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Nord-Lock X-series washers: Torque guidelines

The figures are based on tests with calibrated torque transmitters and load cells performed in our laboratory. Thread friction coefficients have theoretical values but are verified through testing. Under head friction coefficients have been established by tests. The below values are to be considered as recommended nominal values to maximize the preload achieved in joints secured with Nord-Lock X-series washers.

 

Should you require torque guidelines for other bolt grades, sizes or materials, we will be able to support you. Please email technical.center@nord-lock.com or go to Contact us to find your local Nord-Lock office or authorized distributor.

 

Cu/C paste* = Copper/graphite paste (Molykote® 1000)
GF = Ratio of yield point. When tightening according to guidelines and with no deviation, this is the pre-stress achieved expressed as % of yield point.
μth = thread friction coefficient
μh = under head friction coefficient
1 N = 0,225 lb
1 Nm = 0,738 ft-lb

Units: Metric UNC
  A B C D E F G H I
1 Washer size Bolt size Pitch
[mm]
Oil, GF=75%
µth=0,15, µh=0,19
Cu/C paste*, GF=75%
µth=0,13, µh=0,18
Dry, GF=62%
µth=0,18, µh=0,2
2       Torque
[Nm]
Clamp load
[kN]
Torque
[Nm]
Clamp load
[kN]
Torque
[Nm]
Clamp load
[kN]
3 NLX6 M6 1,0 13 9,7 12 9,7 12 8,0
4 NLX8 M8 1,25 32 18 29 18 29 15
5 NLX10 M10 1,5 62 28 57 28 56 23
6 NLX12 M12 1,75 107 40 99 40 97 33
7 NLX14 M14 2,0 170 55 157 55 155 46
8 NLX16 M16 2,0 260 75 240 75 237 62
9 NLX20 M20 2,5 510 118 470 118 464 97
  A B C D E F G
1 Washer size Bolt size Pitch
[mm]
Oil, GF=71%
µth=0,15, µh=0,15
Cu/C paste*, GF=75%
µth=0,13, µh=0,15
2       Torque
[Nm]
Clamp load
[kN]
Torque
[Nm]
Clamp load
[kN]
3 NLX6 M6 1,0 15,5 12,9 15,5 13,6
4 NLX8 M8 1,25 37 23 37 25
5 NLX10 M10 1,5 73 37 73 39
6 NLX12 M12 1,75 126 54 126 57
7 NLX14 M14 2,0 201 74 201 78
8 NLX16 M16 2,0 307 100 306 106
9 NLX20 M20 2,5 602 156 600 165
  A B C D E F G
1 Washer size Bolt size Pitch
[mm]
Oil, GF=71%
µth=0,15, µh=0,13
Cu/C paste*, GF=75%
µth=0,13, µh=0,14
2       Torque
[Nm]
Clamp load
[kN]
Torque
[Nm]
Clamp load
[kN]
3 NLX6 M6 1,0 17,4 15,4 18 16,3
4 NLX8 M8 1,25 42 28 43 30
5 NLX10 M10 1,5 82 44 85 47
6 NLX12 M12 1,75 142 65 146 68
7 NLX14 M14 2,0 226 89 233 94
8 NLX16 M16 2,0 345 120 355 127
9 NLX20 M20 2,5 676 188 696 198