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Husqvarna DR 350 T Operator's Manual page 16

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• Inclining the column
Unscrew the clamping screws .
Incline the columns to the desired angle .
Maximum inclination 30°.
Screw up the clamping screws.
• Check the drill is tightened on the shaft.
• Check that the pressure and the flow
through the central spray are adequate for
lubrication.
Do not run the machine off load
without a water supply (this will
damage the seals on the spray head).
• Select the rotation speed appropriate for
the bore diameter.
• Turn the motor on (avoiding contact with
the material to be drilled).
• Using the wheel, bring the rotating drill
slowly into contact with the material to be
drilled without exerting undue pressure.
Boring the first centimetre is extremely
critical and should be considered as the
centring of the drill (exerting too much
force will displace the drill sideways
causing friction between the drill tube and
the material which will increase as the
depth increases).
• When the drill has been centred, increase
the drilling force to obtain the correct
penetration speed. Insufficient force will
cause the diamond to become polished
and thus lose its cutting ability, whereas
too great a force will dislodge the diamond
and result in excessive wear.
Note :
When cutting through reinforcing, reduce
the force on the drill as the cutting speed
in steel is less than that in concrete.
• If the initial rotation speed is high in
relation to the diameter of the drill, the
rotation speed should be reduced when
cutting through reinforcing.
• The drill wear depends mainly on the
density of the reinforcing being drilled, the
abrasiveness of the concrete, the type of
aggregate, the ratio of the drill diameter to
the diameter of the reinforcing bars and
the motor power used.
• When boring certain porous or cracked
materials or when boring intersecting
holes, all the water spray disappears into
the material and no water will be seen
running out of the bore hole. In this case,
use the maximum water flow to be sure of
cooling and lubricating the drill.
• Always ensure that the water flow is
sufficient so that the slurry remains fluid.
The slurry, and therefore the drill, should
never become warm.
9
End of boring
• When boring is finished, either when the
drill emerges on the other side or the bore
depth is reached (blind bores) :
stop the motor,
keep the water running,
use the wheel to remove the drill,
at the end of travel, turn off the water.
After boring
10
Vertical bore
• Close the hole immediately so that the
core does not fall back into the hole (if the
core is still inside the drill).
Horizontal bore
• Unscrew the drill from the shaft using a
spanner and remove it. Tap the sides of
the drill tube with the wooden shaft of a
hammer until the core comes completely
out.
• Never bang the drill onto a hard surface
or hit it with a metallic implement: this
might dent the tube making it impossible
to remove the core or to use the drill
again, rendering it useless.
• If the core is jammed inside the drill,
break it up using a cold chisel on the end
striking along the length of the drill or
pushing by means of the connecting shaft
(hole saws).
• If the core remains in the hole :
If the bore is finished, remove the
borer.
If the bore needs to be deepened,
remove the drill only to ensure that the
subsequent bore is centred.
• In both cases, insert a wooden or metallic
wedge into the circular hole and force it in
until the core breaks free. Remove the
core from the hole.
• For bores deeper than the length of the
drill, never remove the borer. Having
removed the first core (as above), put the
drill carefully back into the hole, connect
the extension to it and screw the other
end to the motor shaft.
• Continue drilling as described in
paragraph 9.
11
Maintenance
• After each bore, clean the machine to
prevent the slurry drying on the machine.
• Clean and wipe all of the borer.
• Brush and grease :
the motor shaft threads,
the drill, extension and connector
threads.
• This ensures that the machine remains fully
operational, avoids the threads jamming
and prevents premature carriage wear.
12
Diamond tipped drills
• Should be handled with care to obtain
maximum life (they may be re-tipped for
economy).
• They may be permanently damaged by
hard impacts on hard surfaces, by
compression under a load or by using
unsuitable tools on the tube for removal
(chain wrench, pipe wrench).
13
Problems while boring
Drill jammed in bore hole
• If the motor stops suddenly, turn it off
immediately.
• Check the water flow and correct if
necessary.
• Try to remove the drill using the wheel
without forcing.
• - Under no circumstances should you
try to release the tool by bump-starting it .
If the drill can be removed, remove the
core as described in paragraph 10, clean
to the base of the bore hole and start
boring again.
If the drill cannot be removed, put the
appropriate spanner on the drill
connector and rotate it backwards and
forwards while pressing on the wheel.
When the drill has been removed from
the hole, remove the core, clean the
hole and start boring again.
• In extreme cases, when it is impossible
to free the drill, it is possible to recover
some of the diamond tipped strip by over-
boring. This entails boring around the
jammed drill along the same axis. The
drill used should have an interior
diameter 10 mm greater than the
diameter of the jammed drill. Continue as
for normal boring.
Borer comes loose during operation
• Stop the motor immediately and check
the borer mountings.
Expanding bolt mounting
• Check that the locking screw is tight, and
that the expanding bolt is well anchored
(if it comes out of the wall it can not be
properly tightened). Drill another
anchoring hole and reposition the
machine.
• As it is very difficult to align with an
existing hole, it is better to move the axis
of the hole slightly if possible, or to bore
using the next larger size of drill.
Suction mounting
• Check that the levelling screws are tight,
and that the vacuum pump is operating
correctly using the pressure gauge. If the
pressure drop is too low, check the base
seal and replace if necessary. Check the
surface of the material in the region of the
mounting: surface faults might cause air
leakage. Move the mounting. The suction
could tend to tear off a superficial layer
from the material (eg: a skim): if this
happens, choose another mounting
method.
Unusual vibrations
• Normally caused by the core breaking off
within the drill causing an unbalanced
load.
• Stop the motor immediately.
Page 11

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