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.
For best results, the draft angles (front frame) on the front harrow should be approximately level when the harrow is hitched to the tractor. If necessary, adjust tractor draw bar to obtain this result. In practically all field work the gangs should run level and cut at an even depth. Adjust the front harrow gangs to suit by raising or lowering the pressure plate at center of front harrow frame. The rear gangs may be leveled by raising or lowering the outer draw bar pressure plates. If the harrow ridges the soil between the rear gangs, the soil may be leveled by raising the inner end of the gangs, or by giving them less angle by moving the rear harrow frame forward at the three holes in the inner draw bars.