A surgical bur including flutes and lands. Each of the flutes includes a cutting edge, rake surfaces and a clearance surface. The rake surfaces of one of the flutes are decoupled from each other. Each of the lands is disposed between a pair of the flutes.

A single-sided four-way indexable cutting insert includes a positive basic shape, a rake surface, a peripheral surface including four side abutment surfaces, a base bearing surface and a screw hole connecting the rake and base bearing surfaces. The insert has an imaginary square frustum which defines a square base containing the cutting insert's base bearing surface, and further defines four isosceles trapezoid side surfaces respectively containing the cutting insert's four side abutment surfaces. A material volume V.sub.F of the cutting insert and a void volume V.sub.S of the insert fulfill the condition V.sub.S/V.sub.F0.25.

A deburring tool (7) for deburring of edges of transverse recesses (3, 3a-i), which diverge from a main borehole (2), consisting of a shaft (8, 9) driven to turn about the tool axis (11), which is deployable and retractable in the forward feed direction into the main borehole, and on the lower end of which at least one knife window (26) is arranged, in which at least one spring-loaded knife (10, 10, 10, 10, 10) is arranged roughly perpendicular to the tool axis (11), so as to be shiftable, which on its front end has at least one cutting edge (10a, 10b) which encounters the edge of the transverse recess (3, 3a-i), and deburrs same, wherein the knife (10, 10, 10, 10, 10) consists of two cutting edges (10a, 10b) opposite in the rotational direction (12, 13), which act to cut equally for the right and left passes (12, 13), with one cutting edge (10a) being configured to cut for the rightward pass (12), both in forward motion (38a) and in rearward motion, and the other cutting edge (10b), being configured to cut for the leftward pass (13), both in forward motion (38a) and in rearward motion, and that the two cutters (10a, 10b) with their cutting edges are placed at a slant and with arch shape at an angle between 0 and 90, but preferably between 5 and 45 to the tool axis (11) and thus to the longitudinal axis (2a) of the main borehole (2).

A surgical bur including flutes and lands. Each of the flutes includes a cutting edge, rake surfaces and a clearance surface. The rake surfaces of one of the flutes are decoupled from each other. Each of the lands is disposed between a pair of the flutes.

A single-sided four-way indexable cutting insert includes a positive basic shape, a rake surface, a peripheral surface including four side abutment surfaces, a base bearing surface and a screw hole connecting the rake and base bearing surfaces. The insert has an imaginary square frustum which defines a square base containing the cutting insert's base bearing surface, and further defines four isosceles trapezoid side surfaces respectively containing the cutting insert's four side abutment surfaces. A material volume V.sub.F of the cutting insert and a void volume V.sub.S of the insert fulfill the condition V.sub.S/V.sub.F0.25.

A method for forming dimples on a workpiece includes providing a rotary cutting tool. The rotary cutting tool includes a cutting edge that protrudes in a leading direction parallel to a longitudinal axis of the tool. The cutting edge extends from a position at the leading end of the rod-shaped main body that is radially offset from the longitudinal axis. The rotary cutting tool is set such that the longitudinal axis of the rotary cutting tool is inclined relative to a line perpendicular to the processing surface of the workpiece. The rotary cutting tool is moved along the processing surface while the rotary cutting tool is rotated about the axis. The processing surface is cut by the cutting edge to form the dimples, which are spaced apart from each other on the processing surface.

[Object] To provide a ball end mill in which it is possible to improve wear resistance in the vicinity of the central axis at the tip of a ball-nosed end cutting edge and to suppress vibration of a tool body during machining. [Solution] A ball end mill 10 includes: a tool body 1 that rotates about a central axis O; and an arc-shaped ball-nosed end cutting edge 2 in a side view which is provided to start from the central axis O side on a tip side of the tool body 1 toward a rear side thereof. The ball-nosed end cutting edge 2 has a radius of curvature r that becomes gradually smaller from the central axis O side toward a periphery Q side.

A rotary cutting tool includes a shaft having and outer surface and having a longitudinal axis, a plurality of helical flutes formed in the shaft about the longitudinal axis, a plurality of helical cutting edges formed at an interface with the outer surface and a respective helical flute about the longitudinal axis, and a plurality of end cutting edges located on an axial distal end of a cutting portion of the shaft, the end cutting edges being contiguous with a corresponding one of the plurality of helical cutting edges and forming a corner in the transition between each of the end cutting edges and the corresponding one of the plurality of helical cutting edges. A hone edge extends along a portion of each of the end cutting edges, the associated corner and a portion of the corresponding one of the plurality of helical cutting edges.

A disposable drilling and milling cutter for use with an NC or CNC machine tool and configured to be fed in a spiral manner includes a shank, a chip removing groove at one of a plurality of offset positions at one end of the shank, a blade seat at a distal end of the chip removing groove, and a disposable blade locked to the blade seat. The disposable blade has a cutting edge at each of its upper and lower ends, and each cutting edge has an irregular height and a notch. The wavy structural design of the disposable blade enables the disposable drilling and milling cutter to drill and mill in a sectioned manner, to break the drilling/milling chips automatically, and to perform intermittent processing.

Provided is a cutting insert capable of suppressing edge fracture when a work having high hardness is machined. A cutting insert includes two end surfaces having a plurality of corner parts and opposed to each other, a peripheral side surface extending between the two end surfaces, and a cutting edge formed at an intersecting edge between at least one of the two end surfaces and the peripheral side surface. The cutting edge has at least a first corner edge, a second corner edge, a major cutting edge, and an end cutting edge. The end cutting edge has a circular-arc shape, which projects outward, as viewed from the side of the end surface. The end cutting edge has a width which is from 15% to 50% of the width of the cutting insert. The end cutting edge has an arc radius which is from to 1/1 of the width of the cutting insert.