English, Use a tightening time suitable for the screw, Fig. 15 – Hitachi WH14DM OM User Manual
Page 19: Bolt steel plate thickness t, Fig. 16 nut
English
19
0
1
2
3
0
kgf•cm
(in-lbs)
1600
1400
1200
1000
800
600
400
200
N•m
160
140
120
100
80
60
40
20
0
(1390)
(1218)
(1042)
(868)
(695)
(521)
(347)
(174)
0
1
2
3
0
kgf•cm
(in-lbs)
1600
1400
1200
1000
800
600
400
200
N•m
160
140
120
100
80
60
40
20
0
(1390)
(1218)
(1042)
(868)
(695)
(521)
(347)
(174)
Tightening time: sec
(Steel plate thickness
t = 3/8" (10 mm))
Tightening time: sec
(Steel plate thickness
t = 1" (25 mm))
Tightening torque
Tightening torque
High strenge bolt
High strenge bolt
Ordinary bolt
Ordinary bolt
3/8"×1-3/6"
(M10×30)
Fig. 15
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 5/16” (8 mm), there is a danger of the screw breaking, so please confirm the
tightening time and the tightening torque beforehand.
15/32"×1-3/4"
(M12×45)
Bolt
Steel plate
thickness t
Explanation of strength grade:
4 — Yield point of bolt: 45,500 psi (32 kgf/mm
2
)
8 — Pulling strength of bolt: 56,900 psi (40 kgf/mm
2
)
*The following bolt is used.
Ordinary bolt: Strength grade 4.8
High tensile bolt: Hardness division 12.9
(
)
Fig. 16
Nut
kgf•cm
(in-lbs)
1600
1400
1200
1000
800
600
400
200
N•m
160
140
120
100
80
60
40
20
0
(1390)
(1218)
(1042)
(868)
(695)
(521)
(347)
(174)
0
1
2
3
0
Ordinary bolt
Tightening time: sec
(Steel plate thickness
t = 1" (25 mm))
High strenge bolt
Tightening torque
9/16"×1-31/32"
(M14Ч50)