Anti-skive drill bit
An anti-skive drill bit including a body having a proximal end, a distal end, a longitudinal axis extending between the proximal and distal ends, and a flute extending longitudinally along the body. The distal end includes a distally facing region and a first channel defining a first channel surface. The distally facing region includes a relief surface having a first most-distal point at one of an intersection of an outer diameter of the body and a leading edge of the first flute, and an intersection of the outer diameter of the body and the first channel surface. The distally facing region has a relief surface angle between the relief surface and an outer diameter surface of the body at the first most-distal point of less than 90 degrees. The channel has a proximal end intersecting the first flute, and a distal end intersecting the relief surface.
1 . A drill bit comprising:
a body extending along a longitudinal axis between a proximal end and a distal end and having an outer diameter surface and a first flute extending longitudinally along the body; and
a distally facing region at the distal end comprising:
a relief surface intersecting both the first flute and the outer diameter surface, wherein a relief surface angle is defined between the relief surface and the outer diameter surface of the body at a first most-distal point of less than 90 degrees,
a first channel surface of a first channel intersecting each of the relief surface, the outer diameter surface of the body, and the first flute, wherein the first channel surface includes a first channel side, a second channel side, and a first root connecting the first channel side and the second channel side, and
a first inner cutting edge defined by an intersection of the first channel surface with the relief surface.
2 . The drill bit of claim 1 , further comprising a second flute;
wherein the relief surface defines a valley in the distal end of the body, and wherein a first outer cutting edge is defined at an intersection of the relief surface and the first flute, and wherein a second outer cutting edge is defined at an intersection of the relief surface and the second flute;
wherein the relief surface defines a first most-distal point and a second most-distal point, wherein the relief surface angle at each of the first most-distal point and the second most-distal point is less than 90 degrees; and
the distally facing region further comprises a second channel substantially parallel to the first channel and having a second channel surface intersecting each of the relief surface, the outer diameter surface of the body, and the second flute.
3 . The drill bit of claim 2 , wherein the first most-distal point and the second most-distal point are arcuately spaced from a most radially outward point of the first outer cutting edge and the second outer cutting edge.
4 . The drill bit of claim 3 , wherein the relief surface is substantially V-shaped and includes first and second substantially planar portions substantially parallel to a relief surface axis with the relief surface axis intersecting and substantially normal to the longitudinal axis.
5 . The drill bit of claim 4 , wherein a first engagement line passes through the first most-distal point and extends across the relief surface and toward the longitudinal axis and a second engagement line passes through the second most-distal point and extends across the relief surface and toward the longitudinal axis.
6 . The drill bit of claim 2 , wherein the second channel surface includes a third channel side, a fourth channel side, and a second root connecting the third and fourth channel sides with the third and fourth channel sides corresponding respectively to the first channel side and the second channel side, and a second inner cutting edge corresponding to the first inner cutting edge and the second inner cutting edge being defined by an intersection of the second channel surface with the relief surface.
7 . The drill bit of claim 6 , wherein:
each of the first root and the second root includes:
a root axis that is substantially a straight line,
a first root plane passing through the root axis parallel to the longitudinal axis located a first distance from the longitudinal axis, and
a second root plane passing through the root axis normal to the first root plane at a root angle to the longitudinal axis;
for the first channel:
the first channel side is substantially planar and is coplanar with the root axis of the first root and is at a first channel angle to the second root plane of the first root, and
the second channel side is substantially planar and is coplanar with the root axis of the first root and is at a second channel angle to the second root plane of the first root; and
for the second channel:
the third channel side is substantially planar and is coplanar with the root axis of the second root and is at the first channel angle to the second root plane of the second root, and
the fourth channel side is substantially planar and is coplanar with the root axis of the second root and is at the second channel angle to the second root plane of the second root.
8 . The drill bit of claim 7 , wherein the first channel angle is less than 90 degrees, and the second channel angle is substantially equal to 90 degrees.
9 . The drill bit of claim 7 , wherein the first inner cutting edge is defined by the intersection of the second channel side with the relief surface and the second inner cutting edge is defined by the intersection of the fourth channel side with the relief surface.
10 . The drill bit of claim 6 , wherein the first channel side of the first channel surface is substantially planar and substantially parallel to the longitudinal axis and the third channel side is substantially planar and substantially parallel to the longitudinal axis.
11 . The drill bit of claim 2 , wherein the relief surface is arcuate between a bottom of the relief surface and each of the first most-distal point and the second most-distal point.
12 . The drill bit of claim 2 , wherein the relief surface angle is less than 70 degrees.
13 . The drill bit of claim 1 , wherein the first root defines a substantially straight first root axis;
wherein a first root plane passing through the first root axis is parallel to the longitudinal axis and is located a first distance from the longitudinal axis;
wherein a second root plane passing through the first root axis is normal to the first root plane and is at a root angle to the longitudinal axis;
wherein the first channel side is substantially planar and is substantially coplanar with the first root axis and is at a first channel angle to the second root plane; and
wherein the second channel side is substantially planar and is substantially coplanar with the first root axis and is at a second channel angle to the second root plane.
14 . The drill bit of claim 13 , wherein the root angle is less than 80 degrees.
15 . The drill bit of claim 13 , wherein the first channel angle is less than 90 degrees, and the second channel angle is substantially equal to 90 degrees.
16 . The drill bit of claim 13 , wherein the first inner cutting edge is defined by an intersection of the second channel side with the relief surface.
17 . The drill bit of claim 1 , wherein a first outer cutting edge is defined by an intersection of the relief surface and the first flute.
18 . The drill bit of claim 1 , wherein the relief surface angle is less than 70 degrees.
19 . The drill bit of claim 1 , wherein the first most-distal point is arcuately spaced from a most radially outward point of the first inner cutting edge.
20 . The drill bit of claim 1 , wherein the relief surface is substantially planar and an engagement line passes through the first most-distal point and extends across the relief surface and toward the longitudinal axis.