For this article, I tested ten professional-grade tools from
nine different manufacturers: Bosch, DeWalt, Hilti, Hitachi,
Makita, Metabo, Milwaukee, Panasonic, and Porter-Cable. I chose
to focus on the 14.4-volt tools because they're a reasonable
compromise between the lighter 12-volt and the heavier 18- and
24-volt models. Tradespeople seem to agree, because they buy
more 14.4-volt drill-drivers than any other cordless
tool.
We included three 15.6-volt drills from companies that don't
make 14.4-volt tools. It's reasonable to include them because
they have similar specs and performance; the only difference is
an extra cell in the 15.6-volt battery packs.
The current specs are impressive, but what really counts is
what the tools can do. The Porter-Cable model wasn't available
until recently, but the rest of the tools showed up while I was
doing a major kitchen remodel. Every day I used two or three
different guns. This meant using them for everything from
drilling holes for Romex and plumbing lines to installing
drywall and cabinets. I also put the drills through a
side-by-side test to get an idea of power and run-time.
Power and
Weight
Manufacturers break cordless drill users into two distinct
groups. The people in the first group want as much power as
they can get and don't mind carrying heavier tools to get it.
The people in the second group are willing to sacrifice power
to get a light, maneuverable drill with superior
run-time.
The split makes sense. People who frame, build decks, or work
in subtrades like electrical, plumbing, and hvac drill big
holes and drive lags and oversized fasteners. Only the bigger,
heavier drills have the power to perform those tasks. People
who do finish work like hanging doors or building and
installing cabinets don't need that much power and can be more
productive with a light, compact tool.
Judging by the tools, manufacturers seem to favor the workers
who want more power. The last time this magazine looked at
14.4-volt drills was in 1999, when the most powerful tool
produced 330 inch-pounds of torque in the low speed setting.
This time around, the top performer put out 484 inch-pounds.
But that increase in power comes at the cost of some added
weight. The current crop averages 5 pounds apiece, which is a
half pound heavier than the models we tested in 1999. And the
heaviest 14.4-volt tools outweigh some 18- and 24-volt
models.
Power-to-weight ratio. Ask a
tradesperson for an opinion about a power tool and you're
likely to hear how powerful it is for its weight. Most of us
want as much power as we can get for the weight we carry. It's
easy to feel the difference between the most powerful and the
least powerful drills, but it's harder to judge power in
relation to weight. I calculated power-to-weight ratios by
dividing each tool's torque rating by its weight. That allowed
me to compare drills on the basis of inch-pounds of torque per
pound of weight. I used the manufacturer's torque specs but
weighed the tools myself.
The Metabo and Bosch Brute have the highest torque ratings of
the tools I tested. They also have the highest power-to-weight
ratios. The Milwaukee drill is nearly as powerful but has a
lower power-to-weight ratio because it's heavier. I wouldn't
buy a drill just because it had a high power-to-weight ratio.
But if I had to choose between tools with similar features and
one had 10 more inch-pounds of torque per pound, that's the
drill I'd get.
Run-Time
Run-time is the amount of work you can do on a single charge.
More is better, but you have enough if you can recharge a spare
faster than you can drain the battery that's in the tool.
Otherwise, you'll have to stop working when you run out of
juice. Most chargers take 50 or 60 minutes to do the job, but
it takes longer if the battery is hot.
Run-time is a function of the amount of energy the battery
contains and how hard you work the drill. High-torque
applications and continuous use drain batteries faster than
light-duty work and intermittent use.
Testing run-time. To test
run-time, I counted the number of holes each drill could make
through a 4x4 at low speed with a 3/4-inch auger (see Figure
1). The test was somewhat skewed in favor of the more powerful
tools because they're designed for high-torque applications. It
would have been fairer to also test the tools by driving small
drywall screws, but with today's batteries I'd be in the
hospital after driving that many fasteners.
Figure 1.Drill run-time was tested by drilling
holes through a 4x4 at low speed with a 3/4-inch auger bit. The
number of holes each drill was able to bore on a single fully
charged battery is shown.
What I learned was pretty much in line with the torque specs.
Tools rated at or above 400 inch-pounds in low-speed mode had
no trouble driving the auger bit. They didn't slow down or
exhibit any noticeable strain. The rest of the drills drove the
bit, but I could hear and feel that they had a hard time doing
it.
