Operation; Maintenance - Makita DHR241 Instruction Manual

Bit angle (when chipping, scaling or
demolishing)
► Fig.12: 1. O symbol 2. Action mode changing knob
The bit can be secured at the desired angle. To change the bit
angle, depress the lock button and rotate the action mode chang-
ing knob to the O symbol. Turn the bit to the desired angle.
Depress the lock button and rotate the action mode
changing knob to the
the bit is securely held in place by turning it slightly.
► Fig.13
Depth gauge
► Fig.14: 1. Depth gauge
The depth gauge is convenient for drilling holes of
uniform depth. Loosen the side grip and insert the depth
gauge into the hole in the side grip. Adjust the depth
gauge to the desired depth and tighten the side grip.
NOTE:
• The depth gauge cannot be used at the position
where the depth gauge strikes against the gear
housing.
Dust cup
► Fig.15: 1. Dust cup
Use the dust cup to prevent dust from falling over the tool and
on yourself when performing overhead drilling operations.
Attach the dust cup to the bit as shown in the figure. The size
of bits which the dust cup can be attached to is as follows.
Dust cup 5
Dust cup 9

OPERATION

Hammer drilling operation
► Fig.16
Set the action mode changing knob to the
Position the bit at the desired location for the hole, then
pull the switch trigger.
Do not force the tool. Light pressure gives best results. Keep the
tool 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 tool 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 tool/bit at the time of hole
break-through, when the hole becomes clogged
with chips and particles, or when striking rein-
forcing rods embedded in the concrete. Always
use the side grip (auxiliary handle) and firmly
hold the tool by both side grip and switch handle
during operations. Failure to do so may result
in the loss of control of the tool and potentially
severe injury.
symbol. Then make sure that
Bit diameter
6 mm - 14.5 mm
12 mm - 16 mm
symbol.
NOTE: Eccentricity in the bit rotation may occur while
operating the tool with no load. The tool automatically
centers itself during operation. This does not affect
the drilling precision.
Blow-out bulb (optional accessory)
► Fig.17: 1. Blow-out bulb
After drilling the hole, use the blow-out bulb to clean the
dust out of the hole.
Chipping/Scaling/Demolition
► Fig.18
Set the action mode changing knob to the
Hold the tool firmly with both hands. Turn the tool on
and apply slight pressure on the tool so that the tool will
not bounce around, uncontrolled. Pressing very hard on
the tool will not increase the efficiency.
Drilling in wood or metal
► Fig.19: 1. Chuck adapter 2. Keyless drill chuck
► Fig.20: 1. Sleeve 2. Ring
Use the optional drill chuck assembly. When installing it,
refer to "Installing or removing the bit" described on the
previous page.
Set the action mode changing knob so that the pointer
points to the symbol.
CAUTION:
• Never use "rotation with hammering" when the
drill chuck assembly is installed on the tool. The
drill chuck assembly may be damaged. Also, the
drill chuck will come off when reversing the tool.
• Pressing excessively on the tool will not speed
up the drilling. In fact, this excessive pressure
will only serve to damage the tip of your bit,
decrease the tool performance and shorten the
service life of the tool.
• There is a tremendous twisting force exerted
on the tool/bit at the time of hole breakthrough.
Hold the tool firmly and exert care when the bit
begins to break through the workpiece.
• A stuck bit can be removed simply by setting
the reversing switch to reverse rotation in order
to back out. However, the tool may back out
abruptly if you do not hold it firmly.
• Always secure small workpieces in a vise or
similar hold-down device.

MAINTENANCE

CAUTION:
• Always be sure that the tool is switched off and
the battery cartridge is removed before attempt-
ing to perform inspection or maintenance.
• Never use gasoline, benzine, thinner, alcohol
or the like. Discoloration, deformation or cracks
may result.
8 ENGLISH
symbol.