A metal cutting milling tool includes a body having a front end, a plurality of land portions extending axially rearwards from the front end, and a plurality of chip rooms extending axially rearwards from the front end. Each chip room is positioned between two adjacent land portions and each land portion is delimited by a leading and a trailing surface. Each land portion as part of the leading surface in a radially outer and forward region, includes an insert seat for receiving a cutting insert. At the front end of the milling tool, in a plane perpendicular to the central axis, an angle between a radius intersecting a radially outer point in the insert seat of a first land portion and a radius intersecting a corresponding point in the insert seat of a second land portion defines a seat pitch angle for the first land portion.

An end mill machining apparatus, a CAM apparatus, an NC program, and a machining method which suppress regenerative self-excited vibration and mode-coupling self-excited vibration. An end mill machining apparatus includes an end mill, and a control section for controlling the end mill. The ratio of the protrusion length of the end mill to the diameter of the end mill falls within a range of 5 to 50. The end mill is a variable pitch, uniform helix type or a variable helix type. The control section controls the end mill such that the contact angle between the end mill and a workpiece M1 during machining becomes equal to or smaller than a critical contact angle .sub.lim.

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 end mill includes: an end mill body having a rotation axis, the end mill body including a shank portion and a cutting portion with an outer peripheral cutting edge; an end cutting edge including a first cutting edge and a second cutting edge; a first gash opening between the first cutting edge and the second cutting edge; and a second gash located adjacently to the first gash in the rotational direction, and opening to a side closer to the outside peripheral from the chisel portion. A ratio (L1/L2) of a length (L1) from a distal end of the end mill body to a terminal end of the first gash to a length (L2) from the distal end of the end mill body to a terminal end of the second gash, when viewed from a side, is from 0.8 to 1.1.

A rotary cutting tool or end mill is provided, the tool comprising a plurality of pairs of diametrically-opposed, symmetrical, helical flutes formed in a cutting portion of the tool body, wherein the pitch between at least one pair of adjacent helical flutes is less than or greater than the pitch of at least one other pair of adjacent helical flutes in at least one radial plane along the axial length of the flutes, a plurality of peripheral cutting edges, wherein at least one of the peripheral cutting edges has a radial rake angle different from radial rake angle of a peripheral cutting edge of a different helical flute.

An end mill, preferably made of solid carbide, with a fastening section and a cutting area, in which the cutting area is formed by a core and three or four cutting edges running helically around the axis of rotation of the end mill and arranged around core; each of which has a peripheral main cutting edge and a secondary cutting edge on a face of the cutting area. On the face of the cutting area at least one point thinning of core is provided between two adjacent cutting edges. In order to create end mills that are simple to manufacture and optimized for drilling, the point thinning has an angle of 30 to 40 relative to the axis of rotation of the end mill.

A cutting tool includes a main body. The main body includes a distal end surface, a rear end surface, and a side surface. A spiral first groove and a spiral second groove are formed on the side surface of the main body. The first groove has at least four installation surfaces. The first installation surface is located on a most rear end surface side. The second installation surface is located closer to a distal end surface side with respect to the first installation surface. A length from the first installation surface to the second groove in a circumferential direction along the rotation direction of the main body is set to a first length. A length from the second installation surface to the second groove in the circumferential direction is set to a second length. The first length is longer than the second length.

A cutting tool for use in an orbital drilling machine may include a cutting-tool body having a longitudinal axis and a plurality of cutting edges supported on the cutting-tool body and distributed circumferentially around the cutting-tool body. Each cutting edge may extend along the longitudinal axis in a respective helix. A circumferential spacing may be defined between each pair of circumferentially adjacent cutting edges for each position of the longitudinal axis along which the cutting edges extend. The circumferential spacing between at least first and second cutting edges of the plurality of cutting edges may be different at spaced-apart first and second positions along the longitudinal axis.

A rotary cutting tool with a longitudinal axis includes a shank portion and a cutting portion defining a length of cut. The cutting portion includes a plurality of blades separated by flutes extending along the length of cut. A first blade forms a first helix angle with respect to the longitudinal axis at the cutting tip. A second blade adjacent the first blade forms a second, different helix angle with respect to the longitudinal axis at the cutting tip. A third blade adjacent the second blade forms a third, different helix angle with respect to the longitudinal axis at the cutting tip. The first, second and third helix angles deviate by at least 2 degrees. The cutting edges of the first, second and third blades have unequal indexing.

An end mill includes a plurality of teeth and flutes. The teeth and their associated flutes include one or more correlated physical parameters. One such correlated parameter is that, at an axial location in a front half of an effective cutting length, at least one tooth of the plurality of teeth has a rake angle smaller than an average rake angle value of the plurality of teeth, and, at the same axial location, a flute preceding each such tooth has a helix angle larger than an average helix angle value of the plurality of flutes.