To provide a rotary cutting tool capable of ensuring insert fitting rigidity and executing lathe machining with high accuracy by matching the center of a cutting blade forming a circumferential shape of a cut insert with the axis of a tool body, and reliably supporting the cut insert immediately below the cutting blade under the cutting resistance.
A disk-shaped cut insert 13 is fitted to the insert fitting seat 12 of the neck part 11B of a tool body 11 coaxially with the axis O of a shank part 11A. The insert fitting seat 12 has a bottom face 12A facing a seating surface 15 of the cut insert 13, and a wall surface 12B abutted on the circumferential surface 16 of the cut insert 13. Recessed grooves 20, which are recessed from the bottom face 12A and turn around the axis O, and open at a plurality of sections in the circumferential direction on the outer circumference face 11C of the neck part 11B, are formed on the bottom face 12A with a spacing from the wall face 12B. A supporting face 21 abutted on an outer circumferential side edge of the seating surface 15 is formed between the recessed grooves 20 and the wall surface 12B.
NARITA TORU
TAKEDA KOHEI
Tadashi Takahashi
Yasuhiko Murayama
Noriko Yanai