Makita 8406C Manuel D'instructions page 8

CAUTION:
When removing the core material from the bit, do not
gouge it out or hit the bit with a screwdriver, etc.
If you have difficulty removing the core material
through the front opening, use the hex wrench to
loosen the screws and remove the holder. Then
remove the sponge and core material through the
rear opening. (Fig. 15)
To install the holder, align the marking on the holder
with that on the bit and tighten the screws securely
with the hex wrench. (Fig. 16)
CAUTION:
Be careful not to damage the diamond core bit or the
O ring on the holder.
2. Drilling with dry type of diamond core bit
First, unplug the tool. Assemble the bit shank, core
bit and center bit. Install the bit assembly in the drill
chuck. (Fig. 17)
Align the center bit with the center of the hole to be
drilled. Turn the tool on and drill in the concrete until
the diamond portion of the core bit has drilled to a
depth of 3 – 5 mm. This forms a pilot groove for you
to follow when you continue drilling. (Fig. 18)
Remove the center bit from the core bit and place
the core bit back into the pilot groove. Drill the hole
while holding the tool squarely against the concrete.
Do not apply excessive pressure to the tool when
drilling. (Fig. 19)
Reduce your pressure on the tool if the core bit con-
tacts reinforcing bars or foreign matter in the con-
crete and when the core bit begins to break through
the concrete. (Fig. 20)
To remove the core material from the core bit, point
the core bit downwards. If the core material does
not fall out of the core bit smoothly, insert a small rod
into a hole in the rear side of the core bit to push the
core material out. (Fig. 21)
CAUTION:
When drilling in "green" concrete or when drilling
downwards, dust may not be extracted through the
hole smoothly. In this case, use a dust collector to
collect the dust easily.
Hammer drilling (with a tungsten-carbide tipped bit)
When drilling in concrete, granite, tile, etc. with a tung-
sten-carbide tipped bit, first use "rotation only" action to
start a hole, then use "rotation with hammering" action to
continue drilling.
Do not apply more pressure when the hole becomes
clogged with chips or particles. Instead, run the tool at
an idle, then remove from the hole. By repeating this
several times, the hole will be cleaned out.
8
Drilling (with a conventional drill bit)
When drilling in wood, metal or plastic materials, use
"rotation only" action.
1. Drilling in wood
When drilling in wood, best results are obtained with
wood drills equipped with a guide screw. The guide
screw makes drilling easier by pulling the bit into the
workpiece.
2. Drilling in metal
To prevent the bit from slipping when starting a hole,
make an indentation with a centerpunch and ham-
mer at the point to be drilled. Place the point of the
bit in the indentation and start drilling.
Use a cutting lubricant when drilling metals. The
exceptions are iron and brass which should be
drilled dry.
CAUTION:
• Pressing excessively on the tool will not speed up the
drilling. If 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 tremendous force exerted on the tool/bit at the
time of hole breakthrogh. Hold the tool firmly and exert
care when the bit begins to break through the work-
piece.
• Always secure small workpieces in a vise or similar
hold-down device.
MAINTENANCE
CAUTION:
Always be sure that the tool is switched off and
unplugged before attempting to perform inspection or
maintenance.
Replacing carbon brushes (Fig. 22)
Remove and check the carbon brushes regularly.
Replace when they wear down to the limit mark. Keep
the carbon brushes clean and free to slip in the holders.
Both carbon brushes should be replaced at the same
time. Use only identical carbon brushes.
Use a screwdriver to remove the brush holder caps.
Take out the worn carbon brushes, insert the new ones
and secure the brush holder caps. (Fig. 23)
To maintain product SAFETY and RELIABILITY, repairs,
any other maintenance or adjustment should be per-
formed by Makita Authorized or Factory Service Centers
always using Makita replacement parts.