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 cutting edge 21 formed on a cross ridgeline between a wall surface 22 facing to 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 10; a non-cutting part 31 formed on a cross ridgeline between a wall surface 32 facing to 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 and the tip flank 12b, and which recedes in the base end side from the cutting edge 21 and is not brought into contact with a cutting material; and lands 23, 33 formed on the peripheral surface 13 of the blade part connected to the peripheral edge of the one main groove and the other main groove so as to be capable of coming into slide-contact with the inner circumference wall surface of a machined hole.
COPYRIGHT: (C)2010,JPO&INPIT
MOCHIZUKI MANABU
NISHI TOSHIKAZU
| JPS63267153A | 1988-11-04 | |||
| JP2006150553A | 2006-06-15 | |||
| JPS63260710A | 1988-10-27 | |||
| JPS6452610U | 1989-03-31 |
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