Abstract: A gun drill for forming a hole in a metal workpiece consisting of a generally cylindrical body having a shank portion and a tip portion. The body has a longitudinally extending groove formed in its outer surface which extends the full length of the tip portion, and the terminal end of the tip portion has a single cutting edge which extends radially through the axis of the tip portion adjacent the terminal end of the groove. The tip portion is formed intermediate its ends with a wall section located to one side of the groove and in substantial alignment with the cutting edge in a direction longitudinally of the body. A pair of fluid passages are formed in the body, one terminating at the wall section in an orifice directed toward the cutting edge, and the other terminating in an orifice located in the terminal end of the tip portion in a spaced relation with the cutting edge.