Hitachi WH 12DM2 Instructions De Sécurité Et Mode D'emploi page 23

(6) Clearance of the socket (WR12DM2, WR9DM2)
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 4, 5, 6 and 7.
(7) Tightening torque varies, depending on the battery's charge level (WR12DM2, WR9DM2)
Fig. 22 and 23 show an example of the relationship between tightening torque and the
number of tightenings. 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.
<For WH12DM2>
kgf·cm
3/8"×1-5/32"
N·m
(in-lbs)
(M10×30)
100
1000
High strength bolt
(868)
80
800
(695)
60
600
(521)
40
400
(347)
Ordinary bolt
20
200
(174)
0
0
0 1
Tightening time: sec
(Steel plate thickness
t = 3/8" (10 mm))
kgf·cm
N·m
(in-lbs)
140
1400
(1215)
120
1200
(1042)
1000 100
(868)
800
80
(694)
60
600
(521)
40
400
(347)
20
200
(174)
0
2 3
Tightening time: sec
(Steel plate thickness
t = 1" (25 mm))
15/32"×1-3/4"
(M12×45)
High strength bolt
Ordinary bolt
0
0 1 2 3
Fig. 17
kgf·cm
9/16"×1-15/16"
N·m
(in-lbs)
(M14×50)
140
1400
(1215)
120
1200
(1042)
High strength bolt
100
1000
(868)
80
800
(694)
60
Ordinary bolt
600
(521)
40
400
(347)
20
200
(174)
0
0
0 1
Tightening time: sec
(Steel plate thickness
t = 1" (25 mm))
English
2 3
23