General Information; Tightening Specifications For Screws, Nuts And Bolts - MTU 12V4000M73 series Operating Instructions Manual

2 General Information

2.1 Tightening specifications for screws, nuts and bolts

Tightening torques for setscrew and connections as per MTN 5008 standard
This standard applies to setscrews not subject to dynamic loads and the associated nuts according to:
• MMN 384
• ISO 4762 (DIN 912)
• ISO 4014 (DIN 931-1)
• ISO 4017 (DIN 933)
• DIN EN ISO 8765 (EN 28765; DIN 960)
• DIN EN ISO 8676 (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 EN ISO 5395 (DIN 836)
• DIN 938
• DIN 939
This standard applies to screws with hexalobular heads according to:
• DIN 34800
• DIN 34801
The standard does not apply to heat-resistant screws in the hot component zone.
Tightening torques M
galvanized) and 10.9 (surface condition bare 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 -5+15% of the figures in the table is permit-
ted.
When machine-tightening, the permissible assembly tolerance is ±15%.
Tightening torques for setscrews
M6
M8
M8 x 1
M10
M10 x 1.25
M12
M12 x 1.25
M12 x 1.5
M14
M14 x 1.5
M16
M16 x 1.5
20 | General Information | MS150045/03E 2018-08
are specified for screws of strength class 8.8 (surface condition bare, phosphatized or
A
Thread
8.8 M
Hand-tightening
(Nm) 10.9 M (Nm)
A A
9 12
21 31
23 32
42 60
45 63
74 100
80 110
76 105
115 160
125 180
180 250
190 270
Machine-tightening
8.8 M (Nm) 10.9 M
A
8 11
20 28
21 30
40 57
42 60
70 92
75 105
72 100
110 150
120 170
170 235
180 255
(Nm)
A