12-28 4 Flutes H3 Straight Flute Hand - Machine Screw Plug Tap

For general use in hand and production tapping. For hand tapping in relatively hard materials or in bottoming holes the use of taper, plug and bottoming taps, in the order given, is suggested. The taper tap is helpful in starting the thread square with the work piece. The plug tap is, however, the most widely used tap in both hand and production tapping.