A milling cutter includes a cutting section extending from a shank along an axis. The shank includes a free end as a first end of the milling cutter. The cutting section includes a free end as a second end of the milling cutter. The cutting section includes at least one right-hand cutting unit, at least one left-hand cutting unit and at least two grooves about the axis. Each of the grooves is made between the right-hand cutting unit and the left-hand cutting unit. The right-hand cutting unit includes several right-hand blades extending at a first helical angle relative to the axis. The left-hand cutting unit includes several left-hand blades extending at a second helical angle relative to the axis.

A rotating tool includes a tool body which rotates around an axial line, four or more chip discharge grooves which are formed on an outer periphery of the tool body with gaps therebetween in a circumferential direction, and a plurality of cutting inserts which are arranged in multiple stages along the chip discharge grooves. In a cross-sectional view perpendicular to the axial line, when a center angle formed between a pair of virtual straight lines which connects each of the cutting edges of the cutting inserts disposed in a pair of chip discharge grooves adjacent to each other in the circumferential direction and the axial line to each other is defined as an angle, a plurality of angles formed around the axial line include one maximum angle (max), one minimum angle (min), and two or more angles other than the angle (max) and the angle (min).

A rotatable cutting tool includes an elongate body having a longitudinal axis, a proximal end and a distal end and at least one helical flute extending over a length of the elongate body, the helical flute having a first end and a second end. The flute includes a cutting-edge with a first radius from a longitudinal center of the cutting tool, a trailing edge with a second radius from a longitudinal center of the cutting tool, wherein the second radius is smaller than the first radius, a flute surface between the cutting-edge and the trailing edge, the flute surface including a maximum radius at the cutting-edge and a plurality of foam chip shedding exclusions spaced along the cutting-edge of the helical flute, each of the foam chip shedding exclusions providing a gap in the cutting-edge where the radius within the gap is smaller than the first radius.

A bur with features that minimize the application of substantially identical forces to the tissue against which the bur is applied. One of these features is the arrangement of the flutes so that one pair of flutes projects outwardly from the tip at an acute angle that is greater than the angle at which the other flutes project outwardly from tip. Consequently at the equator of the bur head, the location along the bur head where the bur head has a maximum diameter, the flutes define a perimeter that is non-circular in shape.

A rotatable cutting tool is disclosed and includes an elongate body having a longitudinal axis, a proximal end and a distal end. The cutting tool further includes at least one helical flute extending over a cutting length of the elongate body, the helical flute having a first end and a second end. The helical flute includes a leading cutting wall having an edge, a trailing cutting wall having an edge, and a flute surface between the leading cutting wall and the trailing cutting wall, the flute surface including a curved surface portion including a constant radius from the longitudinal axis of the elongate body. The cutting tool further includes a plurality of reliefs evenly spaced along the leading and trailing walls of the helical flute, each of the reliefs forming a semi-circular cutout on the flute surface, and wherein the reliefs in the trailing cutting wall are longitudinally offset from the reliefs in the leading cutting wall.

A tool for machining a stacked material workpiece includes a tool body having one or more helical flutes extending to a forward end of the tool body. Each helical flute has a width defined by a first cutting edge and a second edge, a surface of the flute adjacent the first cutting edge facing the forward end of the tool body and a surface of the flute adjacent the second edge facing away from the forward end of the tool body. Each helical flute can include a first portion having a first negative pitch angle and a second portion having a second negative pitch angle different from the first negative pitch angle, the first portion extending from the forward end of the tool body to the second portion. The tool has only negative pitch angles. A method for machining a stacked material is also disclosed.

End mill cutter having a plurality of cutting edges distributed over the circumference of the mill cutter, having a flank which is adjacent to the respective cutting edge in the circumferential direction and a supporting surface which adjoins the flank on that side which faces away from the cutting edge in the circumferential direction.

A cutting tool having particular usefulness in milling fall includes a plurality of flutes wherein each flute includes a plurality of reliefs spaced equidistant along a leading cutting wall or edge and a second plurality of reliefs spaced equidistant along a trailing cutting wall or edge and wherein the second plurality of reliefs are off set evenly from the first plurality of reliefs. The plurality of reliefs on a second flute are offset from the plurality of reliefs on a first flute by a distance equal to the equidistance of the plurality of reliefs divided by the total number of flutes.

A cutting tool according to one aspect of the present disclosure includes a shaft portion and cutting edge portions. The main cutting edge portions have a main cutting edge. In a section within 30% of a blade length of a region from a center of the region in a direction along the central axis, the main cutting edge portions have first and second nick portions. The main cutting edge portions are formed in the region. The relationship between the first nick portion and the second nick portion satisfies at least one of a first condition and a second condition. The first condition is that a width of the first nick portion is different from a width of the second nick portion. The second condition is that a depth of the first nick portion is different from a depth of the second nick portion.

A body of a cutting tool may include a shank and a tip having spaced-apart, helical flutes. Each spaced-apart, helical flute may include a helical cutting edge extending from a tip bottom, adjacent a shank top, to a tip top. The tip may include chip gash paths. Each chip gash path may be recessed between two of the spaced-apart, helical flutes, and extend from the tip bottom to a tip top portion. The body may include helical coolant channels extending from entrances at a shank bottom, to within a shank interior, to within a tip interior, to tip coolant orifice exits. The coolant orifice exits may be disposed in the spaced-apart, helical flutes adjacent the chip gash paths or disposed in relief surfaces extending from the tip top downward to the chip gash paths. The coolant orifice exits may be spaced-apart from the tip top.