Small to mid-sized disc-harrows are a most useful tillage implement. Some farmers consider them indispensable. Discs such as the McD 10-A may be used with either tractors or big hitches of work horses. This tool will cut both plowed and unplowed ground. Ahead of the moldboard plow, the disc harrow is a valuable tool to cut up and free tough sod. When employed in tandem with spring tooth harrows, a great deal of work can be accomplished in much less time.