AGP TC402 Bedienungsanleitung Seite 10

has enough pressure to flush cutting debris out of the cut.
2. Once in the cut, use steady feed pressure .
3.
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: Always keep your face away from the machine.
ADDITIONAL SPECIAL INSTRUCTIONS FOR WET DRILLING
The diamond impregnated segments in a wet type (sintered) 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 too much water and not enough feed pressure, there would not be adequate erosion of the bond
matrix (the diamonds not exposed) and the bit becomes dull (diamond segments polish smooth).
This is called glazing. If the bit seems to refuse to cut anymore, it is glazed. See below: "SHARPENING A
GLAZED BIT "
Don't feed too gently or the diamond segments will become glazed. Keep the bit steadily working, but
don't be abusive or give the bit shock impacts into the work surface.
Take great care to keep the bit aligned to the hole. If the bit is crooked, it will easily bind.
If the cut is very deep, the core plug may be obstructing the flow of cooling water. In this case, stop drilling, and
chisel out the core plug before continuing.
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.
If embedded steel such as rebar is encountered take special care. When the steel is encountered, the water
will generally go clear and vibration will begin. Change to a lower gear if available. Reduce the feed pressure
by about 1/3 and let the bit go at its own pace, if there is too much vibration the bit will be destroyed.
Once the steel is passed, continue normally.
When the cut is finished keep the motor running until the bit is removed from the cut to avoid it getting
stuck.
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.
RESHARPENING A GLAZED BIT
If the bit becomes glazed, resharpen by dressing with an appropriate alumina oxide or silicon carbide dressing
stone. Simply drill into the stick as many times as necessary to restore its cutting performance.
GB
(Wet bits only)
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