| 摘要 |
An insert (24) and tool holder (10) for threading operations comprises an insert having converging end wall regions (20,22) and parallel sides and parallel top and bottom walls perpendicular to said sides. The insert is invertable about the axis perpendicular to its sides and is adapted for mounting in the pocket (12) of a tool holder with one end region exposed. A recess (50) is formed in at least one of the top and bottom walls along the outer edges with an outer region forming cutting edges at its juncture with the end wall region. The recess also has an inner region in the form of an abrupt rise leading from the lowermost part of the outer region upwardly to the plane of the top or bottom wall. The cutting edges are angled so that when the insert is placed in a negative rake holder the cutting edges can be presented at zero or positive rake to the workpiece. <IMAGE> |
