SWORD DRILL BACKGROUND OF THE INVENTION Field of the Invention The present invention relates generally to a sword drill, and more particularly to a sword drill having the ability to drill as well as reaming or countersink a hole simultaneously. BACKGROUND AND COMPENDIUM OF THE INVENTION There are many circumstances in the manufacturing industries that require the task of drilling a hole while leaving the hole somewhat sub-diessed and then following the drilling operation with a second operation with a countersink to size the hole in desired size. The number of operations required to manufacture a piece is directly related to the cost of the piece. In this way, it is convenient to provide a drill with the ability to drill as well as countersink a hole simultaneously. Accordingly, the sword drill of the present invention has the ability to drill as well as countersink a hole simultaneously, thereby eliminating the requirement for a second countersink operation, after a hole is drilled. The sword bit includes a V-shaped drill cut and a pair of countersunk edges on each side. The countersink edges have a relatively large radius of curvature and generally define a flat portion at the apex of the countersunk edges. Additional areas of applicability of the present invention will be apparent from the detailed description provided herein. It should be understood, however, that the detailed description and specific examples while indicating preferred embodiments of the invention are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will be apparent to those skilled in the art. specialty from this detailed description. DESCRIPTION OF THE DRAWINGS The present invention will be more fully understood from the detailed description and accompanying drawings, wherein: Figure 1 is a side view of the sword bit according to the principles of the present invention illustrating the radius of lack of correspondence or tangentization (miss-blended) between the drill section and the sides; Figure 2 is a side view of the sword drill shown in Figure 1, illustrating the countersink radius;
Figure 3 is a side view of the sword drill shown in Figure 1, illustrating the flat portions in each countersink section; and Figures 4A and 4B are side and end views respectively of the tool holder for holding the sword drill according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED MODALITIES With reference to Figures 1 to 4B, the sword drill of the present invention will be described. The sword bit 10 includes a drill cut end in the generally V 12 shape, with a first cutting edge 14 and a second cutting edge 16 on opposite sides of the sword bit. In the outer diameter of the cutting edges 14, 16, each opposite side 18 has a radius 20 which is not tangent to the cutting edge 14, 16 or the side diameter of the drill portion and thus lack of correspondence or tangential (miss-blended) on both portions of the cutting edge 14, 16 and on the sides 18. This miss-blended radius 20 has two purposes: (1) it provides the centering effect of the bit conforming the drill enters the workpiece in its rotational mode; and (2) provides gradual wear or a barrier to prolong the natural wear and tear that occurs as the drill undergoes normal wear and tear. Compared to other forms such as the tangent radius or integral, or angular edge, the outer edge tends to be deposited or broken causing the hole to become unbalanced, as well as unable to maintain its indicated triangular reading that is required to produce the self-centering effect . This also causes the diameter to be affected dimensionally, therefore causing premature failure of the tool. As illustrated in Figure 3, the sides 18 of the spade bit have a countersink feature, which includes a large radius "R" on opposite sides 18 of the spade bit that does not exhibit "mismatch (miss-blended). ) "tangent to the cutting edges 14, 16 of the drill section 12 and the trailing edge. The sides 18 perpendicular to the drill cut face 12 have a flat part 22 in the center of the most distant diametral point remote from the radius "R". The radius "R" shown is greater than a width of the sword bit 10. As is commonly known in the countersinking technique, a countersink must be allowed to pass through a hole that is smaller in diameter than the Countersink device size. This in turn creates a cleaning action or a polishing effect, which creates the required hole size. As illustrated in Figure 3, the back side sections 18 are identical in design where the non-tangent radius "R" of the sides 18 expands the pre-drilled hole for orifice expansion by a distance X shown in the Figure 2. Since the radius portion of the sides is not tangent, this provides a self-centering device. The identical planes 22 that are provided on opposite sides 18, in effect act as cleaners to polish the entire diameter. The length of the flat parts is determined by the speed of rotational versus linear insertion. The determining factor for the length of the flat parts 22 is that the rotation of the spade bit 10 is related to the down feed so that the rotating flat parts 22 transpose as they are fed in a downward or upward direction, effectively countersunk the diameter of the hole. It should be noted that the sides 18 have a radiated portion 24, 26 on each side of the flat portions 22, such that the spade bit provides a countersink function both when inserting and removing the spade bit 10 from the hole that has been cut. boring. The sword drill 10 of the present invention is mounted on a support 30 as illustrated in Figure 4 which is provided with a V-shaped cavity, to receive the V-shaped base 32 of the sword drill 10.
ytgt sword drill 10 is attached to the support by a pair of threaded fasteners 34, which are inserted from opposite sides of the tool holder 30. Cooling passages 36 are provided in the tool holder to blow coolant into the drilling contact surface . The coolant passages also provide the function of assisting in removing metal fragments that are removed from the workpiece. The screws 34 that are inserted through holes 37 of the spade bit 10, have a head portion 38 that abuts butt directly against a recessed seat portion 39, which surrounds the holes 37 of the spade bit 10 and a threaded portion 40 which extends in a head section 42 of the tool holder 30. With this design, the threaded head 38 does not interfere with the removal of the metal fragments that are removed by the 10 shank bit insert through of the fluted section 44 of the tool holder 30. Additional areas of applicability of the present invention will be apparent from the detailed description provided herein. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will be apparent to those skilled in the art. the specialty from this detailed description.