OPERATION AND MAINTENANCE MANUAL | ENG_OMM_AlphaGrinder_P01 | 10th July 2019
© Pandrol 2020
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7. Mounting Torque for Screws & Nuts
The preload force must be maintained at a level where the tensile stress and the intensity of the torsional stress do
not exceed the screws yield stress for the specific material. Its main function is to clamp together the assembled
parts and produce friction force between the assembled parts.
At Pandrol AB we mainly use steel screws and nuts. The table below shows the nominal tightening torque in Nm
for the screws and nuts that are used
These torques do not apply to wheel bearings!
Table 5:
Thread diameter
[mm]
Tightening Torque (per bolt grade) [Nm]
Grade 8.8
Grade 10.9
Grade 12.9
5
5,7
8,1
9,7
6
9,8
14
17
8
24
33
40
10
47
65
79
12
81
114
136
14
128
181
217
16
197
277
333
18
275
386
463
20
385
541
649
22
518
728
874
24
665
935
1120
27
961
1350
1620
30
1310
1840
2210
33
1770
2480
2980
36
2280
3210
3850
IMPORTANT
Check that all bolts and nuts are tightened at least every 8 hours until 80 hours have been
reached. If necessary, use spanner to tighten.
