Maintenance - Makita 8406C Instruction Manual

withdrawing the tool.
Fig.15
CAUTION:
Make sure that water is running constantly from the
•
hole during operation. If the water flow becomes
inadequate, withdraw the tool slightly and press it
again. Water should run freely. But if the problem
persists, unplug the tool and replenish the bit with
water immediately.
When resuming operation, do not turn the tool on
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until the bit end reaches the deepest portion of the
hole.
Remove core material from the bit through the front
opening.
Fig.16
CAUTION:
When removing the core material from the bit, do
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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.17
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.18
CAUTION:
Be careful not to damage the diamond core bit or
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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.19
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.20
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.21
Reduce your pressure on the tool if the core bit contacts
reinforcing bars or foreign matter in the concrete and
when the core bit begins to break through the concrete.
Fig.22
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.23
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 operation
(with a tungsten-carbide tipped bit)
When drilling in concrete, granite, tile, etc. with a
tungsten-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.
Drilling operation
(with a conventional drill bit)
When drilling in wood, metal or plastic materials, move
the action mode changing lever to the position of
symbol to use "rotation only" action.
Drilling in wood
When drilling in wood, the 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.
Drilling in metal
To prevent the bit from slipping when starting a hole,
make an indentation with a center-punch and hammer 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. 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 force exerted on the tool/bit
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at the time of hole break through. Hold the tool
firmly and exert care when the bit begins to break
through the workpiece.
Always secure small workpieces in a vise or similar
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hold-down device.

MAINTENANCE

CAUTION:
Always be sure that the tool is switched off and
•
unplugged before attempting to perform inspection
or maintenance.
Never use gasoline, benzine, thinner, alcohol or the
•
like. Discoloration, deformation or cracks may
result.
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