1. Field of the Invention
The present invention is directed in general to drill bits and boring equipment, and more particularly to a drill bit apparatus and corresponding method of manufacturing the same.
2. Background Art
Drill bits have long been used in the machining and building arts. Generally, drill bits have surfaces which engage and remove material from a workpiece, thereby creating a workpiece bore. Self-feeding drill bits, as opposed to most spade bits or auger bits, are generally preferred because they cut workpiece bores faster, require less axial force to operate, and can produce workpiece bores which have larger diameters. However, conventional self-feeding drill bits fail to produce smooth workpiece bores. Further, many conventional self-feeding drill bits chip the surface of the workpiece which remains. In other words, most conventional self-feeding drill bits cause chipping of the workpiece surface outside the circumference of the workpiece bore as the drill bit enters the workpiece.
While most drill bits are used to bore a workpiece bore which extends through the surface of the workpiece, drill bits can also be used to bore a cavity into a workpiece. In such a case, most conventional self-feeding drill bits are inadequate because after the drill bit is withdrawn, uncut material remains at the bottom of the cavity. In particular, as most self-feeding drill bits include self-feeding subassemblies for drawing the drill bit into the workpiece. Such subassemblies typically comprise a screw which protrudes from the top-center portion of the drill bit. However, most conventional self-feeding drill bits are inadequate for producing cavities, because when the drill bit is withdrawn from the cavity, uncut material typically remains around the hole created by the screw. Therefore, such conventional drill bits produce cavities having an unsuitable finish.
Therefore, it is a first object of the present invention to provide a substantially self-feeding cutting apparatus adapted to produce a bore and/or a cavity in a workpiece.
It is a second object of the present invention to provide a cutting apparatus having a low manufacturing cost and low production cost.
It is a further object of the present invention to provide a cutting apparatus which exhibits extended durability, thereby minimizing tooling downtime.
Yet another object of the present invention is to provide a cutting apparatus having a drill bit head removably secured to a shaft.
Another object of the present invention is to provide a cutting head that can maintain the sharpness of the cutting edges, so that chip formation can be properly controlled, and so that the bore surfaces can be of suitable surface finish.
A further object of the present invention is to provide a cutting head having two cutting vanes, each vane having two cutting edges which are substantially perpendicular to each other.
A further object of the present invention is to provide a channel for efficiently expelling chips formed during the drilling operation.
Yet another object of the present invention is to provide a grasping assembly having substantially flat faces to be used when securing the drill bit head to the shaft.
Another object of the present invention is to provide cutting edges which are adapted to produce a cavity wherein all of the surfaces are of a suitable surface finish.
The above-listed objects are met or exceeded by the present drill bit for producing workpiece bores. The drill bit is composed of a drill bit head and shaft. The drill bit head includes a drill bit cutting head and a guide point. The drill bit cutting head includes a first and a second cutting vane, and opposing surfaces for grasping and rotating the drill bit cutting head about the axis of rotation of the drill bit, thereby securing the drill bit head to the shaft.
Each cutting vane includes a first cutting edge which extends perpendicular to the axis of rotation and is provided for removing workpiece material, a second cutting edge which extends parallel to the axis of rotation and is provided for forming a substantially smooth workpiece bore, and a channel for facilitating the expulsion of removed workpiece material away from the first cutting surface as the drill bit passes through the workpiece.