Norton clipper CDR 353 Operating Instructions Manual page 18

VERS.2015.05.19

The core bit goes ahead very slowly.

The force you have to make on the hand wheel increases.

The water going out of the hole is clear and there are some metallic splints in it.
You are going through the steel rods for reinforced concrete. Follow these instructions:

If possible, select a lower gear. Remember that you must firstly take the core bit out of
the hole and switch the motor off in order to change from gear.

Reduce the thrust on the core bit.
Once you have finished cutting the rods, you can reselect the initial gear and drilling speed.
5.2.6 Mechanical clutch
The motor is equipped with a mechanical clutch. It protects against mechanical overload of
the motor. However, the motor might be damaged if it works longer than two seconds.
Therefore reduce the drilling force and switch the motor off.
5.2.7 Breakaway of a segment
When diamond segments, slivers of steel or parts of your drilled material come away during
drilling, and prevent the core bit from drilling, abandon the hole and make another hole, with
the same axis of the first but with an larger diameter (15-20mm).
5.2.8 End of the drilling
When you have made the hole you want to drill:

Lift the core bit out of the hole.

Stop the motor by using the switch and not the P.R.C.D.

Stop the water supply.
5.2.9 Pulling the core out of the bit

Unscrew the core bit from the motor axle.

Hold the bit vertically.

Beat lightly the tube of core bit with a wood hammer until the core goes out. Never beat
the core bit with violence against a wall or with tools like hammers or wrenches.
Otherwise, you may distort the tube, preventing the core from coming out of the core bit
and the re-use of the bit.

If the core is stuck into the bit, try to crush it with a chisel. Be careful not to damage the
core bit.
5.2.10 Pulling the core out of the hole (blind holes)

Using a wedge or a lever, snap the core.

To extract the core out of the hole use the special pliers or a wire loop, or make a little
hole into the top of the core and put into it an eyebolt to pull up and remove the core.
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Kit CDR 353 + NBM 351_MAN_EN