BS 4882

Nuts for use with inch series studbolts and studs

Dimension
Nuts shall comply with the dimension and tolerances given in table 22 or 23.
Note: Nuts of the followinggrades(see table 4) should be supplied as heavy series (see table 22)
unless the purchaser requests the normal series: 2H   4   L4   7   8C   8T

Faces

Heavy series nuts (see table 22) and normal series nuts (see table 23) shall have a chamfer of approximately 30° on the non-bearing face.
The bearing face shall be finished with either a washer face or a chamfer of approximately 30°.

The bearing face shall be machined or have a surface finish equal to that produced by machining.

The face of the nut hsall be square to the axis of the thread of the nut within the tolerances given in table 22 and 23(see figure 6 and 7) when tested as described in appendix E.

Screw thread

Screw threads shall be ISO inch (UNC) for sizes up to and including 1 in diameter and 8 threads/in (8 UN series) for sizes 1 1⁄8 in diameter and above in accordance with BS 1580 and shall conform to the tolerances for class 2B specified in that standard.
NOTE. See Item (d) (6) of appendix C.
The screw threads of nuts shall be concentric with the hexagon within a tolerance of 2 IT13, FIM, using the width across the flats as the reference datum.