How a Tiller Works
A power tiller is basically a set of blades (called tines) that are mounted within a wheeled housing and are powered by either a gasoline engine or an electric motor. Each tine consists of four blades curving in alternately opposing directions. Blades one and three are curved pointing in toward the tiller; blades two and four are curved pointing away from the tiller. The inward-pointing tines keep the clods of soil and grass from accumulating on the blades, while the outward-pointing tines are the heavy cutters. They all work in conjunction with one another to dig into the soil aggressively, all the while moving soil away from the tines to avoid clogging them.