10
MANTA I
Revision 03/05, Effective Date March 2, 2005
11
MANTA I
Revision 03/05, Effective Date March 2, 2005
If using the vacuum base, do not continue operations unless the vacuum gauge
reads more than 20 inches of mercury. Normally, the gauge will read 23 inches
or more.
6. Turn the motor switch on the Control box ON. Turn the water ON so that an
adequate flow of water is supplied through the water swivel, to the bit. Hold the
handle and slightly loosen the carriage lock knob. Slowly rotate the handle to
lower the bit into the work piece - apply steady even pressure.
Note:
To prevent the bit from wandering, always use a light load to start the
hole and wait for the diamond tip of the bit to penetrate the work surface before
increasing the load.
7. Use consistent pressure so that the bit cuts consistently. Insufficient pressure
will cause the diamond core bit to glaze over. Too much pressure will overload
the motor and crush the diamonds. Use the ammeter on the Control box as a
guide for proper pressure.
If the rig shifts during drilling, stop the motor, reposition the rig, and resume
drilling.
8. Monitor the water flow. If the water flow is adequate, the water leaving the cut
should be slightly sludgy. When cutting metal rebar, the water should have a
gray metal coloring.
Notice:
When drilling into prestressed concrete the bit may cut into the hardened
steel cable under tension. As the bit cuts through each strand, the tension in the
cable is released. The diamond segments on the bit crown can be damaged by
the loose wires. The best prevention for bit damage is to use a core bit designed
especially for drilling in prestressed concrete.
9. When the cut is complete, keep the drill motor on and rotate the handle to
bring the bit up out of the hole. The bit may become stuck if the motor is turned
off before the bit is completely clear of the hole. Once the bit is clear of the hole,
tighten the carraige lock knob, turn off the motor and the water supply.
Note:
Normally the core will drop out of the bit, and remain in the hole. However,
in cases where the core sticks in the bit, it is sometimes necessary to push
the core up and down with the water running to allow the core to drop out.
Sometimes very light tapping on the barrel of the bit with a piece of wood will
loosen the core.
Perform this action only with the motor turned off and the unit unplugged
to prevent accidental starting and injury. Exercise extreme caution in hand
placement when removing a stuck core, as it can be heavy and inflict injury.
WARNING
!
CAUTION
!
CAUTION
!
