Hitachi WH14DM OM Use a tightening time suitable for the screw, Bolt Steel plate Thickness t Nut

English

4.Use a tightening time suitable for the screw

The appropriate torque for a screw differs according to the material and size of the screw, and the material being screwed etc., so please use a tightening time suitable for the screw. In particular, if a long tightening time is used in the case of screws smaller than 5/16” (8 mm), there is a danger of the screw breaking, so please confirm the tightening time and the tightening torque beforehand.

Tightening torque

kgf•cm N•m

(in-lbs)

1600 160

(1390)

1400 140

(1218)

1200 120

(1042)

1000 100

(868)

80080

(695)

60060

(521)

40040

(347)

20020

(174)

0 0

3/8"×1-3/6"

(M10×30)

High strenge bolt

Ordinary bolt

0 1 2 3

kgf•cm		N•m			15/32"×1-3/4"				kgf•cm				N•m	9/16"×1-31/32"
					(M12×45)											(M14×50)
	(in-lbs)	160								(in-lbs)			160
	1600									1600				High strenge bolt
	(1390)									(1390)
	1400	140		High		strenge	bolt			1400		140
torque	(1218)								torque	(1218)
	1200	120								1200		120
	(1042)									(1042)
		100
Tightening	1000								Tightening	1000		100
	(868)									(868)
		80													Ordinary bolt
	800									800			80
	(695)				Ordinary bolt					(695)
	600	60								600		60
	(521)									(521)
	400	40								400		40
	(347)									(347)
	200	20								200		20
	(174)									(174)
	0	0								0		0
			0		1	2		3			0			1		2	3

Tightening time: sec

(Steel plate thickness t = 3/8" (10 mm))

Bolt	Steel plate
	thickness t

Nut

Tightening	time: sec	Tightening	time: sec
(Steel plate	thickness	(Steel plate	thickness
t = 1" (25 mm))		t = 1" (25 mm))

Fig. 15

*The following bolt is used. Ordinary bolt: Strength grade 4.8

High tensile bolt: Hardness division 12.9

(	Explanation of strength grade:
	4 — Yield point of bolt: 45,500 psi (32 kgf/mm2)
	8 — Pulling strength of bolt: 56,900 psi (40 kgf/mm2) )
	Fig. 16

19