標準號：BS 3A 125 to 3A 132, 3A 136 to 3A 143, 3A 147 to 3
中文標準名稱：航天器用系緊螺母(統一螺紋)規范
英文標準名稱：Specification for stiffnuts (Unified threads) for aircraft
標準類型：V20
發布日期：1981/6/30 12:00:00
實施日期：1981/6/30 12:00:00
中國標準分類號：V20
國際標準分類號：49.030.30
適用范圍：1 These British Standards cover the dimensions, material, finish, testing and identification of aircraft stiffnuts with Unified threads. According to the materials used in their construction, the stiffnuts are classified as satisfactory for use at sustained tempera-tures within the following ranges: (a) -75 ℃ to +425 ℃: corrosion-resisting steel nuts, silver plated or unplated (b) -75 ℃ to +200 ℃: steel and corrosion-resisting steel nuts, cadmium plated (c) -75 ℃ to +125 ℃: aluminium alloy, brass or bronze nuts. NOTE. All nuts are capable of remaining effective for servicing operations at -40 ℃. 2 Stiffnuts of the following types are covered by these British Standards: (a) hexagon nuts: ordinary, thin and cap (b) anchor nuts: (1) double-lug fixed: ordinary, thin and cap (2) double-lug floating: ordinary and thin (3) single-lug fixed: ordinary and thin (c) stripnuts floating: ordinary and thin. 3 In these standards, the nut bodies, whether of normal hexagon form or not, have a thread strength as least as great as the corresponding standard nuts.