8
OPERATION Theproper fastening torque may differ depending upon the
kindor size of the bolt. The relation between fastening torque
andfastening time is shown in the figures.
OPERATION
Hold the tool firmly and place the socket overthe bolt or nut.
Turnthe tool on and fasten for the proper fastening time.
NOTE:
• When fastening screw M8 (5/16”) or smaller, carefully
adjust pressure on the switchtrigger so that the screw is
notdamaged.
• Hold the tool pointed straight at the bolt or nut without
applyingexcessive pressure on the tool.
• If you fastenthe bolt for a time longer than shown in the
figures, the bolt or the socket may be overstressed,
damaged,etc. Before starting your job, always perform a
test operation to determine the proper fastening time for
your bolt. Especially for the bolt over than M8 (5/16”),
perform the above test operation to preventthe trouble
onsocket or bolt, etc.
The fastening torque is affected by a wide varietyof factors
including the following. After fastening, always check the
torquewith a t orque wrench.
1. Socket
• Failure to use the correct size socket will cause a
reductionin the fastening torque.
• A worn socket (wear on the hex end or square end)
will cause a reductionin the fastening torque.
2. Bolt
• Even though the torque coefficient and the class of
bolt are the same, the proper fastening torque will
differaccording to the diameter of bolt.
• Eventhough the diameters of bolts are the same, the
proper fastening torque will differ according to the
torque coefficient, the class of bolt and the bolt
length.
3. The manner of holding the tool or the material of driving
positionto be fastened will affect the torque.
4. Operating the tool at lows peed will cause a reduction in
thefastening torque.
001658
M14(9/16”)
1
80
(58)
60
(43)
40
(29)
20
(14)
023
N·m
(ft·lbs)
M14(9/16”)
M12(1/2”)
100
(72)
120
(86)
140
(100)
M16(5/8”)
M16(5/8”)
M12(1/2”)
Fasteningtime
Fasteningtorque
Seconds
Standardbolt
001659
M10(3/8”)
1
80
(58)
60
(43)
40
(29)
20
(14)
023
N·m
(ft·lbs)
M10(3/8”)
M8(5/16”)
100
(72)
120
(86)
140
(100)
M12(1/2”)
M12(1/2”)
M8(5/16”)
Fasteningtime
Fasteningtorque
Seconds
Hightensile bolt