6MANTA III
Revision 12/04, Effective Date December 6, 2004
7
MANTA III Revision 12/04, Effective Date December 6, 2004
When drilling through concrete floors, the core will generally drop from the diamond bit. Caution should be
provided for people and property below the drilling area.
1. Ensure that you have read and fully understand the complete operation of the Manta III Core Drill you
have purchased prior to commencing drilling operations.
2. Select and install a diamond core bit appropriate for the job. Note: Grease the bit threads to help
prevent the bit from seizing on the spindle due to surface corrosion.
3. Select either high or low gear speed according to the chart in the Drilling Speeds section of this manual.
(Do not shift speed when motor is on.)
4. Connect water hose to water swivel.
5. Secure the rig as described in the Securing the Rig section of this manual.
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 sliding 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 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.
The MK-Manta III Core Drill uses either a shear pin or a friction clutch to protect the gear and motor
against overload. The shear pin drives the outer portion of the drive spindle. If the motor should overload
the pin will shear. Extra shear pins are supplied or can be ordered from MK Diamond’s Customer Service.
Tighten only enough to remove the play. Do not over tighten. Another model features a friction clutch
rather than a shear pin to protect the motor and gears. If the motor overloads the clutch will begin to slip
and the bit will stop rotating. The clutch is factory-set and does not require adjustments. However, under
normal use, the clutch may start to slip at low torque. If this happens, refer to the motors Owner’s Manual.
Bits with permanently attached adapters simply screw directly onto the threads of the drill spindle. Ensure
that the end of the bit butts up squarely against the shoulder on the spindle.
*Thread anti-clockwise to attach core bit.
*Thread clockwise to loosen.
The MK-Manta III Core Drill, equipped with either the Milwaukee, Core Bore or Eibenstock motor, has a 1
1/4”-7 thread. For bits with other threads, use a shaft coupling. After a bit has been mounted, turn the
power on and check that there is a minimum of run-out or wobble.
To reduce the risk of injury, always unplug tool before attaching or removing accessories. Only use
specifically recommended accessories. Others may be hazardous.
Mounting Bits
Drilling Procedure
Shear Pin and Clutch Protection
WARNING
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WARNING
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WARNING
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CAUTION
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