fig4 the profile of the lower portion 26 b has an inwardly angled portion 26 b u2032 and an outwardly angled portion 26 b u2033 however it is understood that the invention is not so limited for example in one alternate embodiment the lower portion 26 b is faceted such that the leading edge of lower portion 26 b is curved in one preferred embodiment the inside edge 48 of blade 30 is angled relative to the vertical axis 46 at angle of approximately 25 degrees but it is understood that the blade 30 could be formed to extend at other angles however it is generally preferred that the angle u03b1 be between approximately 15 degrees and approximately 60 degrees blade 32 is angled relative the vertical axis as defined by its inner edge 50 at a preferred angle u03b2 of 30 degrees but it is understood that the blade 32 could be formed to be angled at other angles however it is generally preferred that the angle u03b2 be between approximately 15 degrees and approximately 60 degrees referring now to fig4 in addition to its flared orientation shanks 30 and 32 are also biased in a forward direction and a rearward direction respectively more particularly the backside of the shank generally defines a vertical axis 50 and the angle u03b3 defined between the vertical axis 50 and the leading edge 52 of the blade 30.