When they first came on the market battery-powered impact wrenches seemed a novelty - the kind of tool suburban wives buy their husbands. The same could be said of cordless drills until the tool industry grew the size and power of batteries. Today, cordless drills readily compete with their corded counterparts when it comes to power.
Although pneumatic impact wrenches deliver more maximum torque and often cost less than their battery-powered cousins, the latter don't need large air compressors and hose lines to operate. Convenience and portability are the competitive values cordless impacts offer. And the 14.4- and 18-volt versions of these tools pack enough oomph to back a rusted 1-inch nut off an implement bracket in the field.
As a result, cordless impacts are readily earning a spot behind pickup seats and in field toolboxes. "I seem to use mine all the time," says Darrell Geisler, who got the opportunity to test an 18-volt, 3/4-inch shaft Milwaukee cordless impact for Successful Farming magazine.
The Elkhart, Iowa, farmer admits he was dubious of the tool's abilities. "It seemed a glorified toy," he recalls. "Sure, it won't do the work of a heavy-duty pneumatic impact. But out in the field, there is nothing handier for adjusting a planter or cultivator."
Geisler is not alone in those sentiments. Online discussion groups are singing the cordless impact's praises (see sidebar on the next page). Like Geisler, they recommend purchasing nothing less than a 14.4-volt model. But the 18-volt models are best for farmwork, they nearly all agree. "Mine has a 3/4-inch drive, which I think is a must," Geisler adds.
The comparison table above lists all the 14.4- and 18-volt cordless impacts on the market with 1/2-inch-drive anvils. Common features among these models include reverse operation and variable speed. Both 9.6- and 12-volt models are also available as are impact wrenches with 1/4-, 7/16-, 3/8-, and 3/4-inch square drives.
Other features worth examining are hex driveshafts (for fast changeovers from socket adapters or auger bits), electric brakes (that stop the tool when the trigger is released), externally accessible and replaceable brushes and armature, metal housing over the front drive, and fan-cooled motors.