Title:
THREE-BLADED TWIST DRILL
Document Type and Number:
Japanese Patent JP2012056069
Kind Code:
A
Abstract:
To provide a three-bladed twist drill that reduces cutting resistance while suppressing reduction in rigidity and improves chip evacuation performance.
The three-bladed twist drill has thinning sections 7 formed at a tip thereof. When directly viewing the thinning sections from a side of the tip in a direction of an axis of the drill, the thinning sections are formed such that curved ridgelines 12 are each formed between a front edge relief surface 8 and a second surface 9, a thinning opening angle β in the thinning sections is set to be 90° or more and ≤100° and a ratio A/B of a front-edge-relief-surface forming region angle A to a second-surface forming region angle B is set to be ≥1.5.
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Inventors:
SATO YOSHIJI
KAMISHIRO MASAAKI
KAMISHIRO MASAAKI
Application Number:
JP2010204388A
Publication Date:
March 22, 2012
Filing Date:
September 13, 2010
Export Citation:
Assignee:
SUMITOMO ELEC HARDMETAL CORP
International Classes:
B23B51/00
Domestic Patent References:
| JP2007502717A | 2007-02-15 | |||
| JPH05301108A | 1993-11-16 |
Foreign References:
| WO2003035310A1 | 2003-05-01 | |||
| WO2010038279A1 | 2010-04-08 |
Attorney, Agent or Firm:
Bunji Kamada
Higashio Masahiro
Takayoshi Tagawa
Higashio Masahiro
Takayoshi Tagawa