8
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
tool immediately. This will help prevent premature wear
of the tool.
• Hole saws cannot be used with this tool. They tend to
pinch or catch easily in the hole. This will cause the
torque limiter to actuate too frequently.
Hammer drilling operation
(Fig. 15)
Set the action mode changing knob to the
H
symbol.
Position the bit at the desired location for the hole, then
pull the 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 tremendous and sudden twisting force exerted
on the tool/bit at the time of hole breakthrough, 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 tool by both side grip and switch handle during
operations. Failure to do so may result in the loss of con-
trol of the tool 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. 16)
Use the blow-out bulb to clean out the hold.
Dust cup (Fig. 17)
Use the dust cup to prevent dust from falling over the tool
and on yourself when performing overhead drilling opera-
tions. Attach the dust cup to the bit as shown in
Fig. 17
.
The size of bits which the dust cup can be attached to is
as follows.
Chipping/Scaling/Demolition (Fig. 18)
Set the action mode changing knob to the
g
symbol.
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
For model HR2450/HR2450F/HR2450X (Fig. 19)
Use the optional drill chuck assembly. When installing it,
refer to “Installing or removing drill bit” described on the
previous page.
For model HR2450T/HR2450FT (Fig. 11)
Use the drill chuck assembly as standard equipment.
When installing it, refer to “Changing the tool holder”
described on the previous page.
Hold the ring and turn the sleeve counterclockwise to
open the chuck jaws. Place the bit in the chuck as far as
it will go. Hold the ring firmly and turn the sleeve clock-
wise to tighten the chuck.
To remove the bit, hold the ring and turn the sleeve coun-
terclockwise.
(Fig. 20)
Set the action mode changing knob to the
m
symbol. You
can drill up to 13 mm diameter in metal and up to 32 mm
diameter in wood.
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 perfor-
mance 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.
Diamond core drilling
When performing diamond core drilling operations,
always set the change lever to the
m
position to use “rota-
tion only” action.
CAUTION:
If performing diamond core drilling operations using
“rotation with hammering” action, the diamond core bit
may be damaged.
MAINTENANCE
CAUTION:
Always be sure that the tool is switched off and
unplugged before carrying out any work on the tool.
To maintain product safety and reliability, repairs, mainte-
nance or adjustment should be carried out by a Makita
Authorized Service Center.
Bit diameter (mm)
Dust cup 5
6 – 14.5
Dust cup 9
12 – 16
