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Using Rotary Percussion Core Bits (Fig. 8-11)
Core bits are useful for drilling large holes for conduit and pipe.
MILWAUKEE Heavy-Duty Core Bits have heat-treated steel bodies with
durable carbide tips. These core bits are specially designed for fast, accurate
drilling with combined hammering and rotary action.
1. Clean and lubricate the threads on the adapter and core bit to make
later removal easier. Screw the threaded end of the adapter into the
rear of the core bit.
2. Push the guide plate onto the pointed end of the center pin. Insert the
center pin and guide plate assembly into the core bit. Be sure the small
end of the center pin is securely placed into the hole in the center of
the core bit (Fig. 8).
Starting and Stopping the Tool
1. To start the tool, pull trigger.
2. To stop the tool, release trigger.
If this tool is stored for a long period of time or at cold temperatures,
it may not hammer initially because the lubrication has become stiff.
To warm up the tool:
1. Insert and lock a bit or chisel into the tool.
2. Turn the tool on, applying force to the bit or chisel against a concrete
or wood surface.
3. Turn the tool on and off every few seconds. In a short time, the tool will
start hammering. The colder the tool is, the longer it will take to warm
Operator Force (Fig. 7)
These rotary hammers feature the Vibration Isolation System to pro-
vide the operator with comfort without sacrificing power or perfor-
mance. The motor is suspended independently from the switch handle.
Insulating elements absorb up to 50% of the vibration when hammering
Ideal operator force compresses the bellows slightly and allows the tool to
work aggressively while the handle remains steady.
Excessive force compresses the bellows signiﬁ cantly and reduces vibration
dampening. Users will be able to feel the difference and should adjust the
force to the handle accordingly (Fig. 7).
ideal applied force
excessive applied force
The side handle works in a similar fashion, where moderate operator force
dampens vibration and excessive force reduces this effect.
Hammering or Hammering with Rotation
Position the tool, grasp the handles ﬁ rmly and pull the trigger.
Always hold the tool securely using both handles and maintain control. Use
only enough pressure to hold the tool in place and prevent the tip of the bit
from wandering. This tool has been designed to achieve top performance
with only moderate pressure. Let the tool do the work.
When drilling deep holes occasionally pull the bit partially out of the hole
while the tool is running to help clear dust.
NOTE: Do not use water to settle the dust since it will clog the bit ﬂ utes
and tend to make the bit bind in the hole. If the bit should bind, a built-in,
non-adjustable slip clutch prevents the bit from turning. If this occurs, stop
the tool, free the bit and begin again.
3. Insert the adapter into the nose of the tool as described in “Install-
ing Bits”. Set the stop rotation knob to the hammering-with-rotation
4. Press the center pin ﬁ rmly against your center mark, hold the tool ﬁ rmly
and pull the trigger (Fig. 9).
NOTE: If a center pin and guide plate are not available, use a template
or notched board to start the hole (Fig. 10).
5. After drilling to about the depth of the core bit teeth, remove the center
pin and guide plate from the core bit. Resume drilling.
Applying greater pressure does not increase the
tool's effectiveness. If the applied working pres-
sure is too high, the shock absorber will be pushed
together making the vibrations to the handle no-