A ridgeline between the thinning face and the flank face includes a first thinning portion contiguous to the outer cutting edge, and a second thinning portion contiguous to the first thinning portion. When viewed in a direction along the central axis, the first thinning portion is linear and the second thinning portion is curved. When viewed in the direction along the central axis, the first thinning portion, and a boundary between the first thinning portion and the second thinning portion are located rearward in a rotational direction relative to a first straight line, and are located forward in the rotational direction relative to a second straight line, the first straight line being a straight line passing through the central axis and parallel to the first thinning portion, and the second straight line being a straight line perpendicular to the first straight line.

A cutting insert may include a base, a cutting edge and a flute. The base may include a rotation axis and may be extended from a first end to a second end. The cutting edge may be located on a side of the first end. The flute may be extended from the cutting edge toward the second end. The cutting edge may include a first cutting edge and a second cutting edge. The first cutting edge may intersect with the rotation axis in a front view. The second cutting edge may be located closer to an outer periphery than the first cutting edge, and a rake angle of the second cutting edge may have a positive value. The first cutting edge may be formed by round honing, and the second cutting edge may be formed by chamfer honing.

The invention relates to a rotary cutting tool (1), such as a drill (2) or a reamer (3), extending longitudinally along an axis (4) and comprising at least one main cutting edge (5) so that when the tool (1) is rotated about the axis (4), the tool (1) advances axially to perform a cutting operation on a material.

According to the invention, the tool (1) comprises means for braking (7) the axial advance of the tool (1) during the cutting operation.

In an embodiment, an insert includes an upper surface including a corner part, a lower surface, a side surface, and a cutting edge. The side surface is between the upper surface and the lower surface. The cutting edge is at least at a part of a first region in which the upper surface intersects with the side surface. The cutting edge includes a first cutting edge at the corner part, a second cutting edge, a third cutting edge, and a fourth cutting edge. The second cutting edge is next to the first cutting edge, and also next to the third cutting edge. The third and fourth cutting edges: each have a convex curvilinear shape with first and second radii of curvature, respectively; and extend downward and upward, respectively, in a side view as going farther from the second cutting edge. The second radius smaller than the first radius.

A device for opening a connection to a lined pipe is disclosed. The device has a body that includes a front end and a rear end and being rotatable about a rotation axis. The device also has a drill head that has multiple cutters for puncturing and enlarging a hole in a liner, and multiple side cutters have at least one cutting edge parallel to the rotation axis. A safety ring is disposed on the body between the drill head and the side cutters. The safety ring has a circular periphery extending beyond the drill head and the side cutters in a direction perpendicular to the rotation axis.

A device for opening a connection to a lined pipe is disclosed. The device has a body that includes a front end and a rear end and being rotatable about a rotation axis. The device also has a drill head that has multiple cutters for puncturing and enlarging a hole in a liner, and multiple side cutters have at least one cutting edge parallel to the rotation axis. A safety ring is disposed on the body between the drill head and the side cutters. The safety ring has a circular periphery extending beyond the drill head and the side cutters in a direction perpendicular to the rotation axis.

A device for opening a connection to a lined pipe is disclosed. The device has a body that includes a front end and a rear end and being rotatable about a rotation axis. The device also has a drill head that has multiple cutters for puncturing and enlarging a hole in a liner, and multiple side cutters have at least one cutting edge parallel to the rotation axis. A safety ring is disposed on the body between the drill head and the side cutters. The safety ring has a circular periphery extending beyond the drill head and the side cutters in a direction perpendicular to the rotation axis.

A method for designing a cutting edge of a cutting element configured for removing material from a workpiece to leave therein a desired end profile (B22,B24,B26). The method comprises the steps of modeling a desired end profile (B22,B24,B26) of the workpiece, the profile having a longitudinal axis and being defined by a bottom surface (B12), a side surface (B16) and an adjustment surface (B14) extending therebetween; defining a lead profile plane (RP.sub.L) and an trail profile plane (RP.sub.T) spaced therefrom, each of the planes being oriented perpendicular to the longitudinal axis; determining a profile contour defined by the intersection line between the end profile (B22,B24,B26) and the lead profile plane (RP.sub.L). The contour profile includes a bottom contour, an adjoining contour and a side contour defined as the intersection lines between the lead profile plane (RP.sub.L) and the bottom surface (B12), the adjustment surface (B14) and the side surface (B16) respectively; designing a rake surface and a relief surface, the intersection line between which defines a cutting edge lying in the adjoining surface (B14) and spanning between the lead profile plane (RP.sub.L) and the trail profile plane (RP.sub.T). The cutting edge is designed such that in any reference plane (RP; FIG. 6A) oriented perpendicularly to the cutting edge, the intersection between each of the rake surface and the relief surface with the reference plane (RP) defines a respective rake line (RK; FIG. 7) and relief line (RF; FIG. 7), the angle (.sub.B) between the lines RK,RF) being equal to or smaller than a similar angle (.sub.B) taken along each of a plurality of similar reference planes (RP) disposed between the reference plane (RP.sub.n) and the lead profile plane (RP.sub.L).

A device for opening a connection to a lined pipe is disclosed. The device has a body that includes a front end and a rear end and being rotatable about a rotation axis. The device also has a drill head that has multiple cutters for puncturing and enlarging a hole in a liner, and multiple side cutters have at least one cutting edge parallel to the rotation axis. A safety ring is disposed on the body between the drill head and the side cutters. The safety ring has a circular periphery extending beyond the drill head and the side cutters in a direction perpendicular to the rotation axis.

In an embodiment, an insert includes an upper surface including a corner part, a lower surface, a side surface, and a cutting edge. The side surface is between the upper surface and the lower surface. The cutting edge is at least at a part of a first region in which the upper surface intersects with the side surface. The cutting edge includes a first cutting edge at the corner part, a second cutting edge, a third cutting edge, and a fourth cutting edge. The second cutting edge is next to the first cutting edge, and also next to the third cutting edge. The third and fourth cutting edges: each have a convex curvilinear shape with first and second radii of curvature, respectively; and extend downward and upward, respectively, in a side view as going farther from the second cutting edge. The second radius smaller than the first radius.