Flat-stroke electric drill itself has only the force of rotation, while impact electric drill (electric hammer) has a force of axial vibration besides the force of rotation. Electric drills can drill holes in various metals, wood, plastics and other materials. Because of the hard and brittle characteristics of stones, bricks and concrete and the strong wear and tear of metal drills, it is necessary to use impact electric drills (electric hammers) to drill holes in these materials. The drills of electric hammers are embedded with high hardness cemented carbide, and the impact and rotation of impact electric drills (just like drilling holes on rocks with steel drills) are used to drill holes. In that way, as you beat and turn, the stone will be cut and ground bit by bit into a hole. If ordinary electric drill is used to drill holes in stone or concrete, the edge of ordinary drill is quickly worn out. The purpose of impact and rotation is to improve the efficiency of drilling.