2 General Information
2.1 Tightening specifications for screws, nuts and bolts
Tightening torques for setscrew and stud joints to MTN 5008 standard
This standard applies to setscrews not subject to dynamic loads and the associated nuts according to:
• MMN 384
• DIN 912
• ISO 4014 (DIN 931-1)
• ISO 4017 (DIN 933)
• EN 28765 (DIN 960)
• EN 28676 (DIN 961)
• DIN 6912
This standard applies to studs not subject to dynamic loads and the associated nuts according to:
• DIN 833
• DIN 835
• DIN 836
• DIN 938
• DIN 939
The standard does not apply to heat-resistant screws in the hot component zone.
Tightening torques M
A
are specified for screws of strength class 8.8 (surface finish bare metal, phosph-
atized or galvanized) and 10.9 (surface finish bare metal or phosphatized).
The values in the table are based on a friction coefficient µtot = 0.125.
Threads and mating faces of screws and nuts must be coated with engine oil prior to assembly.
When hand-tightening (defined torque), an assembly tolerance of +10% of the figures in the table is per-
mitted.
When machine-tightening, the permissible assembly tolerance is ±15%.
Thread
Hand-tightening
Machine-tightening
8.8 M
A
(Nm)
10.9 M
A
(Nm)
8.8 M
A
(Nm)
10.9 M
A
(Nm)
M6
9
12
8
11
M8
21
31
20
28
M8 x 1
23
32
21
30
M10
42
60
40
57
M10 x 1.25
45
63
42
60
M12
74
100
70
92
M12 x 1.25
80
110
75
105
M12 x 1.5
76
105
72
100
M14
115
160
110
150
M14 x 1.5
125
180
120
170
M16
180
250
170
235
M16 x 1.5
190
270
180
255
M18
250
350
240
330
M18 x 1.5
280
400
270
380
M20
350
500
330
475
M20 x 1.5
390
550
350
520
M015590/06E 2014-03
| General Information | 15
TIM-ID: 0000002333 - 015