In general, the higher the watt-hour rating, the more holes
the drill could make. The Panasonic and Hilti have the highest
battery capacities and bored the most holes.
Clutch
Most cordless drills have 16 to 21 clutch settings. But the
actual number is less important than the amount of torque at
the highest and lowest settings. Ideally, the lowest should be
low enough for fine work and the highest high enough to drive
big fasteners.
Most 14.4-volt drills are overkill for light-duty work. But if
the tool can handle such tasks, you can get by with a single
drill. I use low clutch settings to install electrical fixtures
and to install door and cabinet hardware. The ultimate test is
to use the drill to install plastic cover plates. The tool
passes if it does the job without cracking plates or stripping
screws. Seven out of ten drills passed this test. The Bosch
Brute and the Hilti both stripped screws and broke plates. The
low setting on the DeWalt was off the scale, high enough to
sink drywall screws in oak.
The upper clutch settings are less important than the low ones
because most workers drive all but the smallest fasteners in
drill mode. That said, it's a plus if the high settings have
enough torque to drive fasteners like the long screws used to
install sliders and exterior door hinges. I tested that by
sinking 2 1/2-inch #8 drywall screws into a 4x4. All of the
tools had high enough settings to do it without clutching
out.
Speeds and
Gears
My first cordless drill was a state-of-the-art tool with a
single speed range that topped out at 600 rpm. Compared with
the tools you can get now, that drill was downright pathetic.
Most of the tools I tested have two speed ranges and max out at
around 1,400 rpm. Unlike early models, these tools have enough
speed to drill metal and drive self-drilling screws. Low range
usually tops out at 400 rpm and is intended for high-torque
applications. The DeWalt model is unusual in that it has a
third range that tops out at 1,800 rpm (Figure 2).
Figure 2.Most drill-drivers have two speed ranges;
the DeWalt has three.
Some drills have all-metal gears, but most have a combination
of metal and plastic. It's reasonable to think that tools with
all-metal gears should be more durable than tools that use a
combination of materials, but that isn't so. Different gears
are subject to varying amounts of stress, so there are places
where it's okay to use plastic. The main reason companies
choose plastic is not to save money but to lessen the weight of
the tool.
Chucks
Bosch's compact drill has a 3/8-inch chuck; all the others
have 1/2-inch chucks. Most of the tools have a single-sleeve
chuck equipped with a self-locking mechanism. The mechanism
automatically locks the motor shaft when you twist the chuck by
hand. That makes it easier to change bits because you can do it
one handed without changing clutch settings. The Hitachi and
the Makita have two-piece chucks that aren't
self-locking.
Most of the chucks are made from a combination of plastic and
steel, but the chucks on the Milwaukee and the Porter-Cable are
all steel. Those manufacturers used only steel to increase
durability, but it's one reason their drills are the two
heaviest I tested.
Grip
The first thing you notice when you use a new drill is how it
feels in your hand. This includes everything from weight and
balance to the shape and texture of the grip. All of the drill-
drivers except the Metabo have rubberized grips. The rubber
provides a little padding but is really there to reduce user
fatigue. It does that by making the tool easier to grip, even
when your hands are wet.
All of the tools have a T-handle configuration, so they all
feel balanced. The grips vary in shape, but they're all
comfortable. That said, you may want to avoid the Metabo and
Bosch Brute if you have small hands because it's a stretch to
reach the reversing switch with your thumb.
The Porter-Cable tool has a unique adjustable grip. It comes
with interchangeable inserts that can be installed on the back
of the grip. The thicker the insert, the bigger the grip
(Figure 3).
Figure 3.Porter-Cable's Grip-to-Fit comes with
interchangeable inserts, so you can customize the size of the
grip.
Size and
Configuration
We all have to work in cramped quarters occasionally. But if
you do finish work like building or installing cabinets, you
get into tight spots all the time. Two tools that stand out for
that kind of work are the Panasonic and the Bosch Compact
Tough. Both are a lot more compact than the other drills.
Excluding the jaws, they measure about 8 1/4 inches front to
back. By way of comparison, the longest drills, the Milwaukee,
Porter-Cable, and DeWalt, are just over 10 inches long. This
may not sound like much, but if you regularly work in tight
quarters, an extra inch or two can mean the difference between
doing the job with a drill and doing it by hand.
Special
Features
All the drills I tested come with two batteries, a case, and a
charger. But some have features that I hadn't seen
before.
With most drills, you turn the clutch collar to go from drill
to drive mode. But with Makita's tool, you go from drive to
drive by moving a lever on top of the gear housing (Figure
4).
Figure 4.The Makita drill features a convenient
top-mounted lever that allows switching from driver to drill
and back without losing the dialed-in clutch
setting.
That allows you to switch back and forth between drilling and
driving without losing your clutch setting. Inside most
cordless tools is a metal housing, a can that contains the
entire motor. But if you open the Makita, you'll see a
two-piece motor that resembles what you'd find inside a corded
tool. According to the manufacturer, this allowed the designers
to make the motor smaller, more efficient, faster to cool, and
easier to service (Figure 5).
Figure 5.Most cordless drills, like the Hitachi
(left), have can-style motors. The field, armature, fan, and
brushes are encased in a metal housing and are typically
serviced or replaced as a unit. The Makita drill (right) is
built around an unusual two-piece motor equipped with a cooling
fan.
The Metabo drill has a unique hidden feature. Flip a tiny
switch on the back of the motor housing, and the tool goes into
pulse mode, which causes the motor to pulse on and off when you
squeeze the trigger. According to the manufacturer, that makes
it easier to start holes in smooth materials like metal. It's
also supposed to make driving and removing fasteners easier,
especially if the head is damaged. I didn't notice any
difference drilling metal, but the pulse action did make it
easier to ease out damaged screws. I had never given it any
thought, but I've been doing this manually for years by
squeezing and releasing the trigger.
The Makita, Milwaukee, and Bosch Brute have externally
replaceable brushes. This feature is a plus for tools that get
extremely heavy use, but I can't imagine it making much of a
difference on a cordless drill. You'll probably wear out the
batteries before you go through a pair of brushes. And at that
point, the tool will be so out of date that you'll want to
upgrade.
Favorites
My personal favorite is the Panasonic because it does
everything well. It's in the middle of the pack in terms of
power and weight. But it's extremely compact and has better
run-time than any other drill tested. I also like the Bosch
Compact because it's extremely small and light for a 14.4-volt
tool. As for the big drills, I like the Bosch Brute and the
Metabo because they have the most power and superior
power-to-weight ratios. I also like the Milwaukee because it's
comparable in power to the Bosch and Metabo but is easier to
grip if you have smaller hands.
Battery Basics
With cordless tools, power comes at the expense
of run-time. Increase power beyond a certain point,
and the tool drains batteries so quickly that it's
no longer practical to use. Luckily, batteries keep
getting better and better.
Most of us think of batteries in terms of voltage.
But all voltage tells you is how many cells are in
the battery. A 14.4-volt battery contains 12 cells,
and a 15.6-volt unit contains 13. The amount of
energy that individual cells can hold is determined
by their amp-hour rating. Ten years back,
state-of-the-art was 1.0 amp-hour cells. Right now,
state-of- the-art is 3.5 amp-hours, and I'd be
surprised if it doesn't go higher soon. Watt-hours and storage
capacity. The amount of energy contained in
a battery is measured in watt-hours. You can
calculate the watt-hour rating of a battery by
multiplying its voltage by the amp-hour rating of
its cells. For example, a 14.4-volt tool with 2.0
amp-hour cells is rated at 28.8 watt-hours (14.4
volts x 2.0 amp-hours). A battery with a
50-watt-hour rating contains twice as much energy
as one with a 25-watt-hour rating. NiCad vs. NiMH.
Most cordless-tool batteries contain nickel-cadmium
(NiCad) cells, but a small percentage use
nickel-metal-hydride (NiMH) cells. NiCads have been
around forever, but NiMH batteries have been in
cordless tools for less than five years. NiMH cells
have higher amp-hour ratings than NiCads.
But the jury's out on whether one type is better
than the other. NiMH cells do hold more energy, but
they're a lot more expensive and can be charged
fewer times than NiCads. Just how many charging
cycles a battery can undergo is open to debate.
Depending on whom you talk to, NiCads can be
charged 750 to 2,000 times before wearing out.
Someone I know at one of the manufacturers said
NiCads are good for about 1,200 cycles. His company
doesn't use NiMH cells because it believes they're
only good for 300 to 500 cycles. But according to
Panasonic, which is the only company that makes
battery cells as well as tools, NiMH cells are good
for 1,200 cycles. And the companies that use NiMH
batteries claim you get more run-time over the life
of the batteries because they can go a lot longer
between charges.
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