Drill bit and cutting head for drill bit

摘要

A cutting head for a drill bit comprises four substantially identically shaped cutting arms extending radially from a common central axial point, each cutting arm comprising a cutting edge extending, outwardly and axially backwards from the common central axial point. The cutting edges are equianguiarly spaced apart from each other about the central axis of the cutting head. Each cutting, arm further comprises a side chamfer extending between its radially outer face and its rotationally trailing side face.

主权项

1. A cutting head. for a drill bit, the cutting head comprising:
a front end portion centered on a central axis of the cutting head; and at least four substantially identically shaped cutting arms extending radially outward from the front end portion a substantially identical radial distance from the central axis, and being substantially equiangularly spaced apart from each other about the central axis, each cutting arm including
a cutting edge extending generally radially outward from the front end portion,a radially outer face extending generally axially rearward from a radially outermost end of the cutting edge,a leading face extending generally radially outward from, the front end portion and generally axially rearward of the cutting edge, and facing a rotational drilling direction of the cutting head,a trailing face extending generally radially outward from the front end portion and generally axially rearward of the cutting edge, and facing away from the rotational drilling direction of the cutting head, anda side chamfer surface extending at an angle between the radially outer face and the trailing face.