Abstract: A method of machining a differential housing defining a cavity having opposed concave interior surfaces from a workpiece having first and second transverse bores defined therein. A tool having a retractable cutting insert is mounted on a spindle of a machining center, the cutting insert being pivotably mounted within the tool to rotate about a pivot axis and having distal and proximal cutting edges at opposite ends thereof. The tool is inserted into the first bore defined in the workpiece while the cutting insert is retained in a retracted position within the tool. A force is applied to the cutting insert so as to overcome a bias urging the cutting insert into the retracted position, the force being sufficient to urge the distal and proximal cutting edges into contact with corresponding interior portions of the work piece.

Abstract: A polycrystalline diamond (PCD) tipped tool for producing holes in non-ferrous and non-metallic composite materials without delamination. The tool comprises an elongated body portion having a distal cutting region and a proximal shank region and first and second cutting regions including first and second planar surfaces, respectively. The planar surfaces diverge in a direction from the distal cutting region toward the proximal shank region to define a cutting angle that is preferably about 120.degree..A first axial flute separates a forward edge of the first cutting region from a trailing edge of the second cutting region and a second axial flute radially opposed to the first axial flute separates a forward edge of the second cutting region from a trailing edge of the first cutting region. Each of the first and second cutting regions further includes a planar surface forming with a forward edge thereof respective first and second clearance angles of between 10.degree. to 20.degree.