Abstract: An orbital drill includes a drilling portion, a shank portion, and a neck portion between the drilling portion and the shank portion. The drilling portion includes one or more right-handed spiral flutes with cutting edges having a positive axial rake angle for positive cutting action while orbiting into a material. The right-handed spiral flutes have a positive radial and axial rake angle. The drilling portion also includes one or more left-handed spiral flutes located rearward of the one or more right-handed spiral flutes with cutting edges having a positive axial and radial rake angle for positive cutting action while orbiting back out of the material and removing any material left in the hole, thereby eliminating a separate reaming operation. A method of machining a workpiece using the orbital drill is also disclosed.

Abstract: An orbital drill includes a drilling portion, a shank portion, and a neck portion between the drilling portion and the shank portion. The drilling portion includes one or more right-handed spiral flutes with cutting edges having a positive axial rake angle for positive cutting action while orbiting into a material. The right-handed spiral flutes have a positive radial and axial rake angle. The drilling portion also includes one or more left-handed spiral flutes located rearward of the one or more right-handed spiral flutes with cutting edges having a positive axial and radial rake angle for positive cutting action while orbiting back out of the material and removing any material left in the hole, thereby eliminating a separate reaming operation. A method of machining a workpiece using the orbital drill is also disclosed.

Abstract: In one aspect, rotationally balanced asymmetric end mills are described herein. An end mill described herein comprises a shank portion extending along a longitudinal axis of the end mill, and a cutting portion extending from the shank portion. The cutting portion comprises a plurality of unequally indexed blades separated by flutes along an axial length of cut, the blades extending onto a cutting end surface of the end mill, wherein at least one of the flutes is of unequal length and the asymmetric end mill has an imbalance of 2.0 gmm or less.