Boring head assembly

An adjustable dual cutting insert boring tool for forming a hole in a metal workpiece, comprising:

• a tool body having a shank adapted to be coupled to a rotary drive means, the tool body having a longitudinal rotating axis;
• a first cutting tool insert and a second cutting tool insert;
• means for supporting said first cutting tool insert and said second cutting tool insert at equal radial distances from said rotating axis for rotation in an annular path of motion defining the diameter of a hole being cut in a workpiece:
• an elongated adjusting screw, and means for mounting the adjusting screw on the body for rotation about an adjusting screw axis disposed at right angles to and intersecting said tool body rotating axis, the adjusting screw having a right-hand threaded section and a left-hand threaded section, both of said threaded sections being disposed along the adjusting screw axis;
• a first cartridge tool carrier having a bore with an internal left-hand thread threadably receiving the left-hand threaded section on the adjusting screw;
• a second cartridge tool carrier having a bore with an internal right-hand thread threadably receiving the right-hand threaded section on the adjusting screw such that the first and the second cartridge tool carriers are moved in an outward radial direction away from said rotating axis as the adjusting screw is rotated in a first direction and moved in an inward radial direction as the adjusting screw is rotated in the opposite direction;
• first means mounted on the first cartridge tool carrier and supporting the first cutting tool insert such that the first cutting tool insert moves in a radial direction with the first cartridge tool carrier;
• second means mounted on the second cartridge tool carrier and supporting the second cutting tool insert such that the second cutting tool insert moves in a radial direction with the second cartridge tool carrier;
• the tool body having an elongated cavity having end walls enclosing said rotating axis, and bore means on said end walls for supporting the ends of the adjusting screw such that the right-hand and left-hand threaded sections are disposed between said end walls;
• the cavity having a pair of opposed parallel sidewalls, and at least one of the cartridge tool carriers having an inner guide disposed between the sidewalls of the elongated cavity, moveable along a path of motion parallel to the adjusting screw axis, and including a side plate having a complementary lip mounted on the body to engage said at least one of the cartridge tool carriers;
• first fastener means for fastening the side plate to the body, and second fastener means for clamping said at least one of the cartridge tool carriers in an adjusted position with respect to the body;
• whereby the two cutting tool inserts move in a common annular cutting path as the tool body is rotated in a power motion.