a conterbore

1 definition found

a conterbore - Collaborative International Dictionary of English v.0.48 :

  Countersink \Coun"ter*sink`\, n.
     1. An enlargement of the upper part of a hole, forming a
        cavity or depression for receiving the head of a screw or
        bolt.
        [1913 Webster]
  
     Note: In the United States a flaring cavity formed by
           chamfering the edges of a round hole is called a
           countersink, while a cylindrical flat-bottomed
           enlargement of the mouth of the hole is usually called
           a conterbore.
           [1913 Webster]
  
     2. A drill or cutting tool for countersinking holes.
        [1913 Webster]