Maintenance; Replacing Carbon Brushes - Makita DTW250 Instruction Manual

High tensile bolt
N m
(kgf cm)
200(2,040)
180(1,836)
160(1,632)
140(1,428)
120(1,224)
100(1,020)
80(816)
60(612)
40(408)
20(204)
0
1.0
Fastening time (S)
007535
NOTE:
Hold the tool pointed straight at the bolt or nut.
•
Excessive fastening torque may damage the
•
bolt/nut or socket. Before starting your job, always
perform a test operation to determine the proper
fastening time for your bolt or nut.
If the tool is operated continuously until the battery
•
cartridge has discharged, allow the tool to rest for
15 minutes before proceeding with a fresh battery
cartridge.
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. Socket
Failure to use the correct size socket will cause
•
a reduction in the fastening torque.
A worn socket (wear on the hex end or square
•
end) 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 use of the universal joint or the extension bar
somewhat reduces the fastening force of the
impact wrench. Compensate by fastening for a
longer period of time.
M14
M14
M12
M10
M12
M10
2.0 3.0
5. The manner of holding the tool or the material of
driving position to be fastened will affect the torque.
6. 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 attempting to
perform inspection or maintenance.
Never use gasoline, benzine, thinner, alcohol or the
•
like. Discoloration, deformation or cracks may
result.

Replacing carbon brushes

006258
Replace when they wear down to the limit mark. Keep
the carbon brushes clean and free to slip in the holders.
Both carbon brushes should be replaced at the same
time. Use only identical carbon brushes.
Use a screwdriver to remove two screws then remove
the rear cover.
007458
Raise the arm part of the spring and then place it in the
recessed part of the housing with a slotted bit
screwdriver of slender shaft or the like.
1
007459
8
1. Limit mark
1
1. Rear cover
1
2. Screws
2
1. Spring
2. Arm
3. Recessed part
3
2