Self drilling screw，the screw is a tool for fastening the machine parts step by step by using the physics and mathematics principles of the circular rotation of the inclined plane and friction. The drilling screw is a screw with a self-tapping drilling head at its front end. Screw is a common invention in people's production and life for thousands of years. According to the application field, it is the first great invention of mankind. Drilling screw is a new invention in recent years, also called self-drilling screw.
