A T-slot cutter (1) is a tool for cutting a T-groove in a workpiece, and includes a body (2A) and an insert portion (3). The insert portion (3) is fixed to a leading end portion of the body (2A) using screws (8). The insert portion (3) is configured by overlaying inserts (4) and (5). By changing a combination of the inserts configuring the insert portion (3), a groove width and an angular shape of the T-groove cut in the workpiece can be easily adjusted. On mating faces of the inserts (4, 5), convex portions and concave portions of the mating face of the insert (4) overlap with concave portions and convex portions of the mating face of the insert (5). As a result, the inserts (4, 5) partially overlap with each other in a thickness direction, and thus a protrusion length of the insert portion (3) can be shortened.

A milling device is rotatable in one direction around a longitudinal center axis defining a forward direction and an opposite rearward direction, and includes a front part and a rear part. The front part has cutting edges, each having a longitudinal extension, and chip flutes, each having a longitudinal extension. The front part is made of a monolithic piece of ceramic. The rear part is configured to be fixed in a rotatable tool body or a rotatable chuck. The rear part is also made of a monolithic piece of cemented carbide. A front end surface of the rear part has a smaller area than a rear end surface of the front part. The front end surface of the rear part and a rear end surface of the front part are permanently bonded or brazed to each other by a joint.

A cutting tool comprises a shank having an insertion portion protruding from a shank main body, a head in which an insertion hole into which the insertion portion is inserted is formed, and a spacer disposed in a gap between the shank main body and the head. The insertion portion has a tapered outer circumferential surface which gradually decreases in diameter from the other side toward one side in the axial direction. The insertion hole has a tapered inner circumferential surface coming into surface contact with the tapered outer circumferential surface. A head end surface of the head which faces the other side in the axial direction comes into surface contact with a surface facing one side in the axial direction of the spacer.

A slotting tool body includes a disc-like cutter portion and a shank portion projecting rearwardly therefrom. The cutter portion includes a resilient clamping portion having a peripherally disposed insert receiving slot. The shank portion includes a peripherally disposed forward shank recess that is axially adjacent the cutter portion. A radially inward portion of the insert receiving slot merges in the rearward direction with the forward shank recess. A cutting insert is releasably and resiliently clamped in the insert receiving slot to form a rotary slot cutting tool. The cutting insert includes two cutting portions that each include a long and short insert lateral extension, the long insert lateral extension being longer than the short insert lateral extension. The longest insert lateral extensions are orated on opposite sides of the cutting insert.

A cutting tool according to one aspect of the present disclosure includes an attaching portion, a cutting portion having a core portion and a surface portion, and a joint portion. The attaching portion includes a hard component and a hard material. The hard component is at least one selected from the group consisting of TiC, TiCN, W, WC, Al.sub.2O.sub.3, and a combination of at least one of CBN and diamond and at least one of W and WC. The hard material includes one or two or more types of iron group elements, and has a Young's modulus of not more than 350 GPa. The core portion includes a cemented carbide material. The surface portion includes PCD or CBN. The cutting portion has a chamfer portion. The surface portion includes a groove, a flank face, and a cutting edge. The cutting edge extends toward the attaching portion.

A main body (3) of a replaceable-tip cutting tool (1) includes a cylinder-shaped cylindrical portion (32) made from a first metal material and extending in an axial direction, and with a female thread portion (33) provided on an inner circumference (40) of the cylindrical portion (32) and capable of being screwed together with a male threaded portion (24) of a cutting head (2). The female thread portion (33) includes a first female thread portion (34) and a second female thread portion (35). The first female thread portion (34) is a portion between a top of a female thread crest (37) of the female thread portion (33) and a portion of the female thread portion (35) that is on the female thread crest (37) side of a female thread root (36) and on the female thread root side of a portion corresponding to an effective diameter of the female thread portion (33). The first female thread portion (34) is made from a second metal material that is different from the first metal material. The second female thread portion (35) is continuous with the inner circumference (40) of the cylindrical portion (32). The second female thread portion is a remaining portion of the female thread portion excluding the first female thread portion. The second female thread portion (35) is made from the first metal material.

A device (1) for exchanging at least one cutting component (2a) of a rotating tool (2), in particular a milling tool (2), and more particularly, a hollow milling tool for machining workpieces made of plastic. The device has an aligning device (5) for orientating a position of the cutting component (2a) relative to a rotational axis (2c) of the tool (2) and an exchanging device (6) for releasing the cutting component (2a) from a part (2b) that remains on the tool (2) and for attaching another cutting component (2a) to the part (2b) that remains on the tool (2).

Provided is a fastening structure having a wide application range and a high degree of freedom of design. A fastening structure includes: a head including a first end surface and a first screw part formed on the first end surface; and a shank including a second end surface and a second screw part formed on the second end surface and threadedly engaging with the first screw part. The first end surface includes a first principal surface oriented in an axial direction of the first screw part and a first step surface oriented in a rotational direction of the first screw part. The second end surface includes a second principal surface oriented in an axial direction of the second screw part and a second step surface oriented in a rotational direction of the second screw part. The first and second principal surfaces face each other and the first and second step surfaces face each other when the first screw part threadedly engages with the second screw part.

A cutting tool assembly includes a tool body and a tool holder including a longitudinal axis around which the tool holder is configured to spin. The tool holder includes a central portion connected to the tool body comprising a fastener hole perpendicular with the longitudinal axis and configured to receive a securing fastener, wherein the fastener hole is offset from the longitudinal axis. The tool holder further includes an eccentric drive member connected to the cylindrical portion. The tool holder can optionally further include an end alignment cylinder connected to the eccentric drive member.

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.