This SAE Recommended Practice defines, illustrates, and specifies allowable limits for the various types of surface discontinuities that may occur during the manufacture and processing of metric-series nuts, in sizes 6.3 to 25 mm and inch-series nuts in sizes 1/4 to 1 in., inclusive, which are primarily intended for use in automotive assemblies.

The basic recommended practice does not include inspection sampling requirements. It is intended that the purchaser shall specify in the original inquiry and purchase order the inspection sampling requirements which the producer must satisfy to demonstrate the acceptability of nuts with respect to surface discontinuities. Appendix A outlines inspection sampling plans applicable when such requirements are not specified by the purchaser in the original inquiry and purchase order.