scope:

Tapping screws covered by this specification are classified as thread-forming screws, thread-cutting screws, and drive screws. The thread-forming screws are further classified as sheet-metal screws, designated types A,B, and BP, and machine screws, designated type BP a cone point, and types B and C a blunt point with crests of the and threads tapered. Thread-cutting screws are substantially the same as blunt-point thread-forming screws except that the ends are modified to have cutting edges. The type designations of thread-cutting edges. The type designations of thread-cutting screws, which are used in this soecufucatuibm are combinations of the above letters and another letter, as S, designating slotted ends; G, designating grooved ends with large chip-clearance cavities; and F, designating fluid ends. Commercial designations differ from these as shown in 6.3. Drive screws have multiple threads of large lead angle and are designated as type U drive screws.