Method of controlling impact force and shock interval at a drop hammer of the type which has a core (10) and a number of casings (12, 14, 16, 19) arranged concentrically around the core. Between the core and the casings, spacings are arranged, and the core and the casings are interconnected alternatingly at one end and the other beginning at the upper end of the core. Between the lower end of the core and those ends of one or more casings, which are not permanently connected, a shock wave transferring connection is provided to short-circuit the path of the shock wave through the core and the casings.