Factors affecting tightening torque – Panasonic EY7201 User Manual

Page 6

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– 10 –

– 11 –

0.5

1

1.5

2

3

2.5

M12

M10

M8

Tightening time (Sec.)

Tightening torque

M8.M10.M12 x 25mm Standard bolt
(Bolt size : Millimeters)

N

⋅ m

(kgf-cm)

19.6

(200)

39.2

(400)

58.8

(600)

78.5

(800)

98.1

(1000)

117.6

(1200)

M8.M10.M12 x 25mm High tensile bolt

0.5

1

1.5

2

3

2.5

M12

M10

M8

Tightening time (Sec.)

Tightening torque

N

⋅ m

(kgf-cm)

19.6

(200)

39.2

(400)

58.8

(600)

78.5

(800)

98.1

(1000)

117.6

(1200)

IV

.LAMP INDICATIONS

V

.MAINTENANCE

VI

.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 Tightening Torque

The tightening torque is affected by a wide variety of factors including the follow-
ings. After tightening, always check the torque with a torque wrench.

1) Voltage

When the battery pack becomes nearly discharged, the voltage decreases and the
tightening torque drops.

Red Flashing

Charger is plugged into the AC outlet.
Ready to charge.

Use only a dry, soft cloth for wiping the unit. Do not use a damp cloth, thinner, ben-
zine, or other volatile solvents for cleaning.

Battery pack is warm. Charging will begin
when temperature of battery pack drops.

Charging is not possible. Clogged with
dust or malfunction of the battery pack.

Now charging

Charging is completed.

Red Lit

Green Flashing quickly

Orange Lit

Orange Flashing

Bolt Tightening Conditions

Bolt

Washer

Washer

Spring washer

Steel plate
thickness 10 mm (3/8")

Nut

Tightening conditions
* The following bolts are used.

Standard bolts: Strength type 6.8
High tesile type 12.9

Explanation of the strength type

6.8

Bolt yield point
(80% of tenslie strength)
48 kgf/mm

2

(68,000psi)

Bolt tensile strength 60 kgf/mm

2

(85,000psi)

2) Tightening time

L o n g e r t i g h t n i n g t i m e r e s u l t s i n
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 affects
the tightening torque.
G e n e r a l l y , a s t h e b o l t d i a m e t e r
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 indicated by the
manufacturer upon production).

• Tightening torque will vary, even

with the same bolting material (e.g.
steel), according to the surface fin-
ish.

• Torque is greatly reduced when the

bolt and nut start turning together.

5) Socket play

Torque is lowered as the six-sided
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 pulled out.

7) Effect of Connecting Adapter

The tightening torque will be lowered
through the use of a universal joint or
a connecting adaptor.

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