SAFETY CLUTCH
This machine is equipped with a mechanical clutch to protect the operator and machine from excessive torque
forces. After the clutch slips many times, it will become worn and slip at lower and lower torque levels. When
this happens, it must be serviced by an authorized service provider. The recommended torque of the clutch nut
is 21 Nm.
DIAMOND CORE DRILLING
1.
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.
2.
Once in the cut, use steady feed pressure .
3.
When breaking through, hold the machine tightly and reduce feed pressure .
WARNING: Always keep your face away from the machine.
The diamond impregnated segments in diamond core bit operate on a principle of controlled erosion. The
bond matrix holding the diamonds is continually worn away by abrasion with the work piece, exposing
the harder diamonds to stand proud from the bond matrix.
With not enough erosion of the bond matrix (the diamonds not exposed) and the bit becomes dull.
This is called glazing. If the bit seems to refuse to cut anymore, it is glazed.
See below: "SHARPENING A GLAZED BIT "
Never use a sharp motion or the bit will be damaged. Conversely, don't feed too gently or the diamond
segments will become glazed. Keep the bit steadily working.
If holding by hand, take great care to keep the bit aligned to the hole. If the bit is crooked, it will easily bind.
CAUTION: If the bit gets stuck, do not try to rock it loose by turning the switch on and off. That is
hazardous and could damage the motor. Rather, unplug the machine and use a wrench on the bit
mounting to work it loose.
CAUTION: Drilling operations are very stressful to the motor and at the end of the cut, the motor
temperature will be very hot, always run the motor at no load for a few minutes until the temperature
returns to a normal range before shutting off.
Then turn off the switch and allow the coasting bit to stop before setting it down.
RESHARPENING A GLAZED BIT
If the bit becomes glazed, resharpen and true it up is by dressing with an appropriate alumina oxide or
silicon carbide dressing stone. Simply drill into the stone as many times as necessary to restore its cutting
performance.
VIBRATION TROUBLESHOOTING
If vibration occurs and it is not caused by embedded steel, stop drilling to find the cause and remedy.
CAUTION: Do not operate with vibration or there will be serious hazard and the diamond core bit
will surely be destroyed.
GB
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