Patent ID: 8753049
Filing Date: 2014-06-17
Classification: B23B,Y10T

Abstract:
1. A cutting tool comprising: a body that rotates about an axis center; a hole portion that is open in a tip end surface of the body; a wall portion that is formed of the hole portion and an outer circumferential surface of the body; a notch portion that is notched from the tip end surface of the wall portion and is communicated with the hole portion; and a blade portion that is formed or held at a portion where the notch portion intersects with the tip end surface of the wall portion, wherein: the blade portion includes a bottom blade formed at a tip end in a direction of axis center, and an inner side surface that passes through an inner end portion of the bottom blade and intersects with a rake surface through a ridge line; the inner side surface is inclined so that a distance between the inner side surface and the axis center is increased towards a direction opposite to a rotational direction of the body; the hole portion is centered by an axis line which is deviated from the axis center of the body; the blade portion is formed or held at the thickest portion of the wall portion; a center angle relative to the wall portion is set in a range from 180° to 270°; and when the notch portion is indented starting from the thickest portion of the wall portion, the end of the notch portion is formed in a direction from the outer circumferential surface of the body to a position where an imaginary line passing through the axis center and the axis line intersects with an inner circumferential surface of the hole portion.