As Type A self-tapping screws feature a coarse thread, they can easily self-start their own hole in the metal, wood, plastic, or other thin substrate material. Type A self-tapping screws and Type AB self-tapping screws are also known as Sheet Metal Screws.
Type A self-tapping screws have coarse threads that make them useful when you need to drill or nest a hole in thin sheet metal, resin plywood, asbestos combinations and other materials. They are threading screws and not recommended for new designs.
Type A sheet metal screws have wider spaced threads for self-starting in thinner metal or plywood. Type AB sheet metal screws have more threads per inch and are more effective in brittle materials than Type A.
