Vermont American 21739 Tap and Die Set, Red, 58-Piece Tap Taps: 8 to 10 threads chamfered for easy starting in tough materials Plug Taps: 3 to 5 threads chamfered for general use when tapping to bottom of hole is not critical (this is the most widely used type of tap) Bottoming Taps: 1-1/2 threads chamfered for use where thread must go to bottom of hole Heat treated and tempered carbon tool steel. Smooth, accurate threading 58 piece set that contains: tap and hexagon die sizes