Impact driver 101—the basics
A few years ago,
cordless
impact drivers
were a specialty tool,
rare on job sites and
scarce on store
shelves. Today,
you'll see several
models at any tool
retailer and hear their
machine-gun chatter
wherever there's construction.
When a tool gains popularity that fast,
you have to wonder what's going on.
And, more important,
what you're missing.
To sort out the pros and cons of impact drivers, we put them in the hands of our staff editors
and field editors, who are pros on the job and DIY guys at home. Here's what we learned:
Tip 1: It's all about torque
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Drive long screws
You can drive long screws because impact drivers generate a lot of torque.
Impact drivers have one
overwhelming advantage
over standard drills and
drivers: enormous torque.
Basically, that means you
can drive a big screw (or
bore a big hole) with a
small driver. In this photo,
we sank 3/8 x 10-in. self-drilling
lag screws into cedar
lumber. No pilot holes, no
cheating.
Tip 2: Not just for driving screws
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Bore big holes
Impact drivers can easily handle big bits for boring large holes.
Impact drivers make great drills. With small bits (up to 1/4 in.
or so), they act like a drill—but at nearly twice the rpm of most
cordless drills. With bigger bits, they kick into high-torque
impact mode so you can bore a big hole with a small driver.
Tip 3: One-handed driving
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Easier driving
The drill bit stays engaged, allowing for easier one-handed driving.
With a standard driver, you
have to get your weight
behind the screw and push
hard. Otherwise, the bit will
“cam out” and chew up the
screw head. Not so with an
impact driver. The hammer
mechanism that produces
torque also creates some forward
pressure. That means
you don't have to push so
hard to avoid cam-out. Great
for one-handed, stretch-and-drive
situations.
Tip 4: The only driver you'll ever need?
Maybe. An impact driver will
handle just about any job,
and some of our testers have
already retired their old drivers.
But when high torque
isn't needed, most of us like
to avoid the noise and reach
for standard cordless drills or
drivers instead.
Tip 5: Loud, really loud
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Sound protection
Protect your hearing. Impact drivers are loud.
An impact driver can bring
a heavy-metal drummer
to tears. Wear muffs or
earplugs—or get fitted for a
hearing aid. Your call.
Tip 6: It's not a hammer drill
An impact driver works kind
of like a hammer drill and
sounds a lot like one. But
it's no substitute for a hammer
drill. An impact driver's
innards are engineered to
generate torque, not powerful
forward blows.
Tip 7: Use hex shafts only
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Hex shaft drill bit
The driver chuck only accepts hex shaft bits.
The chuck on an impact driver
makes for quick changes; just
slide the collar forward and
slip in the bit. But you'll have
to buy hex-shaft drill bits.
Regular bits won't work.
Tip 8: Small and smaller
Generally, there's a big torque difference between 12- and
18-volt models. But some of the 18-volt sluggers are amazingly
compact—not much bigger than their 12-volt cousins.
Big torque in a compact tool—that's why most of our testers
favored the 18-volt versions.
Driver Size Comparison
The 18-volt driver is only slight larger than the 12-volt driver. Both are compact.
Tip 9: Easy to handle
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Easy on the arm
Despite the torque, an impact driver is easy to handle.
You might think that extreme
torque puts extreme strain on
your arm. Nope. For reasons
Isaac Newton could explain,
an impact driver actually
generates less wrist twist
than a standard driver. Don't
be fooled by the macho-man
feeling you get when you
effortlessly sink a big screw.
A little princess can do the
same thing.
Tip 10: Consider a combo kit
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Combo kit
You save when you buy a combo kit.
For a few bucks more than an impact driver alone, you can
add a driver, a drill or a hammer drill to your tool collection.
This driver/impact driver twosome cost us just $25 more than
either tool sold separately. We couldn't resist.
Tip 11: Prepare for impact
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Hex-shaft accessories
Most of the items in an accessory kit will come in handy.
Pick up a set of hex-shaft
accessories for about $25
(drill bits, driver bits, socket
adapters). You'll want most
of that stuff sooner or later,
and buying a kit will save you
a few bucks. Check the label
and get a set that's tough
enough for impact-driver duty.
Tip 12: They all look alike outside, but . . .
The difference is how they transfer torque from the motor to the chuck. On a standard drill or
driver, the motor and chuck are locked together through gears; as the workload increases, the
motor strains. An impact driver
behaves the same under
light loads. But when resistance
increases, a clutch-like
mechanism disengages the
motor from the chuck for a split
second. The motor continues to turn
and builds momentum. Then the
clutch re-engages with a slam, transferring
momentum to the chuck. All
of this happens about 50 times per
second, and the result is three or
four times as much torque from a
similar-size tool.
Impact driver, torque: 930 in.-lbs.
Standard driver, torque: 265 in.-lbs.
Impact Driver/Standard Driver Comparison
These two tools may look alike on the outside, but they operate differently.
Tip 13: Good for gearheads, too
They don't have nearly
the torque of big impact
wrenches, but cordless
impact drivers can be a
time-saver when you tinker
with engines. They're perfect
for small engines, where less
torque is usually enough. For
automotive work, consider
an “angle” version, such as
the Craftsman shown later. Hitachi,
Makita, Ridgid and others
also make angle impact
drivers.
Impact driver round-up and test results
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Makita BTD141
Cost: $280
Torque: 1,330 in.-lbs.
Weight: 3.4 lbs.
Battery: 18V lithium (2)
A great tool with
ample power and
a compact,
comfortable
design.
2 of 6
Hitachi WH14DAF2
Cost: $145
Torque: 1060
Weight: 3.8 lbs.
Battery: 14.4V NiCad (2)
The work light is in the belt hook and operates by
push button. Some testers liked it; most didn't.
