This International Standard specifies the dimensions of bihexagonal nuts with counterbore and MJ threads and a self-locking feature achieved by forming the upper portion out-of-round, for classifications: 1100 MPa¹⁾/425 °C²⁾, 1100 MPa¹⁾/650 °C²⁾, 1210 MPa¹⁾/425 °C²⁾, 1210 MPa¹⁾/730 °C²⁾, 1550 MPa¹⁾/235 °C²⁾, 1550 MPa¹⁾/425 °C²⁾and 1550 MPa¹⁾/600 °C²⁾.

This International Standard is only applicable for the compilation of aerospace product standards.

1) Corresponds to the minimum tensile stress which the nut is able to withstand at ambient temperature without breaking or cracking when tested with a bolt of a higher strength class.

2) Maximum temperature that the nut is able to withstand, without permanent alteration to its original characteristics, after ambient temperature has been restored. The maximum temperature is conditioned by the material or by the surface treatment.