Abstract: The invention relates to a drill for realizing a partially tapered bore hole in a soil covering a hardpan layer. The drill comprises a rotatable drivable unit that is provided with a carrying structure and a multiple number of cutting elements carried by the carrying structure. The multiple number of cutting elements are arranged along a line extending substantially radially and outwardly from a central axis of the rotatable drivable unit. Further, lower ends of cutting elements in a radial inner section are mainly positioned in a plane transversely to the rotation axis of the rotatable drivable unit. Lower ends of cutting elements in a radial outer section are mainly positioned in a downwardly tapered surface having a symmetry axis coinciding with the rotation axis of the rotatable drivable unit. The lower ends of the cutting elements may subscribe, during rotation, a truncated cone surface.

Abstract: The invention relates to a drill for realizing a partially tapered bore hole in a soil covering a hardpan layer. The drill comprises a rotatable drivable unit that is provided with a carrying structure and a multiple number of cutting elements carried by the carrying structure. The multiple number of cutting elements are arranged along a line extending substantially radially and outwardly from a central axis of the rotatable drivable unit. Further, lower ends of cutting elements in a radial inner section are mainly positioned in a plane transversely to the rotation axis of the rotatable drivable unit. Lower ends of cutting elements in a radial outer section are mainly positioned in a downwardly tapered surface having a symmetry axis coinciding with the rotation axis of the rotatable drivable unit. The lower ends of the cutting elements may subscribe, during rotation, a truncated cone surface.