The paper presents a dynamic model of a small electro-pneumatic percussive tool whose handle is elastically connected to the casing. The pneumatic force is defined as a function of the position of the piston and the striker. The Hertz model has been applied to the impact forces and given the conditions under which they exist. The differential equations define the movement of each part of the hammer. Their simulations show how the hammer parts vibrate, when the impacts occur, and how large the impact forces can be. The acceleration of the handle is determined and compared with the acceleration when the handle is part of the casing. The article proves that the hammer with a floating handle is better for the operator's protection.