Makita HR2420 Manuel D'instructions page 6

Depth gauge (Fig. 5)
The depth gauge is convenient for drilling holes of
uniform depth. Insert the depth gauge into the hole in
the grip base. Adjust the depth gauge to the desired
depth and then tighten the clamp screw to secure the
depth gauge.
NOTE:
The depth gauge cannot be used at the position
where the depth gauge strikes against the gear
housing.
Switch action (Fig. 6)
CAUTION:
Before plugging in the machine, always check to see
that the switch trigger actuates properly and returns to
the ''OFF'' position when released.
To start the machine, simply pull the trigger. Machine
speed is increased by increasing pressure on the
trigger. Release the trigger to stop.
Reversing switch action (Fig. 6)
CAUTION:
• Always check the direction of rotation before opera-
tion.
• Use the reversing switch only after the machine
comes to a complete stop. Changing the direction of
rotation before the machine stops may damage the
machine.
• Do not pull the switch trigger when the reversing
switch lever is in the neutral position. If you pull the
trigger forcibly, the switch may be damaged.
This machine has a reversing switch to change the
direction of rotation. Move the lever to the
tion (A position) for clockwise rotation or the
tion (B position) for counterclockwise rotation.
Selecting action mode (Fig. 7)
This machine employs an action mode changing
knob. Select one of the two modes suitable for your
work needs by using this knob. For rotation only, turn
the knob so that the arrow on the knob points toward
the symbol on the machine body. For rotation
with hammering, turn the knob so that the arrow on
the knob points toward the
machine body.
CAUTION:
Always set the knob fully to your desired mode
symbol. If you operate the machine with the knob
positioned half-way between the mode symbols, the
machine may be damaged.
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Torque limiter
The torque limiter will actuate when a certain torque
level is reached. The motor will disengage from the
output shaft. When this happens, the bit will stop
turning.
CAUTION:
• As soon as the torque limiter actuates, switch off the
machine immediately. This will help prevent prema-
ture wear of the machine.
• Hole saws, core bits, diamond core bits, etc. cannot
be used with this machine. They tend to pinch or
catch easily in the hole. This will cause the torque
limiter to actuate too frequently.
Hammer drilling operation
Position the bit at the desired location for the hole,
then pull the trigger.
Do not force the machine. Light pressure gives best
results. Keep the machine in position and prevent it
from slipping away from the hole.
Do not apply more pressure when the hole becomes
clogged with chips or particles. Instead, run the
machine at an idle, then remove the bit partially from
the hole. By repeating this several times, the hole will
be cleaned out and normal drilling may be resumed.
CAUTION:
There is a tremendous and sudden twisting force
exerted on the machine/bit at the time of hole break-
through, when the hole becomes clogged with chips
and particles, or when striking reinforcing rods
embedded in the concrete. Always use the side grip
(auxiliary handle) and firmly hold the machine by both
side grip and switch handle during operations. Failure
posi-
to do so may result in the loss of control of the
posi-
machine and potentially severe injury.
Bit grease
Coat the bit shank head beforehand with a small
amount of bit grease (about 0.5 – 1 g).
This chuck lubrication assures smooth action and
longer service life.
Blow-out bulb (Fig. 8)
Use the blow-out bulb to clean out the hole.
symbol on the
Dust cup (Fig. 9)
Use the dust cup to prevent dust from falling over the
machine and on yourself when performing overhead
drilling operations. Attach the dust cup to the bit as
shown in Fig. 9. The dust cup can be attached to the
bit up to 14.5 mm in diameter.