Operation - Makita HR3851 Instruction Manual

Installing or removing the bit
Press in the tool retainer and turn it until the red dots on
the tool retainer and the tool holder are aligned. Release
the tool retainer.
Insert the bit into the tool holder as far as it will go. Press
in the tool retainer and turn it a full 180 degrees. Then
release it to secure the bit.
1
3
2
To remove the bit, follow the installation procedure in
reverse.
Depth gauge
2
The depth gauge is convenient for drilling holes of uni-
form depth. Insert the depth gauge into the hole in the
grip base. Adjust the depth gauge to the desired depth
003149
003153
1. Red dot
1
(Tool holder)
2. Red dot
2
(Tool retainer)
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1. Tool retainer
2. Turn 180°
3. Press in
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1. Clamp screw
1 2. Depth gauge
3. Grip base
3
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 tool
body.

OPERATION

Hammer drilling operation
Set the change lever to the
Position the bit at the desired location for the hole, then
pull the switch trigger. Do not force the tool. Light pres-
sure gives best results. Keep the tool in position and pre-
vent 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 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
control of the tool and potentially severe injury.
Blow-out bulb (optional accessory)
After drilling the hole, use the blow-out bulb to clean the
dust out of the hole.
5
003199
symbol.
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1. Blow-out bulb
1