A milling tool includes a rotatable tool body, a cutting insert, and first and second coolant outlets. The rotatable tool body is configured to rotate around an axis. The rotatable tool body includes a circumferential outer surface with a pocket defined therein. The pocket includes a seating surface. The cutting insert is disposed within the pocket. The cutting insert includes a seating face and a rake face opposed to the seating face. The seating face is disposed against the seating surface. The first coolant outlet is disposed in or attached to the rotatable tool body disposed on an opposite side of the rake face as the seating face. The second coolant outlet is disposed in or attached to the rotatable tool body disposed on an opposite side of the seating face as the rake face. The second coolant outlet is disposed outside of and adjacent to the seating face.

A rotary cutting tool includes: a blade portion; a shank portion having a diameter larger than a diameter of the blade portion; and a tapered connecting portion connecting the blade portion and the shank portion. The shank portion includes a plurality of coolant-guide recessed grooves provided in its outer circumferential surface. Each of the coolant-guide recessed grooves has a groove depth and a groove width that is larger than the groove depth. Each of the coolant-guide recessed grooves has a groove bottom that is shaped such that the groove depth is reduced as the each of the coolant-guide recessed grooves extends from its start end toward a groove-depth regional-change position in which a tendency of change of the groove depth is changed.

In a rotating tool with a coolant hole, a coolant hole extending to a front side in the direction of an axis opening to a tip flank face of a drill main body that is rotated around the axis. In a cross section orthogonal to the axis, the coolant hole is provided with a first concavely curved portion located on an inner peripheral side of the drill main body and formed in a concavely curved shape recessed to the inner peripheral side, a second concavely curved portion located on an outer peripheral side of the drill main body and formed in a concavely curved shape recessed to the outer peripheral side with a larger curvature radius than the first concavely curved portion, two third concavely curved portions having a center of a curvature radius located inside the coolant hole with a smaller curvature radius than the second concavely curved portion.

A cutting tool body includes a first member and a second member, both having a substantially cylindrical shape, and arranged such that a tool body central axis coincides with a central axis of each of the first and the second members. The first member has a tool characteristic of a first magnitude and the second member has the tool characteristic of a second magnitude, different from the first magnitude. The cutting tool body includes a transition member arranged between the first and second members and connected at a first end to the first member and at a second end to the second member. The tool characteristic in the transition member is of the first magnitude at the first end and of the second magnitude at the second end. The transition member has a transition region between the first and the second ends in which the tool characteristic transforms from the first magnitude to the second magnitude.

A cutting tool body includes a first member and a second member, both having a substantially cylindrical shape, and arranged such that a tool body central axis coincides with a central axis of each of the first and the second members. The first member has a tool characteristic of a first magnitude and the second member has the tool characteristic of a second magnitude, different from the first magnitude. The cutting tool body includes a transition member arranged between the first and second members and connected at a first end to the first member and at a second end to the second member. The tool characteristic in the transition member is of the first magnitude at the first end and of the second magnitude at the second end. The transition member has a transition region between the first and the second ends in which the tool characteristic transforms from the first magnitude to the second magnitude.

A rotary tool includes a coolant hole opening in a flank face. The coolant hole includes, in a cross section orthogonal to a rotational axis of the rotary tool, a first portion protruding toward a front in a rotation direction of the rotational axis and toward an outer peripheral side and having a convex curved shape, a second portion protruding toward the front in the rotation direction and toward a central side having a convex curved shape, and a third portion protruding toward a rear in the rotation direction and toward the central side and having a convex curved shape.

A rotary cutting tool includes: a blade portion; a shank portion having a diameter larger than a diameter of the blade portion; and a tapered connecting portion connecting the blade portion and the shank portion. The shank portion includes a plurality of coolant-guide recessed grooves provided in its outer circumferential surface. Each of the coolant-guide recessed grooves has a groove depth and a groove width that is larger than the groove depth. Each of the coolant-guide recessed grooves has a groove bottom that is shaped such that the groove depth is reduced as the each of the coolant-guide recessed grooves extends from its start end toward a groove-depth regional-change position in which a tendency of change of the groove depth is changed.

In a rotating tool with a coolant hole, a coolant hole extending to a front side in the direction of an axis opening to a tip flank face of a drill main body that is rotated around the axis. In a cross section orthogonal to the axis, the coolant hole is provided with a first concavely curved portion located on an inner peripheral side of the drill main body and formed in a concavely curved shape recessed to the inner peripheral side, a second concavely curved portion located on an outer peripheral side of the drill main body and formed in a concavely curved shape recessed to the outer peripheral side with a larger curvature radius than the first concavely curved portion, two third concavely curved portions having a center of a curvature radius located inside the coolant hole with a smaller curvature radius than the second concavely curved portion.

An embodiment milling cutter includes a cutter body rotatable about a rotation axis, wherein the cutter body includes a coupling region disposed in an outer region of the cutter body based on a radial direction and a flow path configured to communicate with the outside and define a space in which a cooling fluid flows, and wherein at least a part of a region of the flow path is disposed to be directed toward the coupling region. The embodiment milling cutter further includes an insert member coupled to the coupling region of the cutter body.

A tool holder (e.g., shrink fit adapter) with fluid directing passages includes a shank and a fluid/coolant directing structure including one or more nozzles fluidically connected to feeder channels of the shank. The one or more nozzles each include an inner wall and an outer wall configured/shaped to direct fluid/coolant flow both radially inwardly and longitudinally distally and/or to variably modulate fluid/coolant flow around a nozzle outlet of or provided by the nozzle(s) in relation to a longitudinal central axis of the shank. The fluid/coolant directing structure incorporates one of more of: a ring of peripherally located nozzles having geometries/orientations configured to focus and direct thin sheets of fluid/coolant both radially inwardly and distally longitudinally; manifolds for directly feeding nozzle inlets of distally located nozzles; and a nozzle provided by approximately sinusoidally varying surfaces circumferentially disposed about a tool receiving recess of the tool holder for correspondingly variably modulating fluid/coolant flow direction through and exiting from the nozzle.