This British Standard gives the general dimensions and tolerances of black hexagon bolts, screws and nuts with ISO metric threads, in diameters from 5 mm to 68 mm inclusive. Mechanical properties are included for steel bolts, screws and ordinary plain nuts, which may be produced by hot or cold forging at the option of the manufacturer. Dimensional requirements are included for bolts, screws and nuts finished black all over and for those which have partially machined finishes. NOTE 1 The term “black” does not necessarily relate to the appearance of the products, since these may be of bright appearance or black in the finished state. The term implies the comparatively wider tolerances to which these products are usually made. NOTE 2 Nuts with an effective height of less than 0.6d or a width across flats or outside diameter of less than 1.45d, or both, are excluded from the mechanical requirements specified in this standard. NOTE 3 It is considered that the range of nominal sizes included in this standard is adequate for most of the applications for which this series is likely to be employed but, for the convenience of users requiring larger sizes, further information is provided in Annex C.
The following normative documents contain provisions which, through reference in this text, constitute
provisions of this British Standard. For dated references, subsequent amendments to or revisions of any of
these publications do not apply. For undated references, the latest edition of the publication referred to
applies.
BS 1916-1:1953, Limits and fits for engineering — Part 1: Limits and tolerances.
BS 3643-1:1981, ISO metric screw threads — Part 1: Principles and basic data.
BS 3643-2:1981, ISO metric screw threads — Part 2: Limits and tolerances for coarse pitch series
threads.
BS 3692:2001, ISO metric precision hexagon bolts, screws and nuts — Specification.
BS 7345:1990 (ISO R 888), Nominal lengths for bolts, screws and studs — Thread lengths for general
purpose bolts.
BS 7371-6:1998, Coatings on metal fasteners — Part 6: Specification for hot dipped galvanized
coatings.
BS EN ISO 4042:2000, Fasteners — Electroplated coatings.
BS EN 10002-1:1990, Tensile testing of metallic materials — Part 1: Method of test at ambient
temperature.
BS EN 10109-1:1996, Metallic materials — Hardness test — Part 1: Rockwell test (scales A, B, C, D, E, F,
G, H, K) and Rockwell superficial test (scales 15 N, 30 N, 45 N, 15 T, 30 T and 45 T).
BS EN 10109-2:1996, Metallic materials — Hardness test — Part 2: Verification of Rockwell hardness
testing machines (scales A, B, C, D, E, F, G, H, K, N, T).
BS EN 10109-3:1996, Metallic materials — Hardness test — Part 3: Calibration of standardized blocks to
be used for Rockwell hardness testing machines (scales A, B, C, D, E, F, G, H, K, N, T).
BS EN 20286-1:1993, ISO system of limits and fits — ISO system of limits and fits — Part 1: Specification
for uses of tolerances, deviations and fits.
BS EN 20286-2:1993, ISO system of limits and fits — ISO system of limits and fits — Part 2: Tables of
standard tolerance grades and limit deviations for holes and shafts.
BS EN 20898-2:1994, Mechanical properties of fasteners — Nuts with specified proof load values —
Coarse thread.
BS EN ISO 1234:1998, Split pins.
BS EN ISO 898-1, Mechanical properties of fasteners made of carbon steel and alloy steel —
Part 1: Bolts, screws and studs.
BS EN ISO 6506-1:1999, Metallic materials — Brinell hardness test — Part 1: Test method.
BS EN ISO 6506-2:1999, Metallic materials — Brinell hardness test — Part 2: Verification of Brinell
hardness testing machines.
BS EN ISO 6506-3:1999, Metallic materials — Brinell hardness test — Part 3: Calibration of reference
blocks.
BS EN ISO 6507-1:1998, Metallic materials — Vickers hardness test — Part 1: Test method.
BS EN ISO 6507-2:1998, Metallic materials — Vickers hardness test — Part 2: Verification of testing
machines.
BS EN ISO 6507-3:1998, Metallic materials — Vickers hardness test — Part 3: Calibration of reference
blocks.