scope:

This standard specifies a tightening test for determining the coefficient of friction in the thread of bolt/nut assemblies under specified conditions. It is only applicable for comparison purposes, such as a comparison of assemblies with different surface finishes or for cases where different lubricants are used.

Application-oriented tightening tests relevant for determining the coefficient of friction in bolt/nut assemblies of specific structural units are not detailed in this standard, due to the complexity of requirements.

This standard applies for aerospace applications only.

DIN EN ISO 16047 applies for the general industry.

Given the variety of boundary conditions in service (e.g. resilience of bolted components, finish of washers), the results of testing in accordance with this standard do not permit conclusions to be drawn as to the behaviour of bolt/nut assemblies in a particular application, e.g. where such assemblies form part of structural configurations.

NOTE Besides the method of test described here, the coefficient of friction may also be determined by other measuring techniques, such as the measurement of length change of a screw or bolt after applying a tightening torque.