Ring shafts.
Smooth shaft surface is more prone to encrustation. Therefore, on moderately compact soils, ring rollers are used. Such a shaft consists of smooth cast iron wedge rings, smooth or toothed. These rings may be loosely or firmly seated on the axis. Loosely fitted rings wear faster, but they do not stick to moist soil. These rollers crush the soil better than smooth rollers. Some of these shafts have sand or stone boxes to add weight to them.