23 Twist Drills, Screw Thread Taps and Screw Cutting Dies; Milling Cutters, Reamers, Broaches and Milling, Broaching, Gear Hobbing, Gear Cutting and Drilling Machine Tools, Gear Grinding Machines, Screw Thread Grinding Machines, and Gap Grinding Machines; Spline, Thread and Gear Hobs and Transmission Clutches All Being Parts of Machines