How much torque does it take to tighten a bolt?
Because torque at specific bolt tension varies by as much as +/-30%, even within a specific set set or lot of bolts, Torque tables are not allowed for structural bolts. If a torque value is to be established for a particular bolt grade and diameter, the Research Council rules are as follows: • Select a representative bolts/nut/washer set. Be sure to duplicate the condition of the bolt set, that is, weathered, rusted, new, long, short, etc. • Tighten it in a Skidmore to 1.05 times the minimum tension required (see bolt tension). • Do this three times. Average the results. • This torque value becomes the value to use for that shift, for that type of bolt set and condition. Remember, if any of the hardware or tightening conditions change, the torque setting must be recalibrated. Calibration of torque must be done every day without fail, or more often. If you would just like to estimate the torque (say, to pick a wrench capacity), a guestimated torque value can be determined from the simpl
