I started out in the trades right before the cordless revolution, when many of us had at least two corded drills: a powerful 1/2-inch one with a side handle for the big stuff and a lightweight 3/8-inch model for the rest. Just because we've ditched the cords for most of our drilling and driving doesn't defeat the logic of having both sizes. I was reminded of that recently when I used my 1/2-inch 18-volt Milwaukee hammer-drill - which weighs 6.2 pounds - to bore lots of 1/8-inch pilot holes in composite decking and cedar; a lightweight 3/8-inch cordless drill/driver would have handled the job easily while giving my forearms a break.
Weighing just 2.1 to 2.6 pounds, the latest 12-volt 3/8-inch subcompacts are not only small and light enough to ride in a pocket or a toolbelt, but their surprising power and advanced features can make them an ideal complement for remodelers, electricians, plumbers, and hvac installers and a prime tool for finish carpenters and architectural woodworkers.
View Comparison Table, pp. 2-3
For this tool test, I was shipped seven subcompact kits: the Bosch PS31-2A, the DeWalt DCD710S2, the Hitachi DS10DFL, the Makita FD02W, the Milwaukee 2410-22, the Porter-Cable PCL120DDC-2, and the Ridgid R92009. After drilling enough holes and driving enough screws to numb the tip of my trigger finger, I've summed up their power, runtime per charge, and ease of use.
Drill/Drivers Versus Drivers
All the subcompacts I tested have a low and high variable-speed range and a versatile 3/8-inch keyless chuck. That's an important distinction, because Bosch, DeWalt, Hitachi, Makita, and Milwaukee also make similar subcompacts with 1/4-inch hex chucks. Bosch's and Makita's hex-chuck models deliver the same torque and dual speed ranges as their 3/8-inch models, but those from DeWalt, Hitachi, and Milwaukee have less torque than their 3/8-inch counterparts and a single speed range with a top speed that's too slow for drilling most holes.
Also, many common drill bits don't have hex shanks. DeWalt calls its hex-chuck model, which delivers 0 to 1,050 rpm, a screwdriver rather than a drill/driver and targets it for 98 percent driving and 2 percent drilling.
Most of the operator's manuals give drilling and driving capacities, and the figures are pretty consistent; you can routinely bore holes up to about 1/4 to 3/8 inch in diameter in mild steel, use spade bits up to about 3/4 to 7/8 inch in diameter, and drive common wood screws. (By comparison, the manual for my Milwaukee 18-volt hammer-drill says it can bore 1/2-inch holes in steel, power 1 1/2-inch spade bits or 2 9/16-inch hole saws, and drive 1/4-inch screws).
These are all practical numbers for repetitive work. Equipped with a 3/4-inch spade bit, the subcompacts could consistently bore holes through 2-by Douglas fir at high speed in about five to 10 seconds, and they drilled a series of these holes for my runtime tests without any apparent overheating of the tools or the batteries. All of the subcompacts could also drill a 1 1/2-inch hole, but it took me anywhere from 30 seconds to well over a minute to do it, and it's clearly not what they're made for (my 18-volt hammer-drill bores 1 1/2-inch holes with ease in about 15 seconds or less).
All seven subcompacts also had enough power in low gear to sink a #10 by 4-inch Woodex deck screw in Douglas fir without a pilot hole, but that also seemed to be pushing it. They all easily drove #9 by 3-inch Woodex screws.