Patent ID: 7901163
Filing Date: 2011-03-08
Classification: B23B,Y10T

Abstract:
1. A gun drill including at least one cutter head having a coolant discharge port communicating with a coolant supplying path at the distal end face at the distal end of a hollow shank portion having a cutting chip discharge groove, whose section along the lengthwise direction is V-shaped, on the outer surface and having the interior thereof made into a coolant supplying path, wherein: a blade portion of the at least one cutter head is made of a cemented carbide alloy, and at the same time, at least a part of the slide-contacting portion to the inner circumference of the at least one cutter head excluding the blade portion is composed of a dissimilar material having higher hardness than the cemented carbide alloy; and the slide-contacting portion comprises a swell portion formed along an outer circumferential portion of the cutter head, the swell portion being made of the same material as the blade portion.