Twist drills

Parts of a twist drill
Shank The end of the drill that is held by the machine is called the shank, this can be a straight shaft equal to the diameter of the drill or less then the diameter of the drill. Drills can also have Morse taper shanks, this is more common for drills over 1/2" because it provides additional strength, and because the average chuck can only hold up to a 1/2" shaft. Flutes The spiraled channels that help chips to escape from the hole being drilled are called flutes. They are manufactured with varying angles to achieve different rates of chip removal. The flutes also have lands that ride on the inside of the hole.