench with a 1/4-inch bit holder/adapter that snaps on to its 1/2-inch socket-driving end. This wrench version has the highest-rated, 1640 inch-pounds of torque, and tested well with 106 lags driven at 7.0 seconds each. The adapter accessory can fit other brands and types of 1/2-inch impact wrenches, and makes for a quick change to impact driver use.