Maintenance - Makita BTD120 Instruction Manual

Operation (Fig. 6 & 7)
The proper fastening torque may differ depending
upon the kind or size of the screw/bolt, the material of
the workpiece to be fastened, etc. The relation
between fastening torque and fastening time is shown
in Fig. 6 for standard bolt or Fig. 7 for high tensile
bolt.
Hold the tool firmly and place the point of the driver bit
in the screw head. Apply forward pressure to the tool
to the extent that the bit will not slip off the screw and
turn the tool on to start operation.
NOTE:
• When fastening screw M8 or smaller, carefully
adjust pressure on the switch trigger so that the
screw is not damaged.
• Hold the tool pointed straight at the screw.
• If you tighten the screw for a time longer than shown
in the figures, the screw or the point of the driver bit
may be overstressed, stripped, damaged, etc.
Before starting your job, always perform a test
operation to determine the proper fastening time for
your screw.
The fastening torque is affected by a wide variety of
factors including the following.
After fastening, always check the torque with a torque
wrench.
1. When the battery cartridge is discharged almost
completely, voltage will drop and the fastening
torque will be reduced.
2. Driver bit or socket bit
Failure to use the correct size driver bit or socket
bit will cause a reduction in the fastening torque.
3. Bolt
• Even though the torque coefficient and the class
of bolt are the same, the proper fastening torque
will differ according to the diameter of bolt.
• Even though the diameters of bolts are the
same, the proper fastening torque will differ
according to the torque coefficient, the class of
bolt and the bolt length.
4. The manner of holding the tool or the material of
driving position to be fastened will affect the
torque.
5. Operating the tool at low speed will cause a
reduction in the fastening torque.

MAINTENANCE

CAUTION:
Always be sure that the tool is switched off and the
battery cartridge is removed before carrying out any
work on the tool.
Replacement of carbon brushes (Fig. 8 & 9)
Replace carbon brushes when they are worn down to
the limit mark. Both identical carbon brushes should
be replaced at the same time.
To maintain product safety and reliability, repairs,
maintenance or adjustment should be carried out by a
Makita Authorized Service Center.
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