POSITIONING APPARATUS

摘要

Apparatus for positioning a twist drill (40) in a cradle (30). The drill has one or more helical grooves extending along its length from a terminal end having a cutting formation. The apparatus includes a seat (22) for locating the cradle in predetermined position and a stop axially spaced from the seat against which said terminal end of a drill located in the cradle may abut in order to set the axial position of the drill in the cradle (30). It also includes rotation means capable of gripping a drill in the cradle and rotating it to a predetermined rotary position for setting the rotary position of the drill relative to the cradle. The rotation means includes a pair of opposed clamping jaws (71, 72) arranged to clampingly engage diametrically opposite sides of the drill. At least one of the jaw has an elongate drill engagement surface which has a width less than the width of said grooves and which extends longitudinally in a lateral direction relative to the axis of the drill so as to be capable of engaging both opposed side edges of a facing groove such that when the pair of jaws are closed to clamp opposite sides of the drill, said elongate engagement surface engages one side edge of t facing groove and causes the drill to rotate until both opposed side edges are engaged by said engagement surface.