Operational Cautions - Hitachi Koki WH 12DM2 Instrucciones De Manejo

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5. Number of screws tightenings possible (WH12DM2,
WH9DM2, WH12DMR)
Please refer to the table below for the number of
screw tightened possible with one charge.
WH12DM2, WH12DMR (EB1230HL)
Screw used
Wood screw ø4 × 50
(Soft wood)
Machine screw M8 × 16 Approx. 1750 Approx. 1660
WH9DM2 (EB930H)
Screw used
Wood screw ø4 × 50
(Soft wood)
Machine screw M8 × 16
These values may vary slightly, according to
surrounding temperature and battery characteristics.
6. Number of bolt tightened possible (WR12DM2,
WR9DM2)
Please refer to the table below for the number of bolt
tightened possible with one charge.
WR12DM2 (EB1230HL)
Bolt used
M12 High tension bolt
WR9DM2 (EB930H)
Bolt used
M12 High tension bolt
These values may vary slightly, according to
surrounding temperature and battery characteristics.
NOTE
The use of the battery EB1230HL, EB930H in a cold
condition (below 0 degree Centigrade) 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 protector, 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
13
No. of tightenings
WH12DM2 WH12DMR
Approx. 790 Approx. 750
No. of tightenings
Approx. 530
Approx. 1690
No. of tightenings
Approx. 180
No. of tightenings
Approx. 120
the electronic circuit parts may overheat and be
damaged.
3. Tightening torque
Refer to Fig. 22, 23, 24, 25 and Fig. 26 for the tightening
torque of bolts (according to size), under the
conditions shown in Fig. 27. Please use this example
as a general reference, as tightening torque will vary
according to tightening conditions.
NOTE
If a long striking time is used, screws will be strongly
tightened. This may cause the screw to break, or may
damage the tip of the bit.
If the unit is held at an angle to the screw being
tightened, the head of the screw may be damaged, or
the specified torque may not be transmitted to the
screw. Always keep the unit and the screw being
tightened in a straight line.
4. 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.
5. 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 operation time. Use
the correct operating time for the bolt.
6. 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.
7. 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. 22, 23, 24, 25 and 26)
(3) Diameter of bolt
The tightening torque differs with the diameter of the
bolt as shown in Fig. 22, 23, 24, 25 and 26. 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.