<div class="htmlview paragraph">A vibrating digger blade with one input to move the blade horizontally and one input to move the rear of the blade vertically was tested to determine a mode of vibration that would produce the most effect on the soil at acceptable torque and power inputs. A kinematic and dynamic simulation program which accounted for the frictional and inertial effects of the moving parts of the machine and a block of soil on the blade was written and used to help decide which independent parameters and their levels to use in a field test program. The optimum combination of elements yielded by the study for use in a commercial digger design was an eccentricity of 9.52 mm for horizontal movement, an eccentricity of 12.7 mm for vertical movement, and an operating velocity ratio of 1.0.^{<span class="xref">1</span>}</div>