The drill of the present invention has only one cutting discharge groove (11) formed in the outer periphery of a bit (10). A leading edge protruding farthest towards the tip in the axial direction in a tip flank (12) is composed at a single point and located on an axis (O). When bit is viewed from the tip side in the direction of axis, tip flank is in the form of a multilevel surface composed of second through fourth flanks (14B, 14C and 14D) arranged along the peripheral direction, and a reverse side first flank (14E) surrounded by second through fourth flanks and intersecting with axis.

A drill bit for boring non-linear holes in a workpiece, the drill bit having a generally elongate post, for mounting the drill bit to a tool; a generally elongate shank; and a head. The head has a front portion, a rear portion and there between a main body portion. A plurality of flutes are arranged in a generally helical shape along the main body portion, arched with respect to a longitudinal direction of the drill bit, each flute having an outer cutting edge arranged on an outside edge of the flute, to provide cutting capability in a direction substantially sideways compared to the longitudinal direction of the drill bit. A central point, arranged on the front portion of the head, is connected to at least one flute via a tapered first cutting portion, the first cutting portion being provided with a first cutting edge, to provide cutting capability in a direction substantially forwards. A forward facing roughing part is arranged on at least one flute and on the front portion of the head, the roughing part having a roughing edge, to provide further cutting capability in a direction substantially forwards. The rear portion of the head is connected to at least one flute via a tapered second cutting portion, the second cutting portion being provided with a second cutting edge, to provide cutting capability in a direction substantially rearwards.

Boring bits and methods for manufacturing boring bits. The method includes the acts of forming a shank including one end connectable to a power tool and an opposite end, molding a cutting head separate from the shank, the cutting head including a base wall and a side wall extending from the base wall, the base wall having an interior base surface and an exterior base surface, and bonding the shank and the cutting head as a unit including bonding the opposite end of the shank to the exterior base surface.