BS A 31-54. Specification for British Association (B.A.) low tensile screws and nuts for aeronautical purposes|Nuts, Screws (bolts), Threaded fasteners, Internal-thread fasteners, External-thread fasteners, Threaded components, Cheese-head fasteners, Round-head fasteners, Countersunk fasteners, Raised-head fasteners, British Association screw threads, Aircraft components, Air transport engineering, Hexagonal-head fasteners, Locknuts, Vibration-resistant fasteners, Low-carbon steels, Stainless steels, Aluminium alloys, Brass, Protective coatings, Dimensions, Points (fasteners), Fasteners, Close-fit threads, Threads, Designations