Torque Tightening Metric Screw Threaded Fasteners
|Publication Date:||1 July 2014|
This AIR supplies information on recommended assembly torque limits for tension type nuts and bolts of the materials and plating combinations given in Table 1.
In calculating the torque values in Table 2, the following assumptions have been made:
a. Threads and bearing surfaces are lubricated with MIL-L-7808 aircraft engine oil.
b. The torque is applied to the nut. If torque is to be applied to the bolt head, the induced load may be reduced by friction on the shank.
c. The tensile preload stress is 440MPa.
The purpose of this Aerospace Information Report (AIR) is to provide the aerospace propulsion industry with recommended assembly torque limits for threaded fasteners when a common torque value per fastener size is the objective. (The fasteners are based on the dimensional data in MA1518). It also provides a series of curves that show the effect of the coefficient of friction on the axial load produced in a fastener, when the recommended torques are applied.