Komatsu PC118MR-8 Operation And Maintenance Manual page 411

OPTIONAL EQUIPMENT
RECOMMENDED ATTACHMENT OPERATIONS
When applying impact, push the chisel against the impact
surface and operate so that the chassis rises approximately 5
cm (2 in) off the ground. Do not let the machine come further off
the ground than this amount.
When applying continuous impact to the same impact surface,
if the chisel does not penetrate or break the surface within 1
minute, change the point of impact and carry out breaking
operations closer to the edge.
The direction of penetration of the chisel and the direction of
the breaker body will gradually move out of line with each
other, always adjust the bucket cylinder to keep them aligned.
Always keep the chisel pressed against the impact surface
properly to prevent using the impact force when there is no
resistance.
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