Panasonic EY7270 Factors Affecting Tightening Torque, Bolt Tightening Conditions, Tightening time

Factors Affecting

Tightening Torque

The tightening torque is affected by a wide variety of factors including the following. 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.

Bolt Tightening Conditions

	N • m		(EY7271 only)
	(kgf-cm)	M10, M12, M14, M16 Standard bolt
	165
	(1683)		M16
	140
	(1428)
	120		M14
torque	(1224)
	(1020)
Tightening	100		M12
	60
			M10
	80
	(816)
	(612)
	40
	(408)
	20
	(204)
		12	3
			Tightening time (Sec.)

	N • m		(EY7271 only)
	(kgf-cm)	M8, M10, M12, M14 High tensile bolt
	165
	(1683)		M14
	140
	(1428)		M12
	120
torque	(1224)
	(1020)
Tightening	100		M10
	60
	80
	(816)
	(612)		M8
	40
	(408)
	20
	(204)
		12	3
			Tightening time (Sec.)
	Bolt		Washer
			Steel plate
			thickness 10 mm (3/8")
	Nut		Washer
			Spring washer

Tightening conditions

*The following bolts are used. Standard bolts: Strength type 6.8 High tensile type 12.9 Explanation of the strength type

Bolt yield point

(80% of tensile strength)

48 kgf/mm2 (68000 psi)

Bolt tensile strength 60 kgf/mm2 (85000 psi)

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 affects the tightening torque.

Generally, as the bolt diameter

increases, tightening torque rises.

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2006/05/25 13:25:06