Title:
DRILL
Document Type and Number:
Japanese Patent JP2020023051
Kind Code:
A
Abstract:
To provide a drill which can suppress generation of a long cut scrap.SOLUTION: A drill rotatable around a rotation axis 1 comprises a circular arc-shaped cutting edge 4, and a thinning cutting edge 2. The cutting edge 4 is located on a tip side when viewed from a direction along the rotation axis 1. The thinning cutting edge 2 is positioned on the rotation axis 1 side when viewed from the cutting edge 4 and is continued to the cutting edge 4. A ratio of a length L of the thinning cutting edge 2 to a diameter D of the drill, when viewed from the direction along the rotation axis 1, is not less than 6% and not more than 14%. A ratio of a curvature radius R of the cutting edge 4 to the diameter D of the drill, when viewed from the direction along the rotation axis 1, is not less than 25% and not more than 45%.SELECTED DRAWING: Figure 2
Inventors:
KAMISHIRO MASAAKI
YONEZAKI SHUSUKE
YONEZAKI SHUSUKE
Application Number:
JP2019208821A
Publication Date:
February 13, 2020
Filing Date:
November 19, 2019
Export Citation:
Assignee:
SUMITOMO ELECTRIC HARDMETAL CORP
International Classes:
B23B51/00; B23B51/06
Attorney, Agent or Firm:
Fukami patent office