Combination machining lathe

A combination machining lathe comprising:

• a workpiece holding device configured to hold a workpiece in a manner that permits the workpiece to rotate around an axis parallel to a direction of a horizontal Z axis;
• a tool post having a tool mount portion configured to hold a first tool, the first tool comprising a first holder and a first bit, the first holder having a longitudinal axis extending lengthwise, and being held by the tool mount portion of the tool post, the first bit being provided at an end, lengthwise, of the first holder, where a longitudinal axis of the first bit is angled with respect to the longitudinal axis of the first holder, at least one of the tool post and the workpiece holding device being configured to be movable to allow relative movement of the first tool held by the tool mount portion of the tool post and the workpiece held by the workpiece holding device in three directions of an X axis, a Y axis and the Z axis, the X axis being perpendicular to the Z axis, the Y axis being perpendicular to the Z axis and to the X axis, the tool post being configured to perform an operation of indexing the first tool held by the tool mount portion of the tool post to a position in which the longitudinal axis of the holder is parallel to the X axis direction;
• a controller configured to index the first tool to a position where the axis of the first holder held by the tool mount portion of the tool post is parallel to the X axis, and the axis of the first bit at the end of the first holder is angled with respect to the X axis in an X-Y plane, and to control the relative movement of the first tool and the workpiece so that the first tool is fed in the axis direction of the first bit into a workpiece that is being rotated, with the axis of the first holder maintained parallel to the X-axis;
• and
• a tool exchanger for use in replacing the first tool held by the tool post with a second tool, the second tool comprising a second holder having a longitudinal axis and a second bit having a longitudinal axis,
• wherein a longitudinal axis of the tool post is co-axial with the longitudinal axis of the first holder;
• wherein the tool exchanger is configured to replace the first tool with the second tool such that an angle between the longitudinal axis of the second bit of the second tool and the longitudinal axis of the second holder of the second tool is different from an angle between the longitudinal axis of the first bit of the first tool and the longitudinal axis of the first holder of the first tool;
• wherein the controller is configured to index the tool post to a position where the longitudinal axis of the second holder of the second tool is parallel to the X axis, and, after replacing the first tool with the second tool, the controller is configured to change a direction of relative movement of the second tool and the workpiece from along the longitudinal axis of the first bit of the first tool to along the longitudinal axis of the second bit of the second tool, and
• wherein the longitudinal axis of the second bit is angled in the X-Y plane relative to the X axis and a horizontal plane.