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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
 ABCDEFGHI
1Washer sizeBolt sizePitch
[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]
3NLX6M61,0139,7129,7128,0
4NLX8M81,25321829182915
5NLX10M101,5622857285623
6NLX12M121,751074099409733
7NLX14M142,0170551575515546
8NLX16M162,0260752407523762
9NLX20M202,551011847011846497
 ABCDEFG
1Washer sizeBolt sizePitch
[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]
3NLX6M61,015,512,915,513,6
4NLX8M81,2537233725
5NLX10M101,573377339
6NLX12M121,751265412657
7NLX14M142,02017420178
8NLX16M162,0307100306106
9NLX20M202,5602156600165
 ABCDEFG
1Washer sizeBolt sizePitch
[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]
3NLX6M61,017,415,41816,3
4NLX8M81,2542284330
5NLX10M101,582448547
6NLX12M121,751426514668
7NLX14M142,02268923394
8NLX16M162,0345120355127
9NLX20M202,5676188696198