Tightening Bolts And Nuts - Hardi NK SB Series Instruction Book

6 - Maintenance

Tightening Bolts and Nuts

When tightening bolts and nuts as a part of periodic service or due to replacement of spare parts, it is important to apply
the correct torque. This will prevent accidents and prolong the lifetime of the parts included in the bolted joints.
If not otherwise stated in this book, please tighten bolts and nuts using the following torques.
Bolt size Recommended
torque (Nm)
M4 2.4
M5 5
M6 8
M8 20
M10 39
M12 70
M14 112
M16 180
M18 240
M20 350
M22 490
M24 600
M27 976
M30 1300
±
WARNING! Applying too little torque will result in these risks:
• bolted joints will rattle and thus fail under fatigue
• bolts are being worn quickly and thus will not fulfil their design purpose
• bolted joints will come loose
• accidents caused by assembled parts coming apart due to bolts or nuts failing or falling off.
±
WARNING! Exceeding the maximum torque will result in these risks:
• damaging or stripping the threads and deforming the fastener
• bolt heads will be broken
• bolted joints will come loose
• accidents caused by assembled parts coming apart due to bolts breaking at a later time.
90
Maximum
torque (Nm)
3
6
10
25
50
85
140
215
305
435
590
750
1100
1495