Orbital drill with left-handed and right-handed flutes

An orbital drill, comprising:

• a drilling portion;
• and
• a shank portion;
• and
• a neck portion between the drilling portion and the shank portion,
• wherein the drilling portion includes a first flute having a right-handed helix configuration with a first cutting edge having a positive axial rake angle for positive cutting action while orbiting into a material to form a hole in the material using a first orbital drilling operation, and a second flute located rearward of the first flute and having a left-handed helix configuration with a second cutting edge having a positive axial rake angle for positive cutting action while orbiting back out of the material using a second orbital drilling operation, thereby removing any residual material in the hole due to deflection of the cutting tool when orbiting into the material using the first orbital drilling operation, thereby eliminating a separate reaming operation;
• and
• wherein the first cutting edge overlaps the second cutting edge in the axial direction.

A method of machining a workpiece using an orbital drill, the orbital drill comprising a drilling portion and a shank portion, wherein the drilling portion includes a first flute having a right-handed helix configuration with a first cutting edge having a positive axial rake angle, and a second flute located rearward of the first flute and having a left-handed helix configuration with a second cutting edge having a positive axial rake angle and overlapping the first cutting edge in the axial direction, the method comprising:

• positioning the orbital drill with respect to a workpiece to begin a machining cycle;
• and forming a hole in the workpiece with the cutting edge of the first flute with the right-handed spiral configuration using a first orbital drilling operation;
• and
• moving the orbital drill out from the hole in the workpiece using a second orbital drilling operation,
• wherein residual material due to deflection of the orbital drill when forming the hole in the workpiece using the first orbital drilling operation is removed from the hole using the cutting edge of the left-handed spiral flutes when moving the orbital drill out from the workpiece using the second orbital drilling operation.