This British Standard specifies the coatings, dimensions, materials, lubrication and performance requirements for prevailing torque type bolts, screws and studs, with non-metallic prevailing torque elements incorporated into the thread, when tested at an ambient room temperature between 15 ℃ and 30 ℃.
It applies to bolts, screws and studs:
a) with ISO metric coarse pitch M4 to M24 threads in conformance with BS 3643 : Part 2 : 1981;
b) with specific strength requirements conforming to either BS 6104 : Part 3 : 1981, BS 6105 : 1981 or BS EN 20898-1 : 1992 as appropriate;
c) with threads of tolerance class 6g or 4h in conformance with BS 3643 : Part 2 : 1981;
d) for application into a mating component with a thread of tolerance class 6H in conformance with BS 3643 : Part 2 : 1981;
e) for use within the temperature range - 50 ℃ to +120 ℃;
f) with specific torque/clamping force requirements in conformance with BS 7371 : Part 2 : 1993.
The torque/clamping force requirements do not apply to set screws and similar threaded fasteners with physical properties in conformance with BS 6104 : Part 3 : 1981.
NOTE 1. Capability to provide a pressure or liquid seal is not within the requirements of this standard.
NOTE 2. Performance at temperatures outside the operating range is not within the requirements of this standard.
NOTE 3. Performance of bolts, screws and studs for which a lubricated coating is not permissible is not within the requirements of this standard.