Patent ID: 6406226
Filing Date: 2002-06-18
Classification: B23B,Y10S,Y10T

Abstract:
A throwaway tip for drilling a hole, comprising:an inner cutting edge provided at a front end of a drilling direction of the tip for cutting a center area of the hole; an outer cutting edge provided at the front end of the tip for cutting a circumference area of the hole; a first rake face provided on one side of the tip; a first bearing face provided on the other side of the tip in a back-to-back relation with the first rake face; a first front flank provided on the front end of the tip as intersecting the first rake face and the first bearing face; the inner cutting edge being defined as a ridge by an intersection between the first rake face and the first front flank and extending as crossing the drilling direction; a second rake face provided on the other side of the tip; a second bearing face provided on the one side of the tip in a back-to-back relation with the second rake face; and a second front flank provided on the front end as intersecting the second rake face and the second bearing face; the outer cutting edge being defined as a ridge by an intersection between the second rake face and the second front flank and extending as crossing the drilling direction; the first rake face being located at a lower level than the second bearing face on one side of the tip, and connected to the second bearing face by a first curved surface for guiding chips generated by cutting with the inner cutting edge.