Maintenance And Inspection - Hitachi Koki WH 18DBDL Handling Instructions Manual

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3. Use a tightening time suitable for the screw
The appropriate torque for a screw differs according
to the material and size of the screw, and the material
being screwed etc., so please use a tightening time
suitable for the screw. In particular, if a long tightening
time is used in the case of screws smaller than M8,
there is a danger of the screw breaking, so please
confirm the tightening time and the tightening torque
beforehand.
4. Work at a tightening torque suitable for the bolt
under impact
The optimum tightening torque for nuts or bolts differs
with material and size of the nuts or bolts. An
excessively large tightening torque for a small bolt
may stretch or break the bolt. The tightening torque
increases in proportion to the operaton time. Use the
correct operating time for the bolt.
5. Holding the tool
Hold the impact wrench firmly with both hands. In
this case hold the wrench in line with the bolt.
It is not necessary to push the wrench very hard.
Hold the wrench with a force just sufficient to
counteract the impact force.
6. Confirm the tightening torque
The following factors contribute to a reduction of the
tightening torque. So confirm the actual tightening
torque needed by screwing up some bolts before the
job with a hand torque wrench. Factors affecting the
tightening torque are as follows.
(1) Voltage
When the discharge margin is reached, voltage
decreases and tightening torque is lowered.
(2) Operating time
The tightening torque increases when the operating
time increases. But the tightening torque does not
increase above a certain value even if the tool is
driven for a long time.
(3) Diameter of bolt
The tightening torque differs with the diameter of the
bolt. Generally a larger diameter bolt requires larger
tightening torque.
(4) Tightening conditions
The tightening torque differs according to the torque
ratio; class, and length of bolts even when bolts with
the same size threads are used. The tightening torque
also differs according to the condition of the surface
of workpiece through which the bolts are to be
tightened. When the bolt and nut turn together, torque
is greatly reduced.
(5) Using optional parts (WR14DBDL / WR18DBDL)
The tightening torque is reduced a little when an
extension bar, universal joint or a long socket is
used.
(6) Clearance of the socket (WR14DBDL / WR18DBDL)
A worn or deformed hex. or a square-holed socket
will not give an adequate tightness to the fitting
between the nut or anvil, consequently resulting in
loss of tightening torque.
Using an improper socket which does not match to
the bolt will result in an insufficient tightening torque.
(7) Tightening torque varies, depending on the battery's
charge level.
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MAINTENANCE AND INSPECTION

1. Inspecting the driver bit (WH14DBDL / WH18DBDL)
Using a broken bit or one with a worn out tip is
dangerous because the bit can slip. Replace it.
2. Inspecting the socket (WR14DBDL / WR18DBDL)
A worn or deformed hex. or a square-holed socket
will not give an adequate tightness to the fitting
between the nut or anvil, consequently resulting in
loss of tightening torque. Pay attention to wear of a
socket holes periodically, and replace with a new one
if needed.
3. Inspecting the mounting screws
Regularly inspect all mounting screws and ensure
that they are properly tightened. Should any of the
screws be loose, retighten them immediately. Failure
to do so may result in serious hazard.
4. Maintenance of the motor
The motor unit winding is the very "heart" of the
power tool.
Exercise due care to ensure the winding does not
become damaged and/or wet with oil or water.
5. Cleaning of the outside
When the impact driver is stained, wipe with a soft
dry cloth or a cloth moistened with soapy water. Do
not use chloric solvents, gasoline or paint thinner, as
they melt plastics.
6. Storage
Store the impact driver in a place in which the
temperature is less than 40°C, and out of reach of
children.
NOTE
Storing Lithium Batteries
Make sure the lithium batteries have been fully
charged before storing them.
Prolonged storage of batteries with a low charge
may result in performance deterioration or storage
capacity reduction, and may also render the batteries
incapable of holding a charge.
There are cases in which repeatedly charging and
discharging the batteries two to five times will result
in the full capacity being restored.
Replace the batteries in the event of the capacity not
being restored after repeated recharges.
7. Service parts list
A: Item No.
B: Code No.
C: No. Used
D: Remarks
CAUTION
Repair, modification and inspection of Hitachi Power
Tools must be carried out by a Hitachi Authorized
Service Center.
This Parts List will be helpful if presented with the
tool to the Hitachi Authorized Service Center when
requesting repair or other maintenance.
In the operation and maintenance of power tools,
the safety regulations and standards prescribed in
each country must be observed.
MODIFICATIONS
Hitachi Power Tools are constantly being improved
and modified to incorporate the latest technological
advancements.
Accordingly, some parts (i.e. code numbers and/or
design) may be changed without prior notice.