Komatsu PC300LC-8 Operation & Maintenance Manual page 214

OPERATION
MACHINE OPERATIONS AND CONTROLS
Operations Digging at an Angle without Engaging Teeth
Do not swing the upper structure when digging hard rock at a
position higher than the machine if the bucket teeth will not
penetrate the rock. The teeth will slip on the rock surface and
generate excessive vibration of the machine, and this will lead to
cracking of the work equipment or frame.
In addition, if the bucket teeth slip and hit the rock, there will be
excessive impact load on the work equipment and frame, and this
will reduce the service life of the machine.
Digging Hard Rocky Ground
Do not attempt to directly excavate hard rocky ground with the work equipment. It is better to excavate it after
breaking up by some other means. This will not only save the machine from damage but will make for better
economy.
Operations When Machine is Not Stable
Do not carry out operations when the machine is not in a stable
position. This will generate a twisting load on the frame and other
parts and will reduce the service life of the machine.
When carrying out operations in such a place, pile soil under the
front of the track or take other measures to stabilize the machine
before starting the operation.
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