Operational Cautions - Hitachi WR 14DM Mode D'emploi

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3. Switch operation
When the trigger switch is depressed, the tool
rotates. When the trigger is released, the tool stops.
The rotational speed can be controlled by varying
the amount that the trigger switch is pulled. Speed
is low when the trigger switch is pulled slightly and
increases as the trigger switch is pulled more.
4. Tightening and loosening bolts
A hex socket matching the bolt or nut must first
be selected. Then mount the socket on the anvil,
and grip the nut to be tightened with the hex socket.
Holding the wrench in line with the bolt, press the
power switch to impact the nut for several seconds.
If the nut is only loosely fitted to the bolt, the bolt
may turn wit the nut, therefore mistaking proper
tightening. In this case, stop impact on the nut and
hold the bolt head with a wrench before restarting
impact, or manually tighten the bolt and nut to
prevent them slipping.
5. Number of bolt tightened possible
Please refer to the table below for the number of
bolt tightened possible with one charge.
EB1430H
Bolt used
M16 × 55 (F10T)
These values may vary slightly, according to
surrounding temperature and battery characteristics.
NOTE:
The use of the battery EB1430H in a cold condition
(below 0°C) can sometimes result in the weakened
tightening torque and reduced amount of work.
This, however, is a temporary phenomenon, and
returns to normal when the battery warms up.

OPERATIONAL CAUTIONS

1. Resting the unit after continuous work
After use for continuous bolt-tightening work, rest
the unit for 15 minutes or so when replacing the
battery. The temperature of the motor, switch, etc.,
will rise if the work is started again immediately
after battery replacement, eventually resulting in
burnout.
NOTE:
Do not touch the hammer case, as it gets very hot
during continuous work.
2. Cautions on use of the speed control switch
This switch has a built-in, electronic circuit which
steplessly varies the rotation speed. Consequently,
when the switch trigger is pulled only slightly (low
speed rotation) and the motor is stopped while
continuously driving in screws, the components of
the electronic circuit parts may overheat and be
damaged.
3. Tightening torque
Refer to Fig. 16 for the tightening torque of bolts
(according to size), under the conditions shown in
Fig. 17. Please use this example as a general
reference, as tightening torque will vary according
to tightening conditions.
11
No. of tightenings
Approx. 126
Tightening torque varies, depending on the battery's
charge level. Fig. 18 shows an example of the
relationship between tightening torque and the
number of tightenings, for WR14DM. As shown,
tightening torque gradually weakens with the
increase in the number of tightenings. In particular,
as the torque decreases very close to the complete
discharge ("a" margin in graph), the unit's impact
weakens, the number of time impacts declines and
tightening torque drops off abruptly. If this occurs,
check torque level, then recharge the battery if
necessary.
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 proportionate 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. (See Fig. 16)
(3) Diameter of bolt
The tightening torque differs with the diameter of
the bolt as shown in Fig. 16. 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
The tightening torque is reduced a little when an
extension bar, universal joint or a long socketis
used.
(6) Clearance of the socket
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. Matching socket and bolt sizes are shown
in Table 1 and 2.