| 摘要 |
An object of the invention is to provide a core cutter that allows a wall thickness of a base to be set freely and a gallet to be formed easily. A core cutter A comprises a cylindrical base, a plurality of cutting portions provided at a tip end of the base, and discharge grooves configured to discharge chips cut by the cutting portions, and an attaching portion, wherein each of the cutting portions 2 is constructed of a block and has at least three cutting blades including a first cutting blade 2a, a second cutting blade 2b, and a third cutting blade 2c, the first cutting blade 2a being located radially inward relative to the second and third cutting blades 2b and 2c and the second cutting blade 2c is located between the first and third cutting blades 1a and 1c in a radial direction of the base, wherein the first, second, and third cutting blades are arranged such that their circumferential positions deviate rearward in this order in a rotational direction of the core cutter, wherein a wall 3b of a rear end of the discharge groove 3 provided to correspond to a cutting surface 2k of the third cutting blade is located at the same position or rearward in the rotational direction relative to the cutting surface 2k of the third cutting blade, and wherein a gallet 4 for discharging chips is provided adjacent each cutting portion to be located forward relative to each cutting portion in the rotational direction, the gallet being formed by one surface which is formed by cutting an outer peripheral surface of a tip end portion of the base in such a manner that an inner end of the gallet is located radially inward relative to an outer end of the first cutting portion and protrudes to a lower position than an outer end of the gallet. |
