To provide a drill capable of drilling with higher degree of accuracy compared with a conventional drill.
In a peripheral surface 13 of a blade part which is the tip side part of a drill body 10 rotated around an axis CL, two main grooves 20, 30 are extended from a pair of tip flanks 12a, 12b formed on a tip surface 12 of the blade part toward a base end side. The drill includes: a first cutting edge 21 formed on a cross ridgeline between a wall surface 22 facing the forward side in the drill rotational direction K of one main groove in the two main grooves and the tip flank 12a, and extended to the peripheral end of the drill body; and a second cutting edge 31 formed in an inner circumference side area of a cross ridgeline between a wall surface 32 facing the forward side in the drill rotational direction K of the other main groove having a shorter groove length compared with the one main groove 20 and the tip flank 12b of the blade part except a non-cutting part 41 formed by a minor groove 40 notching a peripheral part of the cross ridgeline and the wall surface 32 connected to the peripheral part to a rear side in a drill rotational direction K.
COPYRIGHT: (C)2010,JPO&INPIT
MOCHIZUKI MANABU
NISHI TOSHIKAZU
| JPH0740117A | 1995-02-10 | |||
| JP2006150553A | 2006-06-15 | |||
| JPS6452610U | 1989-03-31 | |||
| JPS63267153A | 1988-11-04 | |||
| JPS6185307U | 1986-06-05 | |||
| JPH01153229A | 1989-06-15 | |||
| JPH0740117A | 1995-02-10 | |||
| JP2006150553A | 2006-06-15 | |||
| JPS6452610U | 1989-03-31 | |||
| JPS63267153A | 1988-11-04 | |||
| JPS6185307U | 1986-06-05 | |||
| JPH01153229A | 1989-06-15 |