To provide a drill capable of improving discharge performance of swarf while suppressing reduction of rigidity of a tip end of a cutting part.
On a tip end surface of a cutting part 12 of the drill 10, plural thinning surfaces 30c, 30d inclining toward a rear side of a drill rotation direction are continuously provided along the drill rotation direction. Among plural thinning surfaces 30c, 30d, the thinning surface 30c positioned at a position that is a foremost position of the drill rotation direction has an inclination angle θ1 of the inclined shape set larger than an inclination angle θ2 of the inclined shape of the thinning surface 30d positioned at a position that is a rear side of the drill rotation direction than the thinning surface 30c is positioned.
FUKUSHIMA HIROYUKI
MATSUMOTO SHINGO
Toshiyuki Miyadera
Shuji Ouchi
Yasuharu Nakasone
Shiro Sakai
Akira Yamano