A vibratory compactor includes a roller and an eccentric shaft. The roller is rotatably mounted on a main frame and may include a first vertical support and a second vertical support. The eccentric shaft is rotatably connected between the first vertical support and the second vertical support in the roller. The eccentric shaft includes a first end, a second end, a first eccentric weight, a second eccentric weight, and a center portion, casted as a single piece. The first eccentric weight is proximal to the first end and the second eccentric weight is proximal to the second end. The center portion may be disposed between the first eccentric weight and the second eccentric weight. The center portion may include at least one cavity on a surface of the center portion. The at least one cavity is elongated between the first eccentric weight and the second eccentric weight.