Operator’s instructions
7. Drilling
78
reduce rotation speed as much as possible without causing the drill string to
rotate jerkily
check the drill feed pressure and set it to the recommended value.
Reduce percussion pressure to below the basic setting (5-10 bar). A reasonable
reduction in penetration rate must be accepted.
d. Check and/or adjust damper pressure so that the shank adapter is in “float posi-
tion”.
Difficulties in loosening the coupling sleeve
The best method of loosening the coupling sleeve is to “drill” the last few centimetres
without feed pressure and rotation, leaving percussion active for a few seconds to
break loose the coupling sleeve.
•Make sure the RPC-F system is set correctly. An RPC-F system that is set too high
causes excessive torque in the coupling sleeve.
Hole deflection
1. Try to drill with as low a drill feed pressure as possible.
2. Check the condition of the drill bit.
3. Use TAC pipes, drop centre bits.
4. Only use flushing air and rotation during overload.
5. Drill the first drill steel with reduced drilling for at least half of the drill steel in
order to minimise hole deflection at the start of the hole.
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