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Bolt Tightening Conditions
0.5
0.0
1.0
1.5
2.0
3.0
2.5
M6
M12
M8
M10
50
100
150
N
⋅
m
(k
g
f-cm)
Tightening torque
Tightening time (Sec.)
M8, M10 x 35mm. M1 x 45mm
High tensile bolt
(Bolt size: Millimeters)
0.5
0.0
1.0
1.5
2.0
3.0
2.5
M6
M12
M14
M8
M10
50
100
150
N
⋅
m
(k
g
f-cm)
Tightening torque
Tightening time (Sec.)
M10 x 35mm. M1, M14, M16 x 45mm
Standard bolt
Bolt
Nut
Washer
Steel plate
thickness10 mm (3/8")
Washer
Spring washer
Tightening conditions
• The following bolts are used.
Standard bolts: Strength type 4.8
High tensile type 1.9
4.8
Explanation of the strength type
Bolt yield point
(80% of tensile strength)
3 k
g
f/mm
(45000psi)
Bolt tensile strength
40 k
g
f/mm
(56000psi)
) Tightening time
Longer tightening time results in in-
creased tightening torque. Excessive
tightening, however, adds no value
and reduces the life of the tool.
3) Different bolt diameters
The size of the bolt diameter affects
the tightening torque.
Generally, as the bolt diameter in-
creases, tightening torque rises.
4) Tightening conditions
Tightening torque will vary, even with
the same bolt, according to grade,
length, and torque coefficient (the fixed
coefficient indicated by the manufac-
turer upon production).
Tightening torque will vary, even with
the same bolting material (e.g. steel),
according to the surface finish.
Torque is greatly reduced when the
bolt and nut start turning together.
5) Socket play
Torque is lowered as the six-sid-
ed configuration of the socket of the
wrong size is used to tighten a bolt.
6) Switch (Variable speed control trigger)
Torque is lowered if the unit is used
with the switch not fully depressed.
7) Effect of Connecting Adapter
The tightening torque will be lowered
through the use of a universal joint or
a socket adapter.
• Universal joint
• Socket adapter
EY7542(UL).indb 14
2007/07/25 11:34:13
