BS A 319:1997

Nuts, hexagonal, plain, reduced height, reduced across flats, with MJ threads, classifications: 450 MPa (at ambient temperature)/425°C, 600 MPa (at ambient temperature)/235°C, 600 MPa (at ambient temperature)/315°C, 600 MPa (at ambient temperature)/650°C, 900 MPa (at ambient temperature)/235°C, 900 MPa (at ambient temperature)/730°C and 1100 MPa (at ambient temperature)/600°C. Dimensions