Maintenance - DeWalt D21716 Original Instructions Manual

E N G L I S H
WARNING: To reduce the risk of serious
personal injury, ALWAYS hold securely in
anticipation of a sudden reaction.
Proper hand position requires one hand on the side
handle (6), with the other hand on the main handle
(11).
Switching On and Off (fi g. A)
• To run the tool, press the variable speed switch (1).
The pressure exerted on the variable speed switch
determines the tool speed.
• If necessary, press the lock-on button (2) for
continuous operation and release the switch.
The lock-on button works only in full speed,
forward rotation.
• To stop the tool, release the switch.
• To stop the tool in continuous operation, press
the switch briefl y and release it. Always switch
off the tool when work is fi nished and before
unplugging.
Screwdriving
• Select forward or reverse rotation.
Percussion Drilling (fi g. A)
• Select the percussion mode.
• Press the switch (1).
Rotary Drilling (fi g. A)
• Select the rotary drilling mode.
• Proceed as described for percussion drilling.
Drilling
WARNING: To reduce the risk
of serious personal injury, turn
tool off and disconnect tool from
power source before making any
adjustments or removing/installing
attachments or accessories.
WARNING: To reduce the risk of
personal injury, ALWAYS ensure
workpiece is anchored or clamped firmly.
If drilling thin material, use a wood "back-
up" block to prevent damage to the
material.
1. Use sharp drill bits only. For WOOD, use the
low speed setting and twist drill bits, spade bits,
power auger bits, or hole saws. For METAL, use
the low speed setting and steel twist drill bits or
hole saws.
26
2. Always apply pressure in a straight line with the
bit. Use enough pressure to keep drill biting, but
do not push hard enough to stall the motor or
deflect the bit.
3. Hold tool firmly with both hands to control the
twisting action of the drill.
CAUTION: Drill may stall if overloaded
causing a sudden twist. Always expect
the stall. Grip the drill firmly to control the
twisting action and avoid injury.
4. IF DRILL STALLS, it is usually because it is
being overloaded or improperly used. RELEASE
TRIGGER IMMEDIATELY, remove drill bit
from work, and determine cause of stalling. DO
NOT CLICK TRIGGER ON AND OFF IN AN
ATTEMPT TO START A STALLED DRILL —
THIS CAN DAMAGE THE DRILL.
5. To minimize stalling or breaking through the
material, reduce pressure on drill and ease the bit
through the last fractional part of the hole.
6. Keep the motor running when pulling the bit
back out of a drilled hole. This will help prevent
jamming.
7. With variable speed drills there is no need to
center punch the point to be drilled. Use a
slow speed to start the hole and accelerate by
squeezing the trigger harder when the hole is
deep enough to drill without the bit skipping out.
DRILLING IN METAL
Start drilling with slow speed and increase to full
power while applying firm pressure on the tool. A
smooth even flow of metal chips indicates the proper
drilling rate. Use a cutting lubricant when drilling
metals. The exceptions are cast iron and brass which
should be drilled dry.
NOTE: Large [5/16" (8 mm) to 1/2" (13 mm)] holes in
steel can be made easier if a pilot hole [5/32"
(4 mm) to 3/16" (5 mm)] is drilled first.
DRILLING IN WOOD
Start drilling with slow speed and increase to full
power while applying firm pressure on the tool. Holes
in wood can be made with the same twist drills used
for metal. These bits may overheat unless pulled out
frequently to clear chips from the flutes. Work that is
apt to splinter should be backed up with a block of
wood.

MAINTENANCE

Your D WALT power tool has been designed to
E
operate over a long period of time with a minimum