A drilling tool includes a tool body having a center axis defining a longitudinal direction of the drilling tool. The tool body has an axially forward end and an axially rearward end, the distance in the longitudinal direction between the forward end and the rearward end defining a length of the drilling tool. At least two indexable cutting inserts are arranged at the axially forward end, a first indexable cutting insert being arranged at a radially inner position and a second indexable cutting insert being arranged at a radially outer position. The tool body includes a first flute portion extending axially rearward from the first indexable cutting insert and a second flute portion extending axially rearward from the second indexable cutting insert. The first flute portion transitions into the second flute portion at an axially forward transition area of the tool body, thereby forming only one flute of the tool.

An indexable drill insert includes a drill body having a central longitudinal rotational axis (CL), the drill body comprising a shank portion and a fluted cutting portion, the fluted cutting portion having a front clearance face and a plurality of flutes, the fluted cutting portion includes a central insert pocket capable of receiving a central cutting insert and a peripheral insert pocket capable of receiving a peripheral cutting insert. For the central cutting insert, a central, longitudinal axis of a projection of the flute coolant exit aperture can intersect a vertical plane (PA1) having an area (A1) or a horizontal plane (PB1) having an area (A2). For the peripheral cutting insert, the central, longitudinal axis of the projection can intersect a vertical plane (PA2) having an area (A3) or a horizontal plane (PB2) having an area (A4).

A straight line along the second line segment and a straight line along the fourth line segment form an acute angle. The straight line along the second line segment and the straight line along the third line segment form an obtuse angle. The straight line along the first line segment and the straight line along the fourth line segment form an obtuse angle. Each of the third curved portion and the fourth curved portion is larger in radius of curvature than the first curved portion and larger in radius of curvature than the second curved portion. In a direction perpendicular to the bottom surface, a distance between the top surface and the bottom surface is equal to a distance between the cutting edge and the bottom surface, or is shorter than the distance between the cutting edge and the bottom surface.

Drilling tool systems including a drilling body and a drilling inserts are disclosed. The drilling inserts include four indexable cutting edges. The four cutting edges may each comprise a plurality of cutting edge segments and a wiper edge. The plurality of cutting edge segments and the wiper edge are provided at distinct angles to provide effective chip breaking and a stronger cutting edge at the drilling insert corners. Furthermore, the side surfaces of the drilling inserts allow the drilling insert to be more stably supported in a pocket of the drilling body. The drilling inserts may be used in a peripheral pocket of a drilling body.

An indexable drilling tool, includes a cutter body, an outer blade and an inner blade. The inner blade is surrounded by a first upper surface, a first lower surface and a first side surface. The first upper surface intersects with the first side surface to form multiple identical inner cutting edges. When drilling, a cutting area of the inner cutting edge as a main cutting edge is located between a central inner point and a central outer point on the inner cutting edge. In a feed direction, an inner convex cutting portion with a maximum cutting depth is arranged between the central inner point and the central outer point. Distances between the central inner point and the inner convex cutting portion and between the central outer point and the inner convex cutting portion in an axial direction are H1 and H2 respectively, which meets the following requirement: 0.9H2≤H1≤1.1H2.

A drilling tool includes a tool body having a center axis defining a longitudinal direction of the drilling tool. The tool body has an axially forward end and an axially rearward end, the distance in the longitudinal direction between the forward end and the rearward end defining a length of the drilling tool. At least two indexable cutting inserts are arranged at the axially forward end, a first indexable cutting insert being arranged at a radially inner position and a second indexable cutting insert being arranged at a radially outer position. The tool body includes a first flute portion extending axially rearward from the first indexable cutting insert and a second flute portion extending axially rearward from the second indexable cutting insert. The first flute portion transitions into the second flute portion at an axially forward transition area of the tool body, thereby forming only one flute of the tool.

Drilling tool systems including a drilling body and a drilling inserts are disclosed. The drilling inserts include four indexable cutting edges. The four cutting edges may each comprise a plurality of cutting edge segments and a wiper edge. The plurality of cutting edge segments and the wiper edge are provided at distinct angles to provide effective chip breaking and a stronger cutting edge at the drilling insert corners. Furthermore, the side surfaces of the drilling inserts allow the drilling insert to be more stably supported in a pocket of the drilling body. The drilling inserts may be used in a peripheral pocket of a drilling body.

Drilling tool systems including a drilling body and a drilling inserts are disclosed. The drilling inserts include four indexable cutting edges. The four cutting edges may each comprise a plurality of cutting edge segments. The plurality of cutting edge segments are provided at distinct angles with respect to a reference plane of the drilling insert to provide effective chip breaking and a stronger cutting edge at the drilling insert corners. Furthermore, the side surfaces of the drilling inserts allow the drilling insert to be more stably supported in a pocket of the drilling body. The drilling inserts may be used in a central pocket of a drilling body.

An insert according to an embodiment includes an upper surface including a corner part, a lower surface, a side surface, and a cutting edge. The cutting edge includes a first cutting edge located at the corner part, a second cutting edge adjacent to the first cutting edge, a third cutting edge adjacent to the second cutting edge, and a fourth cutting edge adjacent to the third cutting edge. Each of the third cutting edge and the fourth cutting edge has a concave curvilinear shape extending downward in a side view. A radius of curvature of the fourth cutting edge is smaller than a radius of curvature of the third cutting edge.

Drilling tool systems including a drilling body and a drilling inserts are disclosed. The drilling inserts include four indexable cutting edges. The four cutting edges may each comprise a plurality of cutting edge segments. The plurality of cutting edge segments are provided at distinct angles with respect to a reference plane of the drilling insert to provide effective chip breaking and a stronger cutting edge at the drilling insert corners. Furthermore, the side surfaces of the drilling inserts allow the drilling insert to be more stably supported in a pocket of the drilling body. The drilling inserts may be used in a central pocket of a drilling body.