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Ridgid R86031
Cost: $170
Torque: 1,440 in.-lbs.
Weight: 3.5 lbs.
Battery: 18V lithium (1)
A pro-grade performer, and the lifetime battery
warranty is a huge bonus.
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Milwaukee 2450-22
Cost: $120
Torque: 850 in.-lbs.
Weight: 2.3 lbs.
Battery: 12V lithium (2)
Well-made and pro grade with
a tempting price tag.
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Makita TD090DW
Cost: $120
Torque: 800 in.-lbs.
Weight: 2 lbs.
Battery: 10.8V lithium (2)
Just 10.8 volts, but as much torque as some
12-volt models. Very light and comfortable, too.
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Rockwell RK2515K2
Cost: $200
Torque: 800 in.-lbs.
Weight: 3 lbs.
Battery: 12V lithium (2)
A lifetime battery warranty and two cool
features: a clutch like the one on standard
drivers, and adjustable impact mode.
It wasn't easy, but after weeks of
testing, retesting and arguing, we
settled on six favorites. The models
shown here are widely available at
home centers and hardware stores.
If you're willing to do some hunting,
you'll find several other models and
manufacturers.
Tip: Watch for falling prices.
Don't be surprised if you find lower
price tags than listed here. We
watched prices during a six-week
period and saw prices drop on one
out of every four models shown here.
The discounts (sometimes sales,
sometimes permanent price cuts)
were in the 10 to 20 percent range.
Impact driver round-up and test results, continued
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Porter-Cable PCL1201DC-2
Cost: $140
Torque: 950 in.-lbs.
Weight: 2.6 lbs.
Battery: 12V lithium (2)
Lots of power and one of only two 12-volt
drivers with a belt hook (the other is the
DeWalt). Battery gauge too.
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Rockwell RK2800K2
Cost: $200
Torque: 1160 in.-lbs.
Weight: 2.9 lbs.
Battery: 18V lithium (2)
Light and
affordable, plus a
lifetime battery
warranty.
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Craftsman 17428
Cost: $110
Torque: 830 in.-lbs.
Weight: 2.1 lbs.
Battery: 12V lithium (1)
A good performer at a good price. Batteries
are interchangeable with other tools in
Craftsman's Nextec line.
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DeWalt DCF826KL
Cost: $260
Torque: 1,330 in.-lbs.
Weight: 3.1 lbs.
Battery: 18V lithium (2)
Most compact and
lightweight of the
18-volt models, but
it has lots of power.
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Drill Master 67028
Cost: $45 (driver, one battery, charger; each sold separately)
Torque: 850 in.-lbs.
Weight: 4.2 lbs.
Battery: 18V NiCad (1)
Unbelievable price: about half the cost of
any other model we tried. Available at
harborfreight.com.
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Craftsman 17562
Cost: $100
Torque: 700 in.-lbs.
Weight: 3 lbs.
Battery: 12V lithium (1)
This is the only “angle” driver
we tested. High torque for
tight spots. The Nextec
battery works with other
tools. Nice price.
Our Over-All Favorite: Milwaukee 2650-22
Cost: $320 (Ouch!)
Torque: 1,400 in.-lbs.
Weight: 3.5 lbs.
Battery: 18V lithium (2)
Of our 10
testers, eight gave
this one the top
rating. In our
lag-screw races,
it consistently
matched or exceeded the others. In
addition to raw power, it has all the features
we loved: a tool-belt hook, a bright
work light and a battery “fuel gauge.”
Bummer: No onboard bit storage.
Dissenting opinion: The DeWalt
DCF826KL is better. It has almost
as much torque, but it's lighter, more
compact and comfortable.
— Gary Wentz, senior editor
Compact Bargain: Hitachi WH10DFL
Cost: $115
Torque: 840 in.-lbs.
Weight: 2.2 lbs.
Battery: 12V lithium (2)
You can find a smaller and lighter
driver, or more torque, or a lower price.
But for a combination of all three of
those traits, you can't beat this light,
powerful, affordable little gem.
Cramp warning: If you have big hands
or wear gloves on the job, the handle
might be too short. Otherwise, it's one
of the most comfortable drivers we
tested.
Big Power in Small Packages
Bosch PS41-2A
Cost: $160
Torque: 930 in.-lbs.
Weight: 2 lbs.
Battery: 12V lithium (2)
Among the
12-volt models
we tried, this one
takes two prizes:
lightest and most
compact. Plus, it's a
runner-up in torque.
Bonus points: Battery fuel gauge!
DeWalt DCF815S2
Cost: $160
Torque: 950 in.-lbs.
Weight: 2.3 lbs.
Battery: 12V lithium (2)
This driver tops
our list for 12-volt
torque. And
although it's taller
than most, it's
lightweight and
comfy.
Dissenting opinion: Torque—it's THE
reason to have an impact driver. So
these 12-volt models just don't make
sense. Get an 18-volt.
— Max Lemberger, field editor
Terrific Torque, Low Prices
Porter-CablePCL180IDK-2
Cost: $170
Torque: 1,600 in.-lbs.
Weight: 3.6 lbs.
Battery: 18V lithium (2)
You can't beat
this combination:
Top-tier torque
at a price that's
about $100 below
most of the competition.
Skepticism: Top torque rating by far, but
in our tests it performed about the same
as other pro-grade 18-volt models.
Ryobi P230
Cost: $100
Torque: 1,200 in.-lbs.
Weight: 4.5 lbs.
Battery: 18V NiCad (2)
Though not as
powerful as
most of the
other 18-volt
models, this
driver has plenty
of torque for
all but the
toughest jobs—and a crazy-low
price tag.
Curmudgeon's note: I wouldn't buy anything with
a NiCad battery. Lithium is the only way to go.
—Travis Larson, senior editor
