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VI
. MAINTENANCE
Use only a dry, soft cloth for wiping the unit.
Do not use a damp cloth, thinner, benzine,
or other volatile solvents for cleaning.
VII
. TIGHTENING TORQUE
The power required for tightening a bolt will
vary, according to bolt material and size, as
well as the material being bolted. Choose
the length of tightening time accordingly.
Reference values are provided below.
(They may vary according to tightening conditions.)

Factors Affecting Tighten-

ing Torque

The tightening torque is affected by a wide
variety of factors including the followings.
After tightening, always check the torque
with a torque wrench.
1) Voltage
When the battery pack becomes near-
ly discharged, the voltage decreases and
the tightening torque drops.

Bolt Tightening Conditions

0.50.0 1.0 1.5 2.0 3.02.5
M10
M8
M12
N ⋅ m
(kgf-cm)
49.0
(500)
98.0
(1000)
147.0
(1500)
Tightening torque
Tightening time (Sec.)
M8, M10 x 35 mm. M12 x 45 mm
High tensile bolt
(Bolt size: Millimeters)
0.50.0 1.0 1.5 2.0 3.02.5
M16
M12
M14
M10
49.0
(500)
98.0
(1000)
147.0
(1500)
196.0
(2000)
N ⋅ m
(kgf-cm)
Tightening torque
Tightening time (Sec.)
M10 x 35 mm. M12, M14, M16 x 45 mm
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 12.9
4.8
Explanation of the strength type
Bolt yield point
(80% of tensile strength)
32 kgf/mm2 (45000psi)
Bolt tensile strength
40 kgf/mm2 (56000psi)
2) Tightening time
Longer tightening time results in increased
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 a ffects the
tightening torque.
Generally, as the bolt diameter increases,
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 indi-
cated by the manufacturer upon produc-
tion).
EY7540(UL).indb 12 2006/09/07 16:58:36