An earlier percussive boring method used largely in Europe for exploration, etc. The cutting tool is given a rapid but very short stroke, and the hole is flushed by water passing down through the hollow rods. No beam is used, but the rope to which the boring tools are suspended has an up-and-down motion imparted to it by an eccentric. The arrangement gives up to 250 strokes/min with a stroke length as low as 3-1/4 in (8.3 cm).