CORE CUTTER

摘要

An object of the present invention is to provide a core cutter capable of smoothly discharging chips and delivering high drilling performance. A core cutter C includes a tubular body portion 1 and a plurality of cutting blades 2 arranged at a tip end of the body portion 1 at predetermined intervals in a circumferential direction. At least one of the plurality of cutting blades 2 serves as an inner cutting blade 2A, and the remaining cutting blades 2 serve as outer cutting blades 2B. The thickness of the body portion 1 is made thin while maintaining distortion resistance of the body portion 1. Through grooves 3 configured to penetrate a tip end of the body portion 1 in a thickness direction are formed so as to open toward a tip end side of the core cutter. The cutting blades 2 are attached to the through grooves 3, each of the cutting blades 2 having the same circumferential-direction size as the through groove 3 and being constituted by a block separately from the body portion 1. Each of gallets 4 configured to discharge the chips is formed on a rotational-direction front side of the cutting blade 2, each of the gallets 4 being formed by an outer peripheral surface formed so as to approach to an inner peripheral surface as the outer peripheral surface extends toward the tip end side of the body portion. The cutting blades 2 are respectively welded to the through grooves 3 such that a radially inner end of an axial-direction tip end portion of each of the cutting blades 2 coincides with or substantially coincides with a peripheral surface of an axial-direction tip end portion of the gallet 4.