1.1 Scope. This inch series standard covers requirements for steel, self-drilling, tapping screws suitable for use in general engineering applications.

The objective of this standard is to ensure that self-drilling tapping screws, by meeting the mechanical and performance requirements specified, 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.

NOTE: The performance requirements covered in this standard apply only to the combination of laboratory conditions described in the testing procedures. If other conditions are met in an actual service application (such as different materials, thicknesses, etc.) drilling speed, drill load, starting torque, failure torque, and driving time values may require adjustment.

1.2 Designation. The two types of self-drilling tapping screws for which characteristics are covered in this standard are designated Types BSD and CSD.

1.2.1 BSD. BSD screws have spaced threads and are available with drill points of varying configuration, designated Style 2 and Style 3, designed to accommodate different panel thickness conditions as outlined in Table 6.

1.2.2 CSD. CSD screws have threads of machine screw diameter-pitch combinations approximating Unified form. CSD screws are not subject to thread gaging but shall meet the dimensional requirements of this standard. CSD screws are available with drill points of varying configuration, designated Style 2 and Style 3, designed to accommodate different panel thickness conditions as outlined in Table 6.