In preparing this guide to torque values the following basic assumptions have been made: Bolts and nuts are new, standard finish, uncoated and not lubricated* The information supplied here is an acceptable guide for normal conditions and includes information on:
* If lubrication has been applied to the bolt and/or the nut (other than the 
Surface condition of bolt 

Self 
Electroplated 

Zinc 
Cadmium 
Phosphate 

Surface 
Self 
1,00 
1,00 
0,80 
0,90 
Zinc 
1,15 
1,20 
1,35 
1,15 

Cadmium 
0,85 
0,90 
1,20 
1,00 

Phosphate and oil 
0,70 
0,65 
0,70 
0,75 

Zinc and Wax 
0,60 
0,55 
0,65 
0,55 
Torque lbf.ft x 1.36 = N•m N•m x 0.737 = lbf.ft Force Pressure 
Flow l/s x 2.119 = cu.ft/min cu.ft/min x 0.472 = l/s Power

Imperial M = torque lbf.ft

Metric M = torque N•m

M2 = M1x 
L2 
L1 
where L1 in the normal length and L2 is the extended length, M1 is the set torque and M2
the actual torque applied to the nut.
eg. L1=500 L2=650 so
M2=100x  650  =130N•m 
500 
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