MK Diamond MK-MANTA III - Manual (Page 15)

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When drilling holes that are longer than the core bit, follow the steps below.
If the rig shifts during drilling, stop the motor, reposition the rig, and resume
drilling.
Perform the above action only with the motor turned off and the unit un-
plugged to prevent accidental starting and injury. Exercise extreme caution in
hand placement when removing a stuck core, as the core can be heavy and
inflict injury.
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 dam-
aged by the loose wires. The best prevention for bit damage is to use a core
bit designed especially for drilling in prestressed concrete.
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.
DEEP DRILLING
CAUTION
CAUTION
NOTICE:
NOTE:
1. Begin drilling the hole as usual. When you have drilled to the length of the bit, retract the bit
from the hole and turn off the motor and water as usual.
2. Break off the core by driving a chisel or slender wedge into the circular kerf. Remove the
core using core tongs, bent music wire or anchor bolts.
3. After removing the core, insert the bit carefully into the hole, attach a bit extension to the bit
and core drill rig, then continue drilling as usual.
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.
9. When the cut is complete, keep the drill motor on and rotate the sliding 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 carriage lock knob,
turn off the motor and the water supply.
MANTA CORE DRILL III OPERATION