| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a drill excellent in discharging performance of chip, and to provide a method of manufacturing a machined product. <P>SOLUTION: The drill 1 includes a substantially cylindrical cutting portion 3 including a first region 10 located at a front end portion, and a second region 20 which has a step 25 whose diameter increases as going from the first region 10 to a rear end and which is continuous with the first region 10 in an end 20a on a side of the step 25. The second region 20 has a plurality of second rake surfaces positioned between a plurality of second cutting blades 21 and a plurality of second grooves 23, the plurality of second rake surfaces each having a second center surface decreasing in length W2 in a direction parallel to an axis S of rotation toward an outer peripheral portion side, and a second outward surface positioned more on the outer peripheral side than the second center surface and increasing in length W2 toward the outer peripheral portion side. There is provided a method of manufacturing a machined product using the drill 1. <P>COPYRIGHT: (C)2013,JPO&INPIT |
