Counterbore

3 definitions found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Counterbore \Coun"ter*bore`\ (-b?r`), n.
     1. A flat-bottomed cylindrical enlargement of the mouth of a
        hole, usually of slight depth, as for receiving a
        cylindrical screw head.
        [1913 Webster]
  


     2. A kind of pin drill with the cutting edge or edges normal
        to the axis; -- used for enlarging a hole, or for forming
        a flat-bottomed recess at its mouth.
        [1913 Webster]

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Counterbore \Coun`ter*bore"\ (koun`t?r-b?r"), v. t.
     To form a counterbore in, by boring, turning, or drilling; to
     enlarge, as a hole, by means of a counterbore.
     [1913 Webster]

From WordNet (r) 2.0 [wn]:

  counterbore
       n : a bit for enlarging the upper part of a hole [syn: {countersink},
            {countersink bit}]