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Festool C12 EC-TEC Review Manual page 4

Technical review
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Another feature of the C12 gearbox is the integral
shaft-lock to assist in bit changing. The motor can
rotate the drill chuck, but the drill chuck cannot
Conclusion
I'm not big on drawing conclusions for others to
follow. I am more comfortable writing fact-based
information. So instead, I will use this space to
provide some of the opinion-based information I
came across during my examination. It might be
a hodge-podge of ideas, but I guess that's what
opinions are supposed to be.
I first saw a cutaway model of the C12 at the
AWFS trade show in Las Vegas this summer (see
the cutaway picture on page 2). I was so
fascinated with the idea that a 3-phase motor was
being used in a battery operated tool that I
volunteered to write this technical review and
give it to Festool without taking a fee for my
work.
With technology this cutting-edge, I knew there
would be a lot of people that were not yet
familiar with it (including myself). Besides, I was
dying for a chance to tear this drill apart to see
how it worked (I am a card-carrying member of
tool-junkies anonymous).
While it wasn't very scientific, one of the first
things I did when the drill arrived was to try to
drive a 4-inch screw into a block of wood; except
I wanted to see what would happen at ultra-
ultra-low speed—about 1 revolution per second.
I carefully held the trigger in a fixed position so
the bit was spinning at a constant speed, and
then started the screw into the wood. I can't even
begin to tell you just how blown away I was
when the drill kept plodding along until the
entire 4-inch screw was sunk into the wood. I
tried the same thing with one of my other drills,
and it stalled after just 1 inch.
Oh by the way, I wasn't doing this in low-gear
like you would expect. The drill was in high-
gear! The motor appears to deliver a constant
torque at any speed or load. However, without
seeing the schematic of the motor's electronic
rotate the motor. With the shaft-lock, you can
tighten the chuck as hard as you want, and the
gearbox will hold fast.
controller I cannot state this as fact, so I am
leaving it as just my opinion.
My excitement just kept escalating from there on.
So the next thing I did was build a dynamometer
so I could compare the power of this 12-volt drill
against several 14 and 18-volt drills I bought at
my local home center.
Unfortunately, when the three most popular
drills on the market (names withheld) started
smoking under my dynamometer's load, I
decided it would not be wise to publish this data,
lest I wanted a lawsuit. However, I found it very
curious that the only drills with torque curves
higher than the C12 were also the ones that
allowed their motors to self-destruct.
I could have legitimately published the rest of
the data, and throw out outlying data because
the drills destroyed themselves to achieve their
results. Instead, I decided to throw out the entire
test, because trying to explain the outliers might
have sounded like I was playing games with the
data; and I refuse to publish anything that
sounds misleading.
Finally, there are a lot of intangibles about this
drill that don't fit neatly into a technical review.
Here are some other quick observations:
The motor is extremely smooth and quiet;
noticeably so over other cordless drills.
The drill is perfectly balanced, with the center
of balance right over the trigger—you can
balance the drill on your index finger.
Even with the largest optional batteries, the
drill is still very light.
Changing batteries is very easy because the
batteries slide in from the front, and the latches
don't need to support the weight of the battery
like most other drills.
4

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