9
Tools
Tools for removing the drill bit and top sub
from the DTH hammer
The threaded connections of the driver-chuck and top sub can be-
come very tightly tensioned during drilling. There are special tools
for removing the bit and top sub from the cylinder of the DTH
hammer, and these should be used whenever possible.
Bit removal tool
Wrench for pipe-jointing and top sub
Wrench Ordering No�
55 mm 8484-0211-43
65 mm 8484-0211-00
Loosening the threads of the hammer
If special tools like chain wrenches or other types of wrench are
used to break the hammer joints, then the tool must be attached
around the hammer cylinder as shown in the figure. Do not attach
at other points!
NB� Failure to attach the wrench as illustrated may result in dam
-
age to the cylinder. Any such damage will not quality for compnsa-
tion.
• Take great care when breaking the driver-chuck joint using
the bit removal tool in combination with reverse rotation. If
the shaft of the tool is not locked or touching the edge of the
feed beam, the shaft can turn with great force when breaking
the driver chuck joint.
• Keep your hands and clothing well clear of the hammer/drill
string when it is rotated. Entanglement can result in serious
injury.
• Blows against hammer or bit can cause fragments of metal
to fly. Always wear goggles when breaking joints.
DANGER
A
B
C
D
A
mm (in)
B
mm (in)
C
mm (in)
D
mm (in)
COP 32 90 (3.5) 50 (2.0) 60 (2.4) 110 (4.3)
COP 42 140 (5.5) 60 (2.4) 60 (2.4) 110 (4.3)
• Take great care when jointing the drill pipes and handling
the drill bit.
• Mind you fingers!
• Keep your clothing, hair, etc. well clear of rotating compo-
nents! Carelessness can result in serious injury.
WARNING
A� Breaking the driver-chuck joint using percussion only
Run the hammer into the rock or a thick plank.
• Apply light feed force.
• Carefully start the impact mechanism of the ham
-
mer.
• Stop the impact mechanism as soon as the driver-
chuck joint “cracks”.
• Run the hammer up the feed beam to a suitable
working height, and unthread the driver chuck and
drill bit.
N�B. Beware of the weight of the drill bit. It could
be too heavy to hold.
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