Patent ID: 7357200

Claim:
An earth drilling device comprising: a center shank having an imaginary central axis, said shank presenting an earth penetrating end; a flight wound about said shank, a portion of said flight helically extending between said earth penetrating end and an upstream position longitudinally displaced along said shank axis from said earth penetrating end and radially displaced from said shank axis at a distance approximating a desired radius of a hole to be drilled upon operation of the device; a plurality of housings along said portion of said flight beginning adjacent said earth penetrating end, each housing presenting a cutting tooth having a configuration presenting a cutting path of a primary width, said plurality of housings with a respective tooth therein positioned along said flight portion to define a plurality of successively adjacent teeth corresponding to a plurality of adjacent cutting paths helically wound about said shank axis between said earth penetrating end and said upstream position, each successively adjacent tooth of said plurality of teeth beginning at said shank end being radially displaced at successively increasing radial distances from said shank axis and longitudinally displaced from said shank end at successively increasing longitudinal distances, said radial distances resulting in cutting paths of adjacent teeth at least contiguous to preclude gaps between said cutting paths, one of said teeth being positioned approximate said desired radius distance from said axis, a portion of said flight subsequent to said housings presenting an earth cutting edge, whereby to form a flight having a first cutting portion defined by said helical teeth and a subsequent cutting portion defined by said subsequent cutting edge.