Self-tapping screws are usually drilled into pre-made holes (pilot holes) in metals, such as zinc, aluminum, and bronze and its alloys, as well as plastics and resin-impregnated plywood. They create ...

The basic tapping screws are classified as thread forming and thread cutting. Thread-forming tapping screws displace the material adjacent to the pilot hole so it flows around the screw threads.

A cheap and effective ratcheting tap. Need to cut threads into a hole? A tool called a tap is what you need, and a hand-operated one like the one shown here to the side is both economical and ...