scope:

This standard covers materials and performance requirements for metric and customary series case hardened self-drilling tapping screws suitable for general applications. It is applicable also to sems employing the respective types of tapping screws. Dimensional characteristics of the products on which this standard is based are shown in Appendix A.

CAUTION: Case hardened fasteners may be subject to delayed brittle fracture caused by hydrogen resulting from corrosion. Small a mounts of water, such as condense from humid air, can cause this type of failure particularly in the presence of anodic surface coatings, such as zinc or cadmium plate. Consequently, it is recommended that case hardened fasteners not be used in structural applications.

The objective of this specification is to insure that self-drilling tapping screws, by meeting the requirements specified herein, shall drill a hole and form or cut mating threads in materials into which they are driven without deforming their own thread and without breaking during assembly or service.