Fig.3 - 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
Fastening time (S)
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 fasten-
ing torque will differ according to the diame-
ter 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.
M14
M14
M12
M10
M12
M10
1.0 2.0
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.
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 reduc-
tion in the fastening torque.
MAINTENANCE
CAUTION:
• Always be sure that the tool is switched off and
the battery cartridge is removed before attempt-
ing to perform inspection or maintenance.
• Never use gasoline, benzine, thinner, alcohol
3.0
or the like. Discoloration, deformation or cracks
may result.
Replacing carbon brushes
► Fig.11: 1. Limit mark
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.
► Fig.12: 1. Rear cover 2. Screws
Raise the arm part of the spring and then place it in the
recessed part of the housing with a slotted bit screw-
driver of slender shaft or the like.
► Fig.13: 1. Spring 2. Arm 3. Recessed part
Use pliers to remove the carbon brush caps of the
carbon brushes. Take out the worn carbon brushes,
insert the new ones and replace the carbon brush caps
in reverse.
► Fig.14: 1. Carbon brush cap
► Fig.15: 1. Hole 2. Carbon brush cap
Make sure that the carbon brush cap have fit into the
holes in brush holders securely.
Reinstall the rear cover and tighten two screws
securely.
To maintain product SAFETY and RELIABILITY, repairs,
any other maintenance or adjustment should be per-
formed by Makita Authorized Service Centers, always
using Makita replacement parts.
8 ENGLISH