DRILL BODY OF CUTTING EDGE REPLACING TYPE DRILL, AND CUTTING EDGE REPLACING TYPE DRILL

摘要

PROBLEM TO BE SOLVED: To facilitate manufacturing of a drill body, secure strength, increase chip discharge performance, and improve cooling efficiency by facilitating reaching of a coolant to near a cutting edge.SOLUTION: A chip discharge groove 8 is provided with: a tip side twisted part 8a; a base end side twisted part 8b that has a twist angle θ smaller than that θ of the tip side twisted part 8a, and an intermediate twisted part 8c that is arranged between the tip side twisted part 8a and the base end side twisted part 8b. A coolant hole 10 is provided with: a first coolant hole 11 that is opened in a recess formed in the base end surface 9 of a drill body 2 or the base end surface 9 and that linearly extends in a drill rotational direction toward a tip side in the direction of an axis O; and a second coolant hole 12 that is connected to the tip part of the first coolant hole 11 in the direction of the axis O, that linearly extends in a direction different from the extending direction of the first coolant 11 from the tip part toward the tip side of the drill body 2, and that is opened in the chip discharge groove 8 closer to the tip side than the tip position of the base end twisted part 8b.SELECTED DRAWING: Figure 3