10
7) DIAMOND CORE DRILLING
WARNING: When coring through a floor, the core will fall down. Take precautions to avoid injury or
damage below.
NOTE: When drilling with a new bit for the first time, use less than normal feed pressure for a time
until it breaks-in.
1.
Press the “Reset” button on the PRCD interrupter device to energize the circuit to the machine. Then
squeeze the trigger switch to turn the machine on.
WARNING: Hold the machine tightly with both hands to counteract the torque reaction force when
the bit begins to turn.
2.
Open the water valve slightly and very gently begin the cut. If holding by hand, start the cut by
approaching at an angle of about 30 degrees to the cutting surface. (A large piece of wood with a large V
notch cut in it will help prevent the bit from wandering at the beginning.) Once about a third of the arc is
cut, straighten the bit to the correct perpendicular angle while keeping enough feed pressure on the bit
to prevent it from wandering.
(If using a rig, use very light feed pressure to prevent the bit from wandering until the bit is fully
penetrated into the cut.)
3.
Make adjustments to the water feed as needed. The water leaving the cut should be a solid colored
slurry with about the consistency of milk. If the exiting water is clear, then you may reduce the water flow.
If the exiting water is thick and muddy, then increase the water. It’s very important that the water
has enough pressure to flush cutting debris out of the cut.
4.
Once in the cut, use steady feed pressure for about 30 seconds, then back off feed pressure for a few
seconds to allow cutting debris to escape the kerf (cutting area) and for the cutting surface of the bit to
cool. This has the added benefit of allowing the motor to remain within a good working temperature.
Repeat this cycle until finished.
5.
When the cut is almost finished and the bit is about to break through, the bit will be very liable to get
stuck. Take extra care gripping the machine tightly and reduce feed pressure at this point.
WARNING: Whenever drilling by hand, always hold the drill in a
position so that you can resist the considerable twisting forces
created when the bit grabs. Never operate without the side
handle tightly in place.
WARNING: When the bit grabs, the machine will always twist in
the counterclockwise direction. If you are drilling into the floor,
make sure that the side handle is in front of your left leg, never
between your legs.
WARNING: Always keep your face away from the machine.
Arrange the power supply cable with minimal slack and oriented in such a way that if the machine gets out of
control and spins, it will immediately unplug its own cable.
The diamond impregnated segments in a wet type (sintered) diamond core bit operate on a principle of
Right
Wrong
