Almost always, a hammer drill is used for boring a hole in concrete. This is accomlished in conjunction with a carbide- tipped drilll bit. Carbide being VERY hard,will pulverize the cement and rock in the concrete when the Hammer stroke of the drill drives the bit against it. The rotating of the bit is used to draw the fragmented concrete out of the hole. SOME hammer drills can turn off the rotating of the drill bit, at which time you could place a chisel bit in the drill and have a power chisel. Most hammer drills can be set to: 1. rotate only,. 2. rotate and hammer at the same time. 3. Rarely, a hammer drill will have a hammer only setting